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-rw-r--r--057immutable.cc17
-rw-r--r--064list.mu5
-rw-r--r--065duplex_list.mu10
-rw-r--r--html/057immutable.cc.html17
-rw-r--r--html/064list.mu.html709
-rw-r--r--html/065duplex_list.mu.html1440
-rw-r--r--html/edit/001-editor.mu.html18
-rw-r--r--html/edit/002-typing.mu.html40
-rw-r--r--html/edit/003-shortcuts.mu.html128
-rw-r--r--html/edit/004-programming-environment.mu.html14
-rw-r--r--html/edit/005-sandbox.mu.html18
-rw-r--r--html/edit/006-sandbox-copy.mu.html2
-rw-r--r--html/edit/011-errors.mu.html2
-rw-r--r--html/edit/012-editor-undo.mu.html38
-rw-r--r--html/lambda-to-mu.mu.html6
-rw-r--r--html/nqueens.mu.html127
-rw-r--r--nqueens.mu5
17 files changed, 1305 insertions, 1291 deletions
diff --git a/057immutable.cc b/057immutable.cc
index 57d36ceb..e1a17a84 100644
--- a/057immutable.cc
+++ b/057immutable.cc
@@ -562,14 +562,27 @@ if (has_property(current_ingredient, "contained-in")) {
   continue;
 }
 
-:(scenario contained_in_check)
+:(scenario contained_in_product)
 container test-list [
   value:num
   next:&:test-list
 ]
-def test-remove x:&:test-list/contained-in:result, from:&:test-list -> result:&:test-list [
+def foo x:&:test-list/contained-in:result -> result:&:test-list [
   local-scope
   load-ingredients
   result <- copy 0
 ]
 $error: 0
+
+:(scenario contained_in_is_mutable)
+container test-list [
+  value:num
+  next:&:test-list
+]
+def foo x:&:test-list/contained-in:result -> result:&:test-list [
+  local-scope
+  load-ingredients
+  result <- copy x
+  put *x, value:offset, 34
+]
+$error: 0
diff --git a/064list.mu b/064list.mu
index bc8fa9ce..1e10243a 100644
--- a/064list.mu
+++ b/064list.mu
@@ -8,12 +8,11 @@ container list:_elem [
   next:&:list:_elem
 ]
 
-def push x:_elem, l:&:list:_elem -> l:&:list:_elem [
+def push x:_elem, l:&:list:_elem -> result:&:list:_elem/contained-in:l [
   local-scope
   load-ingredients
-  result:&:list:_elem <- new {(list _elem): type}
+  result <- new {(list _elem): type}
   *result <- merge x, l
-  return result
 ]
 
 def first in:&:list:_elem -> result:_elem [
diff --git a/065duplex_list.mu b/065duplex_list.mu
index 97541f33..30552fb6 100644
--- a/065duplex_list.mu
+++ b/065duplex_list.mu
@@ -6,17 +6,13 @@ container duplex-list:_elem [
   prev:&:duplex-list:_elem
 ]
 
-# should I say in/contained-in:result, allow ingredients to refer to products?
-def push x:_elem, in:&:duplex-list:_elem -> in:&:duplex-list:_elem [
+def push x:_elem, in:&:duplex-list:_elem/contained-in:result -> result:&:duplex-list:_elem [
   local-scope
   load-ingredients
   result:&:duplex-list:_elem <- new {(duplex-list _elem): type}
   *result <- merge x, in, 0
-  {
-    break-unless in
-    *in <- put *in, prev:offset, result
-  }
-  return result  # needed explicitly because we need to replace 'in' with 'result'
+  return-unless in
+  put *in, prev:offset, result
 ]
 
 def first in:&:duplex-list:_elem -> result:_elem [
diff --git a/html/057immutable.cc.html b/html/057immutable.cc.html
index bd08a8f2..50e9ad43 100644
--- a/html/057immutable.cc.html
+++ b/html/057immutable.cc.html
@@ -626,17 +626,30 @@ if ('onhashchange' in window) {
 <span id="L562" class="LineNr">562 </span>  <span class="Identifier">continue</span><span class="Delimiter">;</span>
 <span id="L563" class="LineNr">563 </span><span class="Delimiter">}</span>
 <span id="L564" class="LineNr">564 </span>
-<span id="L565" class="LineNr">565 </span><span class="Delimiter">:(scenario contained_in_check)</span>
+<span id="L565" class="LineNr">565 </span><span class="Delimiter">:(scenario contained_in_product)</span>
 <span id="L566" class="LineNr">566 </span><span class="muData">container</span> test-list [
 <span id="L567" class="LineNr">567 </span>  <span class="Normal">value</span>:num
 <span id="L568" class="LineNr">568 </span>  <span class="Normal">next</span>:&amp;:test-list
 <span id="L569" class="LineNr">569 </span>]
-<span id="L570" class="LineNr">570 </span><span class="muRecipe">def</span> test-remove x:&amp;:test-list/contained-in:result<span class="Delimiter">,</span> from:&amp;:test-list<span class="muRecipe"> -&gt; </span>result:&amp;:test-list [
+<span id="L570" class="LineNr">570 </span><span class="muRecipe">def</span> foo x:&amp;:test-list/contained-in:result<span class="muRecipe"> -&gt; </span>result:&amp;:test-list [
 <span id="L571" class="LineNr">571 </span>  local-scope
 <span id="L572" class="LineNr">572 </span>  load-ingredients
 <span id="L573" class="LineNr">573 </span>  result<span class="Special"> &lt;- </span>copy <span class="Constant">0</span>
 <span id="L574" class="LineNr">574 </span>]
 <span id="L575" class="LineNr">575 </span>$error: <span class="Constant">0</span>
+<span id="L576" class="LineNr">576 </span>
+<span id="L577" class="LineNr">577 </span><span class="Delimiter">:(scenario contained_in_is_mutable)</span>
+<span id="L578" class="LineNr">578 </span><span class="muData">container</span> test-list [
+<span id="L579" class="LineNr">579 </span>  <span class="Normal">value</span>:num
+<span id="L580" class="LineNr">580 </span>  <span class="Normal">next</span>:&amp;:test-list
+<span id="L581" class="LineNr">581 </span>]
+<span id="L582" class="LineNr">582 </span><span class="muRecipe">def</span> foo x:&amp;:test-list/contained-in:result<span class="muRecipe"> -&gt; </span>result:&amp;:test-list [
+<span id="L583" class="LineNr">583 </span>  local-scope
+<span id="L584" class="LineNr">584 </span>  load-ingredients
+<span id="L585" class="LineNr">585 </span>  result<span class="Special"> &lt;- </span>copy x
+<span id="L586" class="LineNr">586 </span>  <a href='001help.cc.html#L221'>put</a> *x<span class="Delimiter">,</span> <span class="Constant">value:offset</span><span class="Delimiter">,</span> <span class="Constant">34</span>
+<span id="L587" class="LineNr">587 </span>]
+<span id="L588" class="LineNr">588 </span>$error: <span class="Constant">0</span>
 </pre>
 </body>
 </html>
diff --git a/html/064list.mu.html b/html/064list.mu.html
index 449c16e7..937bf0b9 100644
--- a/html/064list.mu.html
+++ b/html/064list.mu.html
@@ -67,366 +67,365 @@ if ('onhashchange' in window) {
 <span id="L5" class="LineNr">  5 </span>
 <span id="L6" class="LineNr">  6 </span><span class="muData">container</span> <a href='064list.mu.html#L6'>list</a>:_elem [
 <span id="L7" class="LineNr">  7 </span>  value:_elem
-<span id="L8" class="LineNr">  8 </span>  <a href='065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem
+<span id="L8" class="LineNr">  8 </span>  <a href='065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem
 <span id="L9" class="LineNr">  9 </span>]
 <span id="L10" class="LineNr"> 10 </span>
-<span id="L11" class="LineNr"> 11 </span><span class="muRecipe">def</span> push x:_elem, l:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>l:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem [
+<span id="L11" class="LineNr"> 11 </span><span class="muRecipe">def</span> push x:_elem, l:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem/contained-in:l [
 <span id="L12" class="LineNr"> 12 </span>  <span class="Constant">local-scope</span>
 <span id="L13" class="LineNr"> 13 </span>  <span class="Constant">load-ingredients</span>
-<span id="L14" class="LineNr"> 14 </span>  result:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem <span class="Special">&lt;-</span> new <span class="Delimiter">{</span>(list _elem): type<span class="Delimiter">}</span>
+<span id="L14" class="LineNr"> 14 </span>  result <span class="Special">&lt;-</span> new <span class="Delimiter">{</span>(list _elem): type<span class="Delimiter">}</span>
 <span id="L15" class="LineNr"> 15 </span>  *result <span class="Special">&lt;-</span> merge x, l
-<span id="L16" class="LineNr"> 16 </span>  <span class="muControl">return</span> result
-<span id="L17" class="LineNr"> 17 </span>]
-<span id="L18" class="LineNr"> 18 </span>
-<span id="L19" class="LineNr"> 19 </span><span class="muRecipe">def</span> first in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>result:_elem [
-<span id="L20" class="LineNr"> 20 </span>  <span class="Constant">local-scope</span>
-<span id="L21" class="LineNr"> 21 </span>  <span class="Constant">load-ingredients</span>
-<span id="L22" class="LineNr"> 22 </span>  result <span class="Special">&lt;-</span> get *in, <span class="Constant">value:offset</span>
-<span id="L23" class="LineNr"> 23 </span>]
-<span id="L24" class="LineNr"> 24 </span>
-<span id="L25" class="LineNr"> 25 </span><span class="muRecipe">def</span> <a href='064list.mu.html#L25'>rest</a> in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem/contained-in:in [
-<span id="L26" class="LineNr"> 26 </span>  <span class="Constant">local-scope</span>
-<span id="L27" class="LineNr"> 27 </span>  <span class="Constant">load-ingredients</span>
-<span id="L28" class="LineNr"> 28 </span>  result <span class="Special">&lt;-</span> get *in, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>
-<span id="L29" class="LineNr"> 29 </span>]
-<span id="L30" class="LineNr"> 30 </span>
-<span id="L31" class="LineNr"> 31 </span><span class="muScenario">scenario</span> list-handling [
-<span id="L32" class="LineNr"> 32 </span>  run [
-<span id="L33" class="LineNr"> 33 </span>  <span class="Conceal">¦</span> <span class="Constant">local-scope</span>
-<span id="L34" class="LineNr"> 34 </span>  <span class="Conceal">¦</span> x:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L35" class="LineNr"> 35 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, x
-<span id="L36" class="LineNr"> 36 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, x
-<span id="L37" class="LineNr"> 37 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first x
-<span id="L38" class="LineNr"> 38 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> x
-<span id="L39" class="LineNr"> 39 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first x
-<span id="L40" class="LineNr"> 40 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> x
-<span id="L41" class="LineNr"> 41 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first x
-<span id="L42" class="LineNr"> 42 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='064list.mu.html#L6'>list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> x
-<span id="L43" class="LineNr"> 43 </span>  ]
-<span id="L44" class="LineNr"> 44 </span>  memory-should-contain [
-<span id="L45" class="LineNr"> 45 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
-<span id="L46" class="LineNr"> 46 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
-<span id="L47" class="LineNr"> 47 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L48" class="LineNr"> 48 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># nothing left</span>
-<span id="L49" class="LineNr"> 49 </span>  ]
-<span id="L50" class="LineNr"> 50 </span>]
-<span id="L51" class="LineNr"> 51 </span>
-<span id="L52" class="LineNr"> 52 </span><span class="muRecipe">def</span> length l:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>result:num [
-<span id="L53" class="LineNr"> 53 </span>  <span class="Constant">local-scope</span>
-<span id="L54" class="LineNr"> 54 </span>  <span class="Constant">load-ingredients</span>
-<span id="L55" class="LineNr"> 55 </span>  result <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
-<span id="L56" class="LineNr"> 56 </span>  <span class="Delimiter">{</span>
-<span id="L57" class="LineNr"> 57 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> l
-<span id="L58" class="LineNr"> 58 </span>  <span class="Conceal">¦</span> result <span class="Special">&lt;-</span> add result,<span class="Constant"> 1</span>
-<span id="L59" class="LineNr"> 59 </span>  <span class="Conceal">¦</span> l <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> l
-<span id="L60" class="LineNr"> 60 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
-<span id="L61" class="LineNr"> 61 </span>  <span class="Delimiter">}</span>
-<span id="L62" class="LineNr"> 62 </span>]
-<span id="L63" class="LineNr"> 63 </span>
-<span id="L64" class="LineNr"> 64 </span><span class="Comment"># insert 'x' after 'in'</span>
-<span id="L65" class="LineNr"> 65 </span><span class="muRecipe">def</span> insert x:_elem, in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem [
-<span id="L66" class="LineNr"> 66 </span>  <span class="Constant">local-scope</span>
-<span id="L67" class="LineNr"> 67 </span>  <span class="Constant">load-ingredients</span>
-<span id="L68" class="LineNr"> 68 </span>  new-node:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem <span class="Special">&lt;-</span> new <span class="Delimiter">{</span>(list _elem): type<span class="Delimiter">}</span>
-<span id="L69" class="LineNr"> 69 </span>  *new-node <span class="Special">&lt;-</span> put *new-node, <span class="Constant">value:offset</span>, x
-<span id="L70" class="LineNr"> 70 </span>  next-node:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem <span class="Special">&lt;-</span> get *in, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>
-<span id="L71" class="LineNr"> 71 </span>  *in <span class="Special">&lt;-</span> put *in, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>, new-node
-<span id="L72" class="LineNr"> 72 </span>  *new-node <span class="Special">&lt;-</span> put *new-node, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>, next-node
-<span id="L73" class="LineNr"> 73 </span>]
-<span id="L74" class="LineNr"> 74 </span>
-<span id="L75" class="LineNr"> 75 </span><span class="muScenario">scenario</span> inserting-into-list [
-<span id="L76" class="LineNr"> 76 </span>  <span class="Constant">local-scope</span>
-<span id="L77" class="LineNr"> 77 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L78" class="LineNr"> 78 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L79" class="LineNr"> 79 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L80" class="LineNr"> 80 </span>  run [
-<span id="L81" class="LineNr"> 81 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># inside list</span>
-<span id="L82" class="LineNr"> 82 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, list2
-<span id="L83" class="LineNr"> 83 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure</span>
-<span id="L84" class="LineNr"> 84 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L85" class="LineNr"> 85 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L86" class="LineNr"> 86 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L87" class="LineNr"> 87 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L88" class="LineNr"> 88 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L89" class="LineNr"> 89 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L90" class="LineNr"> 90 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L91" class="LineNr"> 91 </span>  <span class="Conceal">¦</span> 13:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L92" class="LineNr"> 92 </span>  ]
-<span id="L93" class="LineNr"> 93 </span>  memory-should-contain [
-<span id="L94" class="LineNr"> 94 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
-<span id="L95" class="LineNr"> 95 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
-<span id="L96" class="LineNr"> 96 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
-<span id="L97" class="LineNr"> 97 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L98" class="LineNr"> 98 </span>  ]
-<span id="L99" class="LineNr"> 99 </span>]
-<span id="L100" class="LineNr">100 </span>
-<span id="L101" class="LineNr">101 </span><span class="muScenario">scenario</span> inserting-at-end-of-list [
-<span id="L102" class="LineNr">102 </span>  <span class="Constant">local-scope</span>
-<span id="L103" class="LineNr">103 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L104" class="LineNr">104 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L105" class="LineNr">105 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L106" class="LineNr">106 </span>  run [
-<span id="L107" class="LineNr">107 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># inside list</span>
-<span id="L108" class="LineNr">108 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2  <span class="Comment"># now at end of list</span>
-<span id="L109" class="LineNr">109 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, list2
-<span id="L110" class="LineNr">110 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
-<span id="L111" class="LineNr">111 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L112" class="LineNr">112 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L113" class="LineNr">113 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L114" class="LineNr">114 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L115" class="LineNr">115 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L116" class="LineNr">116 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L117" class="LineNr">117 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L118" class="LineNr">118 </span>  <span class="Conceal">¦</span> 13:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L119" class="LineNr">119 </span>  ]
-<span id="L120" class="LineNr">120 </span>  memory-should-contain [
-<span id="L121" class="LineNr">121 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
-<span id="L122" class="LineNr">122 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
-<span id="L123" class="LineNr">123 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L124" class="LineNr">124 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
-<span id="L125" class="LineNr">125 </span>  ]
-<span id="L126" class="LineNr">126 </span>]
-<span id="L127" class="LineNr">127 </span>
-<span id="L128" class="LineNr">128 </span><span class="muScenario">scenario</span> inserting-after-start-of-list [
-<span id="L129" class="LineNr">129 </span>  <span class="Constant">local-scope</span>
-<span id="L130" class="LineNr">130 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L131" class="LineNr">131 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L132" class="LineNr">132 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L133" class="LineNr">133 </span>  run [
-<span id="L134" class="LineNr">134 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L135" class="LineNr">135 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
-<span id="L136" class="LineNr">136 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L137" class="LineNr">137 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L138" class="LineNr">138 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L139" class="LineNr">139 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L140" class="LineNr">140 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L141" class="LineNr">141 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L142" class="LineNr">142 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L143" class="LineNr">143 </span>  <span class="Conceal">¦</span> 13:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L144" class="LineNr">144 </span>  ]
-<span id="L145" class="LineNr">145 </span>  memory-should-contain [
-<span id="L146" class="LineNr">146 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
-<span id="L147" class="LineNr">147 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
-<span id="L148" class="LineNr">148 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
-<span id="L149" class="LineNr">149 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L150" class="LineNr">150 </span>  ]
-<span id="L151" class="LineNr">151 </span>]
-<span id="L152" class="LineNr">152 </span>
-<span id="L153" class="LineNr">153 </span><span class="Comment"># remove 'x' from its surrounding list 'in'</span>
-<span id="L154" class="LineNr">154 </span><span class="Comment">#</span>
-<span id="L155" class="LineNr">155 </span><span class="Comment"># Returns null if and only if list is empty. Beware: in that case any other</span>
-<span id="L156" class="LineNr">156 </span><span class="Comment"># pointers to the head are now invalid.</span>
-<span id="L157" class="LineNr">157 </span><span class="muRecipe">def</span> remove x:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem/contained-in:in, in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem [
-<span id="L158" class="LineNr">158 </span>  <span class="Constant">local-scope</span>
-<span id="L159" class="LineNr">159 </span>  <span class="Constant">load-ingredients</span>
-<span id="L160" class="LineNr">160 </span>  <span class="Comment"># if 'x' is null, return</span>
-<span id="L161" class="LineNr">161 </span>  <span class="muControl">return-unless</span> x
-<span id="L162" class="LineNr">162 </span>  next-node:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> x
-<span id="L163" class="LineNr">163 </span>  <span class="Comment"># clear next pointer of 'x'</span>
-<span id="L164" class="LineNr">164 </span>  *x <span class="Special">&lt;-</span> put *x, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>,<span class="Constant"> 0</span>
-<span id="L165" class="LineNr">165 </span>  <span class="Comment"># if 'x' is at the head of 'in', return the new head</span>
-<span id="L166" class="LineNr">166 </span>  at-head?:bool <span class="Special">&lt;-</span> equal x, in
-<span id="L167" class="LineNr">167 </span>  <span class="muControl">return-if</span> at-head?, next-node
-<span id="L168" class="LineNr">168 </span>  <span class="Comment"># compute prev-node</span>
-<span id="L169" class="LineNr">169 </span>  prev-node:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem <span class="Special">&lt;-</span> copy in
-<span id="L170" class="LineNr">170 </span>  curr:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> prev-node
-<span id="L171" class="LineNr">171 </span>  <span class="Delimiter">{</span>
-<span id="L172" class="LineNr">172 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> curr
-<span id="L173" class="LineNr">173 </span>  <span class="Conceal">¦</span> found?:bool <span class="Special">&lt;-</span> equal curr, x
-<span id="L174" class="LineNr">174 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> found?
-<span id="L175" class="LineNr">175 </span>  <span class="Conceal">¦</span> prev-node <span class="Special">&lt;-</span> copy curr
-<span id="L176" class="LineNr">176 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> curr
-<span id="L177" class="LineNr">177 </span>  <span class="Delimiter">}</span>
-<span id="L178" class="LineNr">178 </span>  <span class="Comment"># set its next pointer to skip 'x'</span>
-<span id="L179" class="LineNr">179 </span>  *prev-node <span class="Special">&lt;-</span> put *prev-node, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>, next-node
-<span id="L180" class="LineNr">180 </span>]
-<span id="L181" class="LineNr">181 </span>
-<span id="L182" class="LineNr">182 </span><span class="muScenario">scenario</span> removing-from-list [
-<span id="L183" class="LineNr">183 </span>  <span class="Constant">local-scope</span>
-<span id="L184" class="LineNr">184 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L185" class="LineNr">185 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L186" class="LineNr">186 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L187" class="LineNr">187 </span>  run [
-<span id="L188" class="LineNr">188 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># second element</span>
-<span id="L189" class="LineNr">189 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove list2, <a href='064list.mu.html#L6'>list</a>
-<span id="L190" class="LineNr">190 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal list2,<span class="Constant"> 0</span>
-<span id="L191" class="LineNr">191 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
-<span id="L192" class="LineNr">192 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L193" class="LineNr">193 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L194" class="LineNr">194 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L195" class="LineNr">195 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L196" class="LineNr">196 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='064list.mu.html#L6'>list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L197" class="LineNr">197 </span>  ]
-<span id="L198" class="LineNr">198 </span>  memory-should-contain [
-<span id="L199" class="LineNr">199 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># remove returned non-null</span>
-<span id="L200" class="LineNr">200 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next, skipping deleted element</span>
-<span id="L201" class="LineNr">201 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L202" class="LineNr">202 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
-<span id="L203" class="LineNr">203 </span>  ]
-<span id="L204" class="LineNr">204 </span>]
-<span id="L205" class="LineNr">205 </span>
-<span id="L206" class="LineNr">206 </span><span class="muScenario">scenario</span> removing-from-start-of-list [
-<span id="L207" class="LineNr">207 </span>  <span class="Constant">local-scope</span>
-<span id="L208" class="LineNr">208 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L209" class="LineNr">209 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L210" class="LineNr">210 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L211" class="LineNr">211 </span>  run [
-<span id="L212" class="LineNr">212 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove <a href='064list.mu.html#L6'>list</a>, <a href='064list.mu.html#L6'>list</a>
-<span id="L213" class="LineNr">213 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
-<span id="L214" class="LineNr">214 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L215" class="LineNr">215 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L216" class="LineNr">216 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L217" class="LineNr">217 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L218" class="LineNr">218 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='064list.mu.html#L6'>list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L219" class="LineNr">219 </span>  ]
-<span id="L220" class="LineNr">220 </span>  memory-should-contain [
-<span id="L221" class="LineNr">221 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># scanning next, skipping deleted element</span>
-<span id="L222" class="LineNr">222 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L223" class="LineNr">223 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
-<span id="L224" class="LineNr">224 </span>  ]
-<span id="L225" class="LineNr">225 </span>]
-<span id="L226" class="LineNr">226 </span>
-<span id="L227" class="LineNr">227 </span><span class="muScenario">scenario</span> removing-from-end-of-list [
-<span id="L228" class="LineNr">228 </span>  <span class="Constant">local-scope</span>
-<span id="L229" class="LineNr">229 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L230" class="LineNr">230 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L231" class="LineNr">231 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L232" class="LineNr">232 </span>  run [
-<span id="L233" class="LineNr">233 </span>  <span class="Conceal">¦</span> <span class="Comment"># delete last element</span>
-<span id="L234" class="LineNr">234 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L235" class="LineNr">235 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L236" class="LineNr">236 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove list2, <a href='064list.mu.html#L6'>list</a>
-<span id="L237" class="LineNr">237 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal list2,<span class="Constant"> 0</span>
-<span id="L238" class="LineNr">238 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
-<span id="L239" class="LineNr">239 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L240" class="LineNr">240 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L241" class="LineNr">241 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L242" class="LineNr">242 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L243" class="LineNr">243 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='064list.mu.html#L6'>list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> list2
-<span id="L244" class="LineNr">244 </span>  ]
-<span id="L245" class="LineNr">245 </span>  memory-should-contain [
-<span id="L246" class="LineNr">246 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># remove returned non-null</span>
-<span id="L247" class="LineNr">247 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next, skipping deleted element</span>
-<span id="L248" class="LineNr">248 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
-<span id="L249" class="LineNr">249 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
-<span id="L250" class="LineNr">250 </span>  ]
-<span id="L251" class="LineNr">251 </span>]
-<span id="L252" class="LineNr">252 </span>
-<span id="L253" class="LineNr">253 </span><span class="muScenario">scenario</span> removing-from-singleton-list [
-<span id="L254" class="LineNr">254 </span>  <span class="Constant">local-scope</span>
-<span id="L255" class="LineNr">255 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L256" class="LineNr">256 </span>  run [
-<span id="L257" class="LineNr">257 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove <a href='064list.mu.html#L6'>list</a>, <a href='064list.mu.html#L6'>list</a>
-<span id="L258" class="LineNr">258 </span>  <span class="Conceal">¦</span> 1:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L259" class="LineNr">259 </span>  ]
-<span id="L260" class="LineNr">260 </span>  memory-should-contain [
-<span id="L261" class="LineNr">261 </span>  <span class="Conceal">¦</span><span class="Constant"> 1</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># back to an empty list</span>
-<span id="L262" class="LineNr">262 </span>  ]
-<span id="L263" class="LineNr">263 </span>]
-<span id="L264" class="LineNr">264 </span>
-<span id="L265" class="LineNr">265 </span><span class="Comment"># reverse the elements of a list</span>
-<span id="L266" class="LineNr">266 </span><span class="Comment"># (contributed by Caleb Couch)</span>
-<span id="L267" class="LineNr">267 </span><span class="muRecipe">def</span> reverse <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem temp:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem/contained-in:result<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem [
-<span id="L268" class="LineNr">268 </span>  <span class="Constant">local-scope</span>
-<span id="L269" class="LineNr">269 </span>  <span class="Constant">load-ingredients</span>
-<span id="L270" class="LineNr">270 </span>  <span class="muControl">return-unless</span> <a href='064list.mu.html#L6'>list</a>, temp
-<span id="L271" class="LineNr">271 </span>  object:_elem <span class="Special">&lt;-</span> first, <a href='064list.mu.html#L6'>list</a>
-<span id="L272" class="LineNr">272 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L273" class="LineNr">273 </span>  temp <span class="Special">&lt;-</span> push object, temp
-<span id="L274" class="LineNr">274 </span>  result <span class="Special">&lt;-</span> reverse <a href='064list.mu.html#L6'>list</a>, temp
-<span id="L275" class="LineNr">275 </span>]
-<span id="L276" class="LineNr">276 </span>
-<span id="L277" class="LineNr">277 </span><span class="muScenario">scenario</span> reverse-list [
-<span id="L278" class="LineNr">278 </span>  <span class="Constant">local-scope</span>
-<span id="L279" class="LineNr">279 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 1</span>,<span class="Constant"> 0</span>
-<span id="L280" class="LineNr">280 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 2</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L281" class="LineNr">281 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L282" class="LineNr">282 </span>  run [
-<span id="L283" class="LineNr">283 </span>  <span class="Conceal">¦</span> stash <span class="Constant">[list:]</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L284" class="LineNr">284 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> reverse <a href='064list.mu.html#L6'>list</a>
-<span id="L285" class="LineNr">285 </span>  <span class="Conceal">¦</span> stash <span class="Constant">[reversed:]</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L286" class="LineNr">286 </span>  ]
-<span id="L287" class="LineNr">287 </span>  trace-should-contain [
-<span id="L288" class="LineNr">288 </span>  <span class="Conceal">¦</span> app: <a href='064list.mu.html#L6'>list</a>:<span class="Constant"> 3</span><span class="muRecipe"> -&gt; </span>2<span class="muRecipe"> -&gt; </span>1
-<span id="L289" class="LineNr">289 </span>  <span class="Conceal">¦</span> app: reversed:<span class="Constant"> 1</span><span class="muRecipe"> -&gt; </span>2<span class="muRecipe"> -&gt; </span>3
-<span id="L290" class="LineNr">290 </span>  ]
-<span id="L291" class="LineNr">291 </span>]
-<span id="L292" class="LineNr">292 </span>
-<span id="L293" class="LineNr">293 </span><span class="muScenario">scenario</span> stash-list [
-<span id="L294" class="LineNr">294 </span>  <span class="Constant">local-scope</span>
-<span id="L295" class="LineNr">295 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 1</span>,<span class="Constant"> 0</span>
-<span id="L296" class="LineNr">296 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 2</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L297" class="LineNr">297 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L298" class="LineNr">298 </span>  run [
-<span id="L299" class="LineNr">299 </span>  <span class="Conceal">¦</span> stash <span class="Constant">[list:]</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L300" class="LineNr">300 </span>  ]
-<span id="L301" class="LineNr">301 </span>  trace-should-contain [
-<span id="L302" class="LineNr">302 </span>  <span class="Conceal">¦</span> app: <a href='064list.mu.html#L6'>list</a>:<span class="Constant"> 3</span><span class="muRecipe"> -&gt; </span>2<span class="muRecipe"> -&gt; </span>1
-<span id="L303" class="LineNr">303 </span>  ]
-<span id="L304" class="LineNr">304 </span>]
-<span id="L305" class="LineNr">305 </span>
-<span id="L306" class="LineNr">306 </span><span class="muRecipe">def</span> to-text in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>result:text [
-<span id="L307" class="LineNr">307 </span>  <span class="Constant">local-scope</span>
-<span id="L308" class="LineNr">308 </span>  <span class="Constant">load-ingredients</span>
-<span id="L309" class="LineNr">309 </span>  buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char <span class="Special">&lt;-</span> <a href='061text.mu.html#L125'>new-buffer</a><span class="Constant"> 80</span>
-<span id="L310" class="LineNr">310 </span>  buf <span class="Special">&lt;-</span> to-buffer in, buf
-<span id="L311" class="LineNr">311 </span>  result <span class="Special">&lt;-</span> <a href='061text.mu.html#L338'>buffer-to-array</a> buf
-<span id="L312" class="LineNr">312 </span>]
-<span id="L313" class="LineNr">313 </span>
-<span id="L314" class="LineNr">314 </span><span class="Comment"># variant of 'to-text' which stops printing after a few elements (and so is robust to cycles)</span>
-<span id="L315" class="LineNr">315 </span><span class="muRecipe">def</span> to-text-line in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>result:text [
-<span id="L316" class="LineNr">316 </span>  <span class="Constant">local-scope</span>
-<span id="L317" class="LineNr">317 </span>  <span class="Constant">load-ingredients</span>
-<span id="L318" class="LineNr">318 </span>  buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char <span class="Special">&lt;-</span> <a href='061text.mu.html#L125'>new-buffer</a><span class="Constant"> 80</span>
-<span id="L319" class="LineNr">319 </span>  buf <span class="Special">&lt;-</span> to-buffer in, buf,<span class="Constant"> 6</span>  <span class="Comment"># max elements to display</span>
-<span id="L320" class="LineNr">320 </span>  result <span class="Special">&lt;-</span> <a href='061text.mu.html#L338'>buffer-to-array</a> buf
-<span id="L321" class="LineNr">321 </span>]
-<span id="L322" class="LineNr">322 </span>
-<span id="L323" class="LineNr">323 </span><span class="muRecipe">def</span> to-buffer in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem, buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char<span class="muRecipe"> -&gt; </span>buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char [
-<span id="L324" class="LineNr">324 </span>  <span class="Constant">local-scope</span>
-<span id="L325" class="LineNr">325 </span>  <span class="Constant">load-ingredients</span>
-<span id="L326" class="LineNr">326 </span>  <span class="Delimiter">{</span>
-<span id="L327" class="LineNr">327 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> in
-<span id="L328" class="LineNr">328 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> append buf, <span class="Constant">[[]</span>]
-<span id="L329" class="LineNr">329 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
-<span id="L330" class="LineNr">330 </span>  <span class="Delimiter">}</span>
-<span id="L331" class="LineNr">331 </span>  <span class="Comment"># append in.value to buf</span>
-<span id="L332" class="LineNr">332 </span>  val:_elem <span class="Special">&lt;-</span> get *in, <span class="Constant">value:offset</span>
-<span id="L333" class="LineNr">333 </span>  buf <span class="Special">&lt;-</span> append buf, val
-<span id="L334" class="LineNr">334 </span>  <span class="Comment"># now prepare next</span>
-<span id="L335" class="LineNr">335 </span>  <a href='065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> in
-<span id="L336" class="LineNr">336 </span>  nextn:num <span class="Special">&lt;-</span> copy <a href='065duplex_list.mu.html#L29'>next</a>
-<span id="L337" class="LineNr">337 </span>  <span class="muControl">return-unless</span> <a href='065duplex_list.mu.html#L29'>next</a>
-<span id="L338" class="LineNr">338 </span>  buf <span class="Special">&lt;-</span> append buf, <span class="Constant">[ -&gt; ]</span>
-<span id="L339" class="LineNr">339 </span>  <span class="Comment"># and recurse</span>
-<span id="L340" class="LineNr">340 </span>  remaining:num, optional-ingredient-found?:bool <span class="Special">&lt;-</span> <span class="Constant">next-ingredient</span>
-<span id="L341" class="LineNr">341 </span>  <span class="Delimiter">{</span>
-<span id="L342" class="LineNr">342 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> optional-ingredient-found?
-<span id="L343" class="LineNr">343 </span>  <span class="Conceal">¦</span> <span class="Comment"># unlimited recursion</span>
-<span id="L344" class="LineNr">344 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> to-buffer <a href='065duplex_list.mu.html#L29'>next</a>, buf
-<span id="L345" class="LineNr">345 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
-<span id="L346" class="LineNr">346 </span>  <span class="Delimiter">}</span>
-<span id="L347" class="LineNr">347 </span>  <span class="Delimiter">{</span>
-<span id="L348" class="LineNr">348 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> remaining
-<span id="L349" class="LineNr">349 </span>  <span class="Conceal">¦</span> <span class="Comment"># limited recursion</span>
-<span id="L350" class="LineNr">350 </span>  <span class="Conceal">¦</span> remaining <span class="Special">&lt;-</span> subtract remaining,<span class="Constant"> 1</span>
-<span id="L351" class="LineNr">351 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> to-buffer <a href='065duplex_list.mu.html#L29'>next</a>, buf, remaining
-<span id="L352" class="LineNr">352 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
-<span id="L353" class="LineNr">353 </span>  <span class="Delimiter">}</span>
-<span id="L354" class="LineNr">354 </span>  <span class="Comment"># past recursion depth; insert ellipses and stop</span>
-<span id="L355" class="LineNr">355 </span>  append buf, <span class="Constant">[...]</span>
-<span id="L356" class="LineNr">356 </span>]
-<span id="L357" class="LineNr">357 </span>
-<span id="L358" class="LineNr">358 </span><span class="muScenario">scenario</span> stash-empty-list [
-<span id="L359" class="LineNr">359 </span>  <span class="Constant">local-scope</span>
-<span id="L360" class="LineNr">360 </span>  x:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
-<span id="L361" class="LineNr">361 </span>  run [
-<span id="L362" class="LineNr">362 </span>  <span class="Conceal">¦</span> stash x
-<span id="L363" class="LineNr">363 </span>  ]
-<span id="L364" class="LineNr">364 </span>  trace-should-contain [
-<span id="L365" class="LineNr">365 </span>  <span class="Conceal">¦</span> app: <span class="Constant">[]</span>
-<span id="L366" class="LineNr">366 </span>  ]
-<span id="L367" class="LineNr">367 </span>]
+<span id="L16" class="LineNr"> 16 </span>]
+<span id="L17" class="LineNr"> 17 </span>
+<span id="L18" class="LineNr"> 18 </span><span class="muRecipe">def</span> first in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>result:_elem [
+<span id="L19" class="LineNr"> 19 </span>  <span class="Constant">local-scope</span>
+<span id="L20" class="LineNr"> 20 </span>  <span class="Constant">load-ingredients</span>
+<span id="L21" class="LineNr"> 21 </span>  result <span class="Special">&lt;-</span> get *in, <span class="Constant">value:offset</span>
+<span id="L22" class="LineNr"> 22 </span>]
+<span id="L23" class="LineNr"> 23 </span>
+<span id="L24" class="LineNr"> 24 </span><span class="muRecipe">def</span> <a href='064list.mu.html#L24'>rest</a> in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem/contained-in:in [
+<span id="L25" class="LineNr"> 25 </span>  <span class="Constant">local-scope</span>
+<span id="L26" class="LineNr"> 26 </span>  <span class="Constant">load-ingredients</span>
+<span id="L27" class="LineNr"> 27 </span>  result <span class="Special">&lt;-</span> get *in, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>
+<span id="L28" class="LineNr"> 28 </span>]
+<span id="L29" class="LineNr"> 29 </span>
+<span id="L30" class="LineNr"> 30 </span><span class="muScenario">scenario</span> list-handling [
+<span id="L31" class="LineNr"> 31 </span>  run [
+<span id="L32" class="LineNr"> 32 </span>  <span class="Conceal">¦</span> <span class="Constant">local-scope</span>
+<span id="L33" class="LineNr"> 33 </span>  <span class="Conceal">¦</span> x:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L34" class="LineNr"> 34 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, x
+<span id="L35" class="LineNr"> 35 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, x
+<span id="L36" class="LineNr"> 36 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first x
+<span id="L37" class="LineNr"> 37 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> x
+<span id="L38" class="LineNr"> 38 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first x
+<span id="L39" class="LineNr"> 39 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> x
+<span id="L40" class="LineNr"> 40 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first x
+<span id="L41" class="LineNr"> 41 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='064list.mu.html#L6'>list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> x
+<span id="L42" class="LineNr"> 42 </span>  ]
+<span id="L43" class="LineNr"> 43 </span>  memory-should-contain [
+<span id="L44" class="LineNr"> 44 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
+<span id="L45" class="LineNr"> 45 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
+<span id="L46" class="LineNr"> 46 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L47" class="LineNr"> 47 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># nothing left</span>
+<span id="L48" class="LineNr"> 48 </span>  ]
+<span id="L49" class="LineNr"> 49 </span>]
+<span id="L50" class="LineNr"> 50 </span>
+<span id="L51" class="LineNr"> 51 </span><span class="muRecipe">def</span> length l:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>result:num [
+<span id="L52" class="LineNr"> 52 </span>  <span class="Constant">local-scope</span>
+<span id="L53" class="LineNr"> 53 </span>  <span class="Constant">load-ingredients</span>
+<span id="L54" class="LineNr"> 54 </span>  result <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
+<span id="L55" class="LineNr"> 55 </span>  <span class="Delimiter">{</span>
+<span id="L56" class="LineNr"> 56 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> l
+<span id="L57" class="LineNr"> 57 </span>  <span class="Conceal">¦</span> result <span class="Special">&lt;-</span> add result,<span class="Constant"> 1</span>
+<span id="L58" class="LineNr"> 58 </span>  <span class="Conceal">¦</span> l <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> l
+<span id="L59" class="LineNr"> 59 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L60" class="LineNr"> 60 </span>  <span class="Delimiter">}</span>
+<span id="L61" class="LineNr"> 61 </span>]
+<span id="L62" class="LineNr"> 62 </span>
+<span id="L63" class="LineNr"> 63 </span><span class="Comment"># insert 'x' after 'in'</span>
+<span id="L64" class="LineNr"> 64 </span><span class="muRecipe">def</span> insert x:_elem, in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem [
+<span id="L65" class="LineNr"> 65 </span>  <span class="Constant">local-scope</span>
+<span id="L66" class="LineNr"> 66 </span>  <span class="Constant">load-ingredients</span>
+<span id="L67" class="LineNr"> 67 </span>  new-node:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem <span class="Special">&lt;-</span> new <span class="Delimiter">{</span>(list _elem): type<span class="Delimiter">}</span>
+<span id="L68" class="LineNr"> 68 </span>  *new-node <span class="Special">&lt;-</span> put *new-node, <span class="Constant">value:offset</span>, x
+<span id="L69" class="LineNr"> 69 </span>  next-node:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem <span class="Special">&lt;-</span> get *in, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>
+<span id="L70" class="LineNr"> 70 </span>  *in <span class="Special">&lt;-</span> put *in, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>, new-node
+<span id="L71" class="LineNr"> 71 </span>  *new-node <span class="Special">&lt;-</span> put *new-node, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>, next-node
+<span id="L72" class="LineNr"> 72 </span>]
+<span id="L73" class="LineNr"> 73 </span>
+<span id="L74" class="LineNr"> 74 </span><span class="muScenario">scenario</span> inserting-into-list [
+<span id="L75" class="LineNr"> 75 </span>  <span class="Constant">local-scope</span>
+<span id="L76" class="LineNr"> 76 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L77" class="LineNr"> 77 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L78" class="LineNr"> 78 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L79" class="LineNr"> 79 </span>  run [
+<span id="L80" class="LineNr"> 80 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># inside list</span>
+<span id="L81" class="LineNr"> 81 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, list2
+<span id="L82" class="LineNr"> 82 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure</span>
+<span id="L83" class="LineNr"> 83 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L84" class="LineNr"> 84 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L85" class="LineNr"> 85 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L86" class="LineNr"> 86 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L87" class="LineNr"> 87 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L88" class="LineNr"> 88 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L89" class="LineNr"> 89 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L90" class="LineNr"> 90 </span>  <span class="Conceal">¦</span> 13:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L91" class="LineNr"> 91 </span>  ]
+<span id="L92" class="LineNr"> 92 </span>  memory-should-contain [
+<span id="L93" class="LineNr"> 93 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
+<span id="L94" class="LineNr"> 94 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
+<span id="L95" class="LineNr"> 95 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
+<span id="L96" class="LineNr"> 96 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L97" class="LineNr"> 97 </span>  ]
+<span id="L98" class="LineNr"> 98 </span>]
+<span id="L99" class="LineNr"> 99 </span>
+<span id="L100" class="LineNr">100 </span><span class="muScenario">scenario</span> inserting-at-end-of-list [
+<span id="L101" class="LineNr">101 </span>  <span class="Constant">local-scope</span>
+<span id="L102" class="LineNr">102 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L103" class="LineNr">103 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L104" class="LineNr">104 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L105" class="LineNr">105 </span>  run [
+<span id="L106" class="LineNr">106 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># inside list</span>
+<span id="L107" class="LineNr">107 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2  <span class="Comment"># now at end of list</span>
+<span id="L108" class="LineNr">108 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, list2
+<span id="L109" class="LineNr">109 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
+<span id="L110" class="LineNr">110 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L111" class="LineNr">111 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L112" class="LineNr">112 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L113" class="LineNr">113 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L114" class="LineNr">114 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L115" class="LineNr">115 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L116" class="LineNr">116 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L117" class="LineNr">117 </span>  <span class="Conceal">¦</span> 13:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L118" class="LineNr">118 </span>  ]
+<span id="L119" class="LineNr">119 </span>  memory-should-contain [
+<span id="L120" class="LineNr">120 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
+<span id="L121" class="LineNr">121 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
+<span id="L122" class="LineNr">122 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L123" class="LineNr">123 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
+<span id="L124" class="LineNr">124 </span>  ]
+<span id="L125" class="LineNr">125 </span>]
+<span id="L126" class="LineNr">126 </span>
+<span id="L127" class="LineNr">127 </span><span class="muScenario">scenario</span> inserting-after-start-of-list [
+<span id="L128" class="LineNr">128 </span>  <span class="Constant">local-scope</span>
+<span id="L129" class="LineNr">129 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L130" class="LineNr">130 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L131" class="LineNr">131 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L132" class="LineNr">132 </span>  run [
+<span id="L133" class="LineNr">133 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L134" class="LineNr">134 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
+<span id="L135" class="LineNr">135 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L136" class="LineNr">136 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L137" class="LineNr">137 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L138" class="LineNr">138 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L139" class="LineNr">139 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L140" class="LineNr">140 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L141" class="LineNr">141 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L142" class="LineNr">142 </span>  <span class="Conceal">¦</span> 13:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L143" class="LineNr">143 </span>  ]
+<span id="L144" class="LineNr">144 </span>  memory-should-contain [
+<span id="L145" class="LineNr">145 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
+<span id="L146" class="LineNr">146 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
+<span id="L147" class="LineNr">147 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
+<span id="L148" class="LineNr">148 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L149" class="LineNr">149 </span>  ]
+<span id="L150" class="LineNr">150 </span>]
+<span id="L151" class="LineNr">151 </span>
+<span id="L152" class="LineNr">152 </span><span class="Comment"># remove 'x' from its surrounding list 'in'</span>
+<span id="L153" class="LineNr">153 </span><span class="Comment">#</span>
+<span id="L154" class="LineNr">154 </span><span class="Comment"># Returns null if and only if list is empty. Beware: in that case any other</span>
+<span id="L155" class="LineNr">155 </span><span class="Comment"># pointers to the head are now invalid.</span>
+<span id="L156" class="LineNr">156 </span><span class="muRecipe">def</span> remove x:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem/contained-in:in, in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem [
+<span id="L157" class="LineNr">157 </span>  <span class="Constant">local-scope</span>
+<span id="L158" class="LineNr">158 </span>  <span class="Constant">load-ingredients</span>
+<span id="L159" class="LineNr">159 </span>  <span class="Comment"># if 'x' is null, return</span>
+<span id="L160" class="LineNr">160 </span>  <span class="muControl">return-unless</span> x
+<span id="L161" class="LineNr">161 </span>  next-node:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> x
+<span id="L162" class="LineNr">162 </span>  <span class="Comment"># clear next pointer of 'x'</span>
+<span id="L163" class="LineNr">163 </span>  *x <span class="Special">&lt;-</span> put *x, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>,<span class="Constant"> 0</span>
+<span id="L164" class="LineNr">164 </span>  <span class="Comment"># if 'x' is at the head of 'in', return the new head</span>
+<span id="L165" class="LineNr">165 </span>  at-head?:bool <span class="Special">&lt;-</span> equal x, in
+<span id="L166" class="LineNr">166 </span>  <span class="muControl">return-if</span> at-head?, next-node
+<span id="L167" class="LineNr">167 </span>  <span class="Comment"># compute prev-node</span>
+<span id="L168" class="LineNr">168 </span>  prev-node:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem <span class="Special">&lt;-</span> copy in
+<span id="L169" class="LineNr">169 </span>  curr:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> prev-node
+<span id="L170" class="LineNr">170 </span>  <span class="Delimiter">{</span>
+<span id="L171" class="LineNr">171 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> curr
+<span id="L172" class="LineNr">172 </span>  <span class="Conceal">¦</span> found?:bool <span class="Special">&lt;-</span> equal curr, x
+<span id="L173" class="LineNr">173 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> found?
+<span id="L174" class="LineNr">174 </span>  <span class="Conceal">¦</span> prev-node <span class="Special">&lt;-</span> copy curr
+<span id="L175" class="LineNr">175 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> curr
+<span id="L176" class="LineNr">176 </span>  <span class="Delimiter">}</span>
+<span id="L177" class="LineNr">177 </span>  <span class="Comment"># set its next pointer to skip 'x'</span>
+<span id="L178" class="LineNr">178 </span>  *prev-node <span class="Special">&lt;-</span> put *prev-node, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>, next-node
+<span id="L179" class="LineNr">179 </span>]
+<span id="L180" class="LineNr">180 </span>
+<span id="L181" class="LineNr">181 </span><span class="muScenario">scenario</span> removing-from-list [
+<span id="L182" class="LineNr">182 </span>  <span class="Constant">local-scope</span>
+<span id="L183" class="LineNr">183 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L184" class="LineNr">184 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L185" class="LineNr">185 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L186" class="LineNr">186 </span>  run [
+<span id="L187" class="LineNr">187 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># second element</span>
+<span id="L188" class="LineNr">188 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove list2, <a href='064list.mu.html#L6'>list</a>
+<span id="L189" class="LineNr">189 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal list2,<span class="Constant"> 0</span>
+<span id="L190" class="LineNr">190 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
+<span id="L191" class="LineNr">191 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L192" class="LineNr">192 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L193" class="LineNr">193 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L194" class="LineNr">194 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L195" class="LineNr">195 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='064list.mu.html#L6'>list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L196" class="LineNr">196 </span>  ]
+<span id="L197" class="LineNr">197 </span>  memory-should-contain [
+<span id="L198" class="LineNr">198 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># remove returned non-null</span>
+<span id="L199" class="LineNr">199 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next, skipping deleted element</span>
+<span id="L200" class="LineNr">200 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L201" class="LineNr">201 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
+<span id="L202" class="LineNr">202 </span>  ]
+<span id="L203" class="LineNr">203 </span>]
+<span id="L204" class="LineNr">204 </span>
+<span id="L205" class="LineNr">205 </span><span class="muScenario">scenario</span> removing-from-start-of-list [
+<span id="L206" class="LineNr">206 </span>  <span class="Constant">local-scope</span>
+<span id="L207" class="LineNr">207 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L208" class="LineNr">208 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L209" class="LineNr">209 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L210" class="LineNr">210 </span>  run [
+<span id="L211" class="LineNr">211 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove <a href='064list.mu.html#L6'>list</a>, <a href='064list.mu.html#L6'>list</a>
+<span id="L212" class="LineNr">212 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
+<span id="L213" class="LineNr">213 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L214" class="LineNr">214 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L215" class="LineNr">215 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L216" class="LineNr">216 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L217" class="LineNr">217 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='064list.mu.html#L6'>list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L218" class="LineNr">218 </span>  ]
+<span id="L219" class="LineNr">219 </span>  memory-should-contain [
+<span id="L220" class="LineNr">220 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># scanning next, skipping deleted element</span>
+<span id="L221" class="LineNr">221 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L222" class="LineNr">222 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
+<span id="L223" class="LineNr">223 </span>  ]
+<span id="L224" class="LineNr">224 </span>]
+<span id="L225" class="LineNr">225 </span>
+<span id="L226" class="LineNr">226 </span><span class="muScenario">scenario</span> removing-from-end-of-list [
+<span id="L227" class="LineNr">227 </span>  <span class="Constant">local-scope</span>
+<span id="L228" class="LineNr">228 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L229" class="LineNr">229 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L230" class="LineNr">230 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L231" class="LineNr">231 </span>  run [
+<span id="L232" class="LineNr">232 </span>  <span class="Conceal">¦</span> <span class="Comment"># delete last element</span>
+<span id="L233" class="LineNr">233 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L234" class="LineNr">234 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L235" class="LineNr">235 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove list2, <a href='064list.mu.html#L6'>list</a>
+<span id="L236" class="LineNr">236 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal list2,<span class="Constant"> 0</span>
+<span id="L237" class="LineNr">237 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
+<span id="L238" class="LineNr">238 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L239" class="LineNr">239 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L240" class="LineNr">240 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L241" class="LineNr">241 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L242" class="LineNr">242 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='064list.mu.html#L6'>list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> list2
+<span id="L243" class="LineNr">243 </span>  ]
+<span id="L244" class="LineNr">244 </span>  memory-should-contain [
+<span id="L245" class="LineNr">245 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># remove returned non-null</span>
+<span id="L246" class="LineNr">246 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next, skipping deleted element</span>
+<span id="L247" class="LineNr">247 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
+<span id="L248" class="LineNr">248 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
+<span id="L249" class="LineNr">249 </span>  ]
+<span id="L250" class="LineNr">250 </span>]
+<span id="L251" class="LineNr">251 </span>
+<span id="L252" class="LineNr">252 </span><span class="muScenario">scenario</span> removing-from-singleton-list [
+<span id="L253" class="LineNr">253 </span>  <span class="Constant">local-scope</span>
+<span id="L254" class="LineNr">254 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L255" class="LineNr">255 </span>  run [
+<span id="L256" class="LineNr">256 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove <a href='064list.mu.html#L6'>list</a>, <a href='064list.mu.html#L6'>list</a>
+<span id="L257" class="LineNr">257 </span>  <span class="Conceal">¦</span> 1:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L258" class="LineNr">258 </span>  ]
+<span id="L259" class="LineNr">259 </span>  memory-should-contain [
+<span id="L260" class="LineNr">260 </span>  <span class="Conceal">¦</span><span class="Constant"> 1</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># back to an empty list</span>
+<span id="L261" class="LineNr">261 </span>  ]
+<span id="L262" class="LineNr">262 </span>]
+<span id="L263" class="LineNr">263 </span>
+<span id="L264" class="LineNr">264 </span><span class="Comment"># reverse the elements of a list</span>
+<span id="L265" class="LineNr">265 </span><span class="Comment"># (contributed by Caleb Couch)</span>
+<span id="L266" class="LineNr">266 </span><span class="muRecipe">def</span> reverse <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem temp:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem/contained-in:result<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem [
+<span id="L267" class="LineNr">267 </span>  <span class="Constant">local-scope</span>
+<span id="L268" class="LineNr">268 </span>  <span class="Constant">load-ingredients</span>
+<span id="L269" class="LineNr">269 </span>  <span class="muControl">return-unless</span> <a href='064list.mu.html#L6'>list</a>, temp
+<span id="L270" class="LineNr">270 </span>  object:_elem <span class="Special">&lt;-</span> first, <a href='064list.mu.html#L6'>list</a>
+<span id="L271" class="LineNr">271 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L272" class="LineNr">272 </span>  temp <span class="Special">&lt;-</span> push object, temp
+<span id="L273" class="LineNr">273 </span>  result <span class="Special">&lt;-</span> reverse <a href='064list.mu.html#L6'>list</a>, temp
+<span id="L274" class="LineNr">274 </span>]
+<span id="L275" class="LineNr">275 </span>
+<span id="L276" class="LineNr">276 </span><span class="muScenario">scenario</span> reverse-list [
+<span id="L277" class="LineNr">277 </span>  <span class="Constant">local-scope</span>
+<span id="L278" class="LineNr">278 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 1</span>,<span class="Constant"> 0</span>
+<span id="L279" class="LineNr">279 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 2</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L280" class="LineNr">280 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L281" class="LineNr">281 </span>  run [
+<span id="L282" class="LineNr">282 </span>  <span class="Conceal">¦</span> stash <span class="Constant">[list:]</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L283" class="LineNr">283 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> reverse <a href='064list.mu.html#L6'>list</a>
+<span id="L284" class="LineNr">284 </span>  <span class="Conceal">¦</span> stash <span class="Constant">[reversed:]</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L285" class="LineNr">285 </span>  ]
+<span id="L286" class="LineNr">286 </span>  trace-should-contain [
+<span id="L287" class="LineNr">287 </span>  <span class="Conceal">¦</span> app: <a href='064list.mu.html#L6'>list</a>:<span class="Constant"> 3</span><span class="muRecipe"> -&gt; </span>2<span class="muRecipe"> -&gt; </span>1
+<span id="L288" class="LineNr">288 </span>  <span class="Conceal">¦</span> app: reversed:<span class="Constant"> 1</span><span class="muRecipe"> -&gt; </span>2<span class="muRecipe"> -&gt; </span>3
+<span id="L289" class="LineNr">289 </span>  ]
+<span id="L290" class="LineNr">290 </span>]
+<span id="L291" class="LineNr">291 </span>
+<span id="L292" class="LineNr">292 </span><span class="muScenario">scenario</span> stash-list [
+<span id="L293" class="LineNr">293 </span>  <span class="Constant">local-scope</span>
+<span id="L294" class="LineNr">294 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 1</span>,<span class="Constant"> 0</span>
+<span id="L295" class="LineNr">295 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 2</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L296" class="LineNr">296 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L297" class="LineNr">297 </span>  run [
+<span id="L298" class="LineNr">298 </span>  <span class="Conceal">¦</span> stash <span class="Constant">[list:]</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L299" class="LineNr">299 </span>  ]
+<span id="L300" class="LineNr">300 </span>  trace-should-contain [
+<span id="L301" class="LineNr">301 </span>  <span class="Conceal">¦</span> app: <a href='064list.mu.html#L6'>list</a>:<span class="Constant"> 3</span><span class="muRecipe"> -&gt; </span>2<span class="muRecipe"> -&gt; </span>1
+<span id="L302" class="LineNr">302 </span>  ]
+<span id="L303" class="LineNr">303 </span>]
+<span id="L304" class="LineNr">304 </span>
+<span id="L305" class="LineNr">305 </span><span class="muRecipe">def</span> to-text in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>result:text [
+<span id="L306" class="LineNr">306 </span>  <span class="Constant">local-scope</span>
+<span id="L307" class="LineNr">307 </span>  <span class="Constant">load-ingredients</span>
+<span id="L308" class="LineNr">308 </span>  buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char <span class="Special">&lt;-</span> <a href='061text.mu.html#L125'>new-buffer</a><span class="Constant"> 80</span>
+<span id="L309" class="LineNr">309 </span>  buf <span class="Special">&lt;-</span> to-buffer in, buf
+<span id="L310" class="LineNr">310 </span>  result <span class="Special">&lt;-</span> <a href='061text.mu.html#L338'>buffer-to-array</a> buf
+<span id="L311" class="LineNr">311 </span>]
+<span id="L312" class="LineNr">312 </span>
+<span id="L313" class="LineNr">313 </span><span class="Comment"># variant of 'to-text' which stops printing after a few elements (and so is robust to cycles)</span>
+<span id="L314" class="LineNr">314 </span><span class="muRecipe">def</span> to-text-line in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem<span class="muRecipe"> -&gt; </span>result:text [
+<span id="L315" class="LineNr">315 </span>  <span class="Constant">local-scope</span>
+<span id="L316" class="LineNr">316 </span>  <span class="Constant">load-ingredients</span>
+<span id="L317" class="LineNr">317 </span>  buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char <span class="Special">&lt;-</span> <a href='061text.mu.html#L125'>new-buffer</a><span class="Constant"> 80</span>
+<span id="L318" class="LineNr">318 </span>  buf <span class="Special">&lt;-</span> to-buffer in, buf,<span class="Constant"> 6</span>  <span class="Comment"># max elements to display</span>
+<span id="L319" class="LineNr">319 </span>  result <span class="Special">&lt;-</span> <a href='061text.mu.html#L338'>buffer-to-array</a> buf
+<span id="L320" class="LineNr">320 </span>]
+<span id="L321" class="LineNr">321 </span>
+<span id="L322" class="LineNr">322 </span><span class="muRecipe">def</span> to-buffer in:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem, buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char<span class="muRecipe"> -&gt; </span>buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char [
+<span id="L323" class="LineNr">323 </span>  <span class="Constant">local-scope</span>
+<span id="L324" class="LineNr">324 </span>  <span class="Constant">load-ingredients</span>
+<span id="L325" class="LineNr">325 </span>  <span class="Delimiter">{</span>
+<span id="L326" class="LineNr">326 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> in
+<span id="L327" class="LineNr">327 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> append buf, <span class="Constant">[[]</span>]
+<span id="L328" class="LineNr">328 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
+<span id="L329" class="LineNr">329 </span>  <span class="Delimiter">}</span>
+<span id="L330" class="LineNr">330 </span>  <span class="Comment"># append in.value to buf</span>
+<span id="L331" class="LineNr">331 </span>  val:_elem <span class="Special">&lt;-</span> get *in, <span class="Constant">value:offset</span>
+<span id="L332" class="LineNr">332 </span>  buf <span class="Special">&lt;-</span> append buf, val
+<span id="L333" class="LineNr">333 </span>  <span class="Comment"># now prepare next</span>
+<span id="L334" class="LineNr">334 </span>  <a href='065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='064list.mu.html#L6'>list</a>:_elem <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> in
+<span id="L335" class="LineNr">335 </span>  nextn:num <span class="Special">&lt;-</span> copy <a href='065duplex_list.mu.html#L25'>next</a>
+<span id="L336" class="LineNr">336 </span>  <span class="muControl">return-unless</span> <a href='065duplex_list.mu.html#L25'>next</a>
+<span id="L337" class="LineNr">337 </span>  buf <span class="Special">&lt;-</span> append buf, <span class="Constant">[ -&gt; ]</span>
+<span id="L338" class="LineNr">338 </span>  <span class="Comment"># and recurse</span>
+<span id="L339" class="LineNr">339 </span>  remaining:num, optional-ingredient-found?:bool <span class="Special">&lt;-</span> <span class="Constant">next-ingredient</span>
+<span id="L340" class="LineNr">340 </span>  <span class="Delimiter">{</span>
+<span id="L341" class="LineNr">341 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> optional-ingredient-found?
+<span id="L342" class="LineNr">342 </span>  <span class="Conceal">¦</span> <span class="Comment"># unlimited recursion</span>
+<span id="L343" class="LineNr">343 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> to-buffer <a href='065duplex_list.mu.html#L25'>next</a>, buf
+<span id="L344" class="LineNr">344 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
+<span id="L345" class="LineNr">345 </span>  <span class="Delimiter">}</span>
+<span id="L346" class="LineNr">346 </span>  <span class="Delimiter">{</span>
+<span id="L347" class="LineNr">347 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> remaining
+<span id="L348" class="LineNr">348 </span>  <span class="Conceal">¦</span> <span class="Comment"># limited recursion</span>
+<span id="L349" class="LineNr">349 </span>  <span class="Conceal">¦</span> remaining <span class="Special">&lt;-</span> subtract remaining,<span class="Constant"> 1</span>
+<span id="L350" class="LineNr">350 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> to-buffer <a href='065duplex_list.mu.html#L25'>next</a>, buf, remaining
+<span id="L351" class="LineNr">351 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
+<span id="L352" class="LineNr">352 </span>  <span class="Delimiter">}</span>
+<span id="L353" class="LineNr">353 </span>  <span class="Comment"># past recursion depth; insert ellipses and stop</span>
+<span id="L354" class="LineNr">354 </span>  append buf, <span class="Constant">[...]</span>
+<span id="L355" class="LineNr">355 </span>]
+<span id="L356" class="LineNr">356 </span>
+<span id="L357" class="LineNr">357 </span><span class="muScenario">scenario</span> stash-empty-list [
+<span id="L358" class="LineNr">358 </span>  <span class="Constant">local-scope</span>
+<span id="L359" class="LineNr">359 </span>  x:&amp;:<a href='064list.mu.html#L6'>list</a>:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
+<span id="L360" class="LineNr">360 </span>  run [
+<span id="L361" class="LineNr">361 </span>  <span class="Conceal">¦</span> stash x
+<span id="L362" class="LineNr">362 </span>  ]
+<span id="L363" class="LineNr">363 </span>  trace-should-contain [
+<span id="L364" class="LineNr">364 </span>  <span class="Conceal">¦</span> app: <span class="Constant">[]</span>
+<span id="L365" class="LineNr">365 </span>  ]
+<span id="L366" class="LineNr">366 </span>]
 </pre>
 </body>
 </html>
diff --git a/html/065duplex_list.mu.html b/html/065duplex_list.mu.html
index d9642574..d01d6819 100644
--- a/html/065duplex_list.mu.html
+++ b/html/065duplex_list.mu.html
@@ -64,730 +64,726 @@ if ('onhashchange' in window) {
 <span id="L2" class="LineNr">  2 </span>
 <span id="L3" class="LineNr">  3 </span><span class="muData">container</span> <a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
 <span id="L4" class="LineNr">  4 </span>  value:_elem
-<span id="L5" class="LineNr">  5 </span>  <a href='065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem
-<span id="L6" class="LineNr">  6 </span>  <a href='065duplex_list.mu.html#L36'>prev</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem
+<span id="L5" class="LineNr">  5 </span>  <a href='065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem
+<span id="L6" class="LineNr">  6 </span>  <a href='065duplex_list.mu.html#L32'>prev</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem
 <span id="L7" class="LineNr">  7 </span>]
 <span id="L8" class="LineNr">  8 </span>
-<span id="L9" class="LineNr">  9 </span><span class="Comment"># should I say in/contained-in:result, allow ingredients to refer to products?</span>
-<span id="L10" class="LineNr"> 10 </span><span class="muRecipe">def</span> push x:_elem, in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
-<span id="L11" class="LineNr"> 11 </span>  <span class="Constant">local-scope</span>
-<span id="L12" class="LineNr"> 12 </span>  <span class="Constant">load-ingredients</span>
-<span id="L13" class="LineNr"> 13 </span>  result:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> new <span class="Delimiter">{</span>(duplex-list _elem): type<span class="Delimiter">}</span>
-<span id="L14" class="LineNr"> 14 </span>  *result <span class="Special">&lt;-</span> merge x, in,<span class="Constant"> 0</span>
-<span id="L15" class="LineNr"> 15 </span>  <span class="Delimiter">{</span>
-<span id="L16" class="LineNr"> 16 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> in
-<span id="L17" class="LineNr"> 17 </span>  <span class="Conceal">¦</span> *in <span class="Special">&lt;-</span> put *in, <span class="Constant"><a href='065duplex_list.mu.html#L36'>prev</a>:offset</span>, result
-<span id="L18" class="LineNr"> 18 </span>  <span class="Delimiter">}</span>
-<span id="L19" class="LineNr"> 19 </span>  <span class="muControl">return</span> result  <span class="Comment"># needed explicitly because we need to replace 'in' with 'result'</span>
-<span id="L20" class="LineNr"> 20 </span>]
-<span id="L21" class="LineNr"> 21 </span>
-<span id="L22" class="LineNr"> 22 </span><span class="muRecipe">def</span> first in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>result:_elem [
-<span id="L23" class="LineNr"> 23 </span>  <span class="Constant">local-scope</span>
-<span id="L24" class="LineNr"> 24 </span>  <span class="Constant">load-ingredients</span>
-<span id="L25" class="LineNr"> 25 </span>  <span class="muControl">return-unless</span> in,<span class="Constant"> 0</span>
-<span id="L26" class="LineNr"> 26 </span>  result <span class="Special">&lt;-</span> get *in, <span class="Constant">value:offset</span>
-<span id="L27" class="LineNr"> 27 </span>]
-<span id="L28" class="LineNr"> 28 </span>
-<span id="L29" class="LineNr"> 29 </span><span class="muRecipe">def</span> <a href='065duplex_list.mu.html#L29'>next</a> in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:in [
-<span id="L30" class="LineNr"> 30 </span>  <span class="Constant">local-scope</span>
-<span id="L31" class="LineNr"> 31 </span>  <span class="Constant">load-ingredients</span>
-<span id="L32" class="LineNr"> 32 </span>  <span class="muControl">return-unless</span> in,<span class="Constant"> 0</span>
-<span id="L33" class="LineNr"> 33 </span>  result <span class="Special">&lt;-</span> get *in, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>
-<span id="L34" class="LineNr"> 34 </span>]
-<span id="L35" class="LineNr"> 35 </span>
-<span id="L36" class="LineNr"> 36 </span><span class="muRecipe">def</span> <a href='065duplex_list.mu.html#L36'>prev</a> in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:in [
-<span id="L37" class="LineNr"> 37 </span>  <span class="Constant">local-scope</span>
-<span id="L38" class="LineNr"> 38 </span>  <span class="Constant">load-ingredients</span>
-<span id="L39" class="LineNr"> 39 </span>  <span class="muControl">return-unless</span> in,<span class="Constant"> 0</span>
-<span id="L40" class="LineNr"> 40 </span>  result <span class="Special">&lt;-</span> get *in, <span class="Constant"><a href='065duplex_list.mu.html#L36'>prev</a>:offset</span>
-<span id="L41" class="LineNr"> 41 </span>  <span class="muControl">return</span> result
-<span id="L42" class="LineNr"> 42 </span>]
-<span id="L43" class="LineNr"> 43 </span>
-<span id="L44" class="LineNr"> 44 </span><span class="muScenario">scenario</span> duplex-list-handling [
-<span id="L45" class="LineNr"> 45 </span>  run [
-<span id="L46" class="LineNr"> 46 </span>  <span class="Conceal">¦</span> <span class="Constant">local-scope</span>
-<span id="L47" class="LineNr"> 47 </span>  <span class="Conceal">¦</span> <span class="Comment"># reserve locations 0-9 to check for missing null check</span>
-<span id="L48" class="LineNr"> 48 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> copy<span class="Constant"> 34</span>
-<span id="L49" class="LineNr"> 49 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> copy<span class="Constant"> 35</span>
-<span id="L50" class="LineNr"> 50 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L51" class="LineNr"> 51 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L52" class="LineNr"> 52 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L53" class="LineNr"> 53 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L54" class="LineNr"> 54 </span>  <span class="Conceal">¦</span> 20:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L55" class="LineNr"> 55 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L56" class="LineNr"> 56 </span>  <span class="Conceal">¦</span> 21:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L57" class="LineNr"> 57 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L58" class="LineNr"> 58 </span>  <span class="Conceal">¦</span> 22:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L59" class="LineNr"> 59 </span>  <span class="Conceal">¦</span> 30:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L60" class="LineNr"> 60 </span>  <span class="Conceal">¦</span> 31:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first 30:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span>
-<span id="L61" class="LineNr"> 61 </span>  <span class="Conceal">¦</span> 32:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> 30:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span>
-<span id="L62" class="LineNr"> 62 </span>  <span class="Conceal">¦</span> 33:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> 30:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span>
-<span id="L63" class="LineNr"> 63 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L64" class="LineNr"> 64 </span>  <span class="Conceal">¦</span> 40:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L65" class="LineNr"> 65 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L66" class="LineNr"> 66 </span>  <span class="Conceal">¦</span> 41:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L67" class="LineNr"> 67 </span>  <span class="Conceal">¦</span> 50:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
-<span id="L68" class="LineNr"> 68 </span>  ]
-<span id="L69" class="LineNr"> 69 </span>  memory-should-contain [
-<span id="L70" class="LineNr"> 70 </span>  <span class="Conceal">¦</span><span class="Constant"> 0</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no modifications to null pointers</span>
-<span id="L71" class="LineNr"> 71 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 34</span>
-<span id="L72" class="LineNr"> 72 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 35</span>
-<span id="L73" class="LineNr"> 73 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
-<span id="L74" class="LineNr"> 74 </span>  <span class="Conceal">¦</span><span class="Constant"> 21</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
-<span id="L75" class="LineNr"> 75 </span>  <span class="Conceal">¦</span><span class="Constant"> 22</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L76" class="LineNr"> 76 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># null</span>
-<span id="L77" class="LineNr"> 77 </span>  <span class="Conceal">¦</span><span class="Constant"> 31</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># first of null</span>
-<span id="L78" class="LineNr"> 78 </span>  <span class="Conceal">¦</span><span class="Constant"> 32</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># next of null</span>
-<span id="L79" class="LineNr"> 79 </span>  <span class="Conceal">¦</span><span class="Constant"> 33</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># prev of null</span>
-<span id="L80" class="LineNr"> 80 </span>  <span class="Conceal">¦</span><span class="Constant"> 40</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># then start scanning prev</span>
-<span id="L81" class="LineNr"> 81 </span>  <span class="Conceal">¦</span><span class="Constant"> 41</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
-<span id="L82" class="LineNr"> 82 </span>  <span class="Conceal">¦</span><span class="Constant"> 50</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
-<span id="L83" class="LineNr"> 83 </span>  ]
-<span id="L84" class="LineNr"> 84 </span>]
-<span id="L85" class="LineNr"> 85 </span>
-<span id="L86" class="LineNr"> 86 </span><span class="muRecipe">def</span> length l:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>result:num [
-<span id="L87" class="LineNr"> 87 </span>  <span class="Constant">local-scope</span>
-<span id="L88" class="LineNr"> 88 </span>  <span class="Constant">load-ingredients</span>
-<span id="L89" class="LineNr"> 89 </span>  result <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
-<span id="L90" class="LineNr"> 90 </span>  <span class="Delimiter">{</span>
-<span id="L91" class="LineNr"> 91 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> l
-<span id="L92" class="LineNr"> 92 </span>  <span class="Conceal">¦</span> result <span class="Special">&lt;-</span> add result,<span class="Constant"> 1</span>
-<span id="L93" class="LineNr"> 93 </span>  <span class="Conceal">¦</span> l <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> l
-<span id="L94" class="LineNr"> 94 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
-<span id="L95" class="LineNr"> 95 </span>  <span class="Delimiter">}</span>
-<span id="L96" class="LineNr"> 96 </span>]
-<span id="L97" class="LineNr"> 97 </span>
-<span id="L98" class="LineNr"> 98 </span><span class="Comment"># insert 'x' after 'in'</span>
-<span id="L99" class="LineNr"> 99 </span><span class="muRecipe">def</span> insert x:_elem, in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
-<span id="L100" class="LineNr">100 </span>  <span class="Constant">local-scope</span>
-<span id="L101" class="LineNr">101 </span>  <span class="Constant">load-ingredients</span>
-<span id="L102" class="LineNr">102 </span>  new-node:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> new <span class="Delimiter">{</span>(duplex-list _elem): type<span class="Delimiter">}</span>
-<span id="L103" class="LineNr">103 </span>  *new-node <span class="Special">&lt;-</span> put *new-node, <span class="Constant">value:offset</span>, x
-<span id="L104" class="LineNr">104 </span>  <span class="Comment"># save old next before changing it</span>
-<span id="L105" class="LineNr">105 </span>  next-node:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> get *in, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>
-<span id="L106" class="LineNr">106 </span>  *in <span class="Special">&lt;-</span> put *in, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>, new-node
-<span id="L107" class="LineNr">107 </span>  *new-node <span class="Special">&lt;-</span> put *new-node, <span class="Constant"><a href='065duplex_list.mu.html#L36'>prev</a>:offset</span>, in
-<span id="L108" class="LineNr">108 </span>  *new-node <span class="Special">&lt;-</span> put *new-node, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>, next-node
-<span id="L109" class="LineNr">109 </span>  <span class="muControl">return-unless</span> next-node
-<span id="L110" class="LineNr">110 </span>  *next-node <span class="Special">&lt;-</span> put *next-node, <span class="Constant"><a href='065duplex_list.mu.html#L36'>prev</a>:offset</span>, new-node
-<span id="L111" class="LineNr">111 </span>]
-<span id="L112" class="LineNr">112 </span>
-<span id="L113" class="LineNr">113 </span><span class="muScenario">scenario</span> inserting-into-duplex-list [
-<span id="L114" class="LineNr">114 </span>  <span class="Constant">local-scope</span>
-<span id="L115" class="LineNr">115 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L116" class="LineNr">116 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L117" class="LineNr">117 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L118" class="LineNr">118 </span>  run [
-<span id="L119" class="LineNr">119 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># inside list</span>
-<span id="L120" class="LineNr">120 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, list2
-<span id="L121" class="LineNr">121 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
-<span id="L122" class="LineNr">122 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L123" class="LineNr">123 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L124" class="LineNr">124 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L125" class="LineNr">125 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L126" class="LineNr">126 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L127" class="LineNr">127 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L128" class="LineNr">128 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L129" class="LineNr">129 </span>  <span class="Conceal">¦</span> 13:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L130" class="LineNr">130 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L131" class="LineNr">131 </span>  <span class="Conceal">¦</span> 20:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L132" class="LineNr">132 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L133" class="LineNr">133 </span>  <span class="Conceal">¦</span> 21:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L134" class="LineNr">134 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L135" class="LineNr">135 </span>  <span class="Conceal">¦</span> 22:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L136" class="LineNr">136 </span>  <span class="Conceal">¦</span> 30:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
-<span id="L137" class="LineNr">137 </span>  ]
-<span id="L138" class="LineNr">138 </span>  memory-should-contain [
-<span id="L139" class="LineNr">139 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
-<span id="L140" class="LineNr">140 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
-<span id="L141" class="LineNr">141 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
-<span id="L142" class="LineNr">142 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L143" class="LineNr">143 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># then prev</span>
-<span id="L144" class="LineNr">144 </span>  <span class="Conceal">¦</span><span class="Constant"> 21</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
-<span id="L145" class="LineNr">145 </span>  <span class="Conceal">¦</span><span class="Constant"> 22</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
-<span id="L146" class="LineNr">146 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
-<span id="L147" class="LineNr">147 </span>  ]
-<span id="L148" class="LineNr">148 </span>]
-<span id="L149" class="LineNr">149 </span>
-<span id="L150" class="LineNr">150 </span><span class="muScenario">scenario</span> inserting-at-end-of-duplex-list [
-<span id="L151" class="LineNr">151 </span>  <span class="Constant">local-scope</span>
-<span id="L152" class="LineNr">152 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L153" class="LineNr">153 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L154" class="LineNr">154 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L155" class="LineNr">155 </span>  run [
-<span id="L156" class="LineNr">156 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># inside list</span>
-<span id="L157" class="LineNr">157 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2  <span class="Comment"># now at end of list</span>
-<span id="L158" class="LineNr">158 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, list2
-<span id="L159" class="LineNr">159 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
-<span id="L160" class="LineNr">160 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L161" class="LineNr">161 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L162" class="LineNr">162 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L163" class="LineNr">163 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L164" class="LineNr">164 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L165" class="LineNr">165 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L166" class="LineNr">166 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L167" class="LineNr">167 </span>  <span class="Conceal">¦</span> 13:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L168" class="LineNr">168 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L169" class="LineNr">169 </span>  <span class="Conceal">¦</span> 20:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L170" class="LineNr">170 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L171" class="LineNr">171 </span>  <span class="Conceal">¦</span> 21:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L172" class="LineNr">172 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L173" class="LineNr">173 </span>  <span class="Conceal">¦</span> 22:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L174" class="LineNr">174 </span>  <span class="Conceal">¦</span> 30:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
-<span id="L175" class="LineNr">175 </span>  ]
-<span id="L176" class="LineNr">176 </span>  memory-should-contain [
-<span id="L177" class="LineNr">177 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
-<span id="L178" class="LineNr">178 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
-<span id="L179" class="LineNr">179 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L180" class="LineNr">180 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
-<span id="L181" class="LineNr">181 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># then prev</span>
-<span id="L182" class="LineNr">182 </span>  <span class="Conceal">¦</span><span class="Constant"> 21</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
-<span id="L183" class="LineNr">183 </span>  <span class="Conceal">¦</span><span class="Constant"> 22</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
-<span id="L184" class="LineNr">184 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
-<span id="L185" class="LineNr">185 </span>  ]
-<span id="L186" class="LineNr">186 </span>]
-<span id="L187" class="LineNr">187 </span>
-<span id="L188" class="LineNr">188 </span><span class="muScenario">scenario</span> inserting-after-start-of-duplex-list [
-<span id="L189" class="LineNr">189 </span>  <span class="Constant">local-scope</span>
-<span id="L190" class="LineNr">190 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L191" class="LineNr">191 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L192" class="LineNr">192 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L193" class="LineNr">193 </span>  run [
-<span id="L194" class="LineNr">194 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L195" class="LineNr">195 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
-<span id="L196" class="LineNr">196 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L197" class="LineNr">197 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L198" class="LineNr">198 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L199" class="LineNr">199 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L200" class="LineNr">200 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L201" class="LineNr">201 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L202" class="LineNr">202 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L203" class="LineNr">203 </span>  <span class="Conceal">¦</span> 13:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L204" class="LineNr">204 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L205" class="LineNr">205 </span>  <span class="Conceal">¦</span> 20:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L206" class="LineNr">206 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L207" class="LineNr">207 </span>  <span class="Conceal">¦</span> 21:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L208" class="LineNr">208 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L209" class="LineNr">209 </span>  <span class="Conceal">¦</span> 22:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L210" class="LineNr">210 </span>  <span class="Conceal">¦</span> 30:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
-<span id="L211" class="LineNr">211 </span>  ]
-<span id="L212" class="LineNr">212 </span>  memory-should-contain [
-<span id="L213" class="LineNr">213 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
-<span id="L214" class="LineNr">214 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
-<span id="L215" class="LineNr">215 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
-<span id="L216" class="LineNr">216 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L217" class="LineNr">217 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># then prev</span>
-<span id="L218" class="LineNr">218 </span>  <span class="Conceal">¦</span><span class="Constant"> 21</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>
-<span id="L219" class="LineNr">219 </span>  <span class="Conceal">¦</span><span class="Constant"> 22</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
-<span id="L220" class="LineNr">220 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
-<span id="L221" class="LineNr">221 </span>  ]
-<span id="L222" class="LineNr">222 </span>]
-<span id="L223" class="LineNr">223 </span>
-<span id="L224" class="LineNr">224 </span><span class="Comment"># remove 'x' from its surrounding list 'in'</span>
-<span id="L225" class="LineNr">225 </span><span class="Comment">#</span>
-<span id="L226" class="LineNr">226 </span><span class="Comment"># Returns null if and only if list is empty. Beware: in that case any other</span>
-<span id="L227" class="LineNr">227 </span><span class="Comment"># pointers to the head are now invalid.</span>
-<span id="L228" class="LineNr">228 </span><span class="muRecipe">def</span> remove x:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:in, in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
-<span id="L229" class="LineNr">229 </span>  <span class="Constant">local-scope</span>
-<span id="L230" class="LineNr">230 </span>  <span class="Constant">load-ingredients</span>
-<span id="L231" class="LineNr">231 </span>  <span class="Comment"># if 'x' is null, return</span>
-<span id="L232" class="LineNr">232 </span>  <span class="muControl">return-unless</span> x
-<span id="L233" class="LineNr">233 </span>  next-node:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> get *x, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>
-<span id="L234" class="LineNr">234 </span>  prev-node:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> get *x, <span class="Constant"><a href='065duplex_list.mu.html#L36'>prev</a>:offset</span>
-<span id="L235" class="LineNr">235 </span>  <span class="Comment"># null x's pointers</span>
-<span id="L236" class="LineNr">236 </span>  *x <span class="Special">&lt;-</span> put *x, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>,<span class="Constant"> 0</span>
-<span id="L237" class="LineNr">237 </span>  *x <span class="Special">&lt;-</span> put *x, <span class="Constant"><a href='065duplex_list.mu.html#L36'>prev</a>:offset</span>,<span class="Constant"> 0</span>
-<span id="L238" class="LineNr">238 </span>  <span class="Comment"># if next-node is not null, set its prev pointer</span>
-<span id="L239" class="LineNr">239 </span>  <span class="Delimiter">{</span>
-<span id="L240" class="LineNr">240 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> next-node
-<span id="L241" class="LineNr">241 </span>  <span class="Conceal">¦</span> *next-node <span class="Special">&lt;-</span> put *next-node, <span class="Constant"><a href='065duplex_list.mu.html#L36'>prev</a>:offset</span>, prev-node
-<span id="L242" class="LineNr">242 </span>  <span class="Delimiter">}</span>
-<span id="L243" class="LineNr">243 </span>  <span class="Comment"># if prev-node is not null, set its next pointer and return</span>
-<span id="L244" class="LineNr">244 </span>  <span class="Delimiter">{</span>
-<span id="L245" class="LineNr">245 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> prev-node
-<span id="L246" class="LineNr">246 </span>  <span class="Conceal">¦</span> *prev-node <span class="Special">&lt;-</span> put *prev-node, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>, next-node
-<span id="L247" class="LineNr">247 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
-<span id="L248" class="LineNr">248 </span>  <span class="Delimiter">}</span>
-<span id="L249" class="LineNr">249 </span>  <span class="Comment"># if prev-node is null, then we removed the head node at 'in'</span>
-<span id="L250" class="LineNr">250 </span>  <span class="Comment"># return the new head rather than the old 'in'</span>
-<span id="L251" class="LineNr">251 </span>  <span class="muControl">return</span> next-node
-<span id="L252" class="LineNr">252 </span>]
-<span id="L253" class="LineNr">253 </span>
-<span id="L254" class="LineNr">254 </span><span class="muScenario">scenario</span> removing-from-duplex-list [
-<span id="L255" class="LineNr">255 </span>  <span class="Constant">local-scope</span>
-<span id="L256" class="LineNr">256 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L257" class="LineNr">257 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L258" class="LineNr">258 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L259" class="LineNr">259 </span>  run [
-<span id="L260" class="LineNr">260 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># second element</span>
-<span id="L261" class="LineNr">261 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove list2, <a href='064list.mu.html#L6'>list</a>
-<span id="L262" class="LineNr">262 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal list2,<span class="Constant"> 0</span>
-<span id="L263" class="LineNr">263 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
-<span id="L264" class="LineNr">264 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L265" class="LineNr">265 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L266" class="LineNr">266 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L267" class="LineNr">267 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L268" class="LineNr">268 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L269" class="LineNr">269 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L270" class="LineNr">270 </span>  <span class="Conceal">¦</span> 30:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L271" class="LineNr">271 </span>  <span class="Conceal">¦</span> 40:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
-<span id="L272" class="LineNr">272 </span>  ]
-<span id="L273" class="LineNr">273 </span>  memory-should-contain [
-<span id="L274" class="LineNr">274 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># remove returned non-null</span>
-<span id="L275" class="LineNr">275 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next, skipping deleted element</span>
-<span id="L276" class="LineNr">276 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L277" class="LineNr">277 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
-<span id="L278" class="LineNr">278 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># prev of final element</span>
-<span id="L279" class="LineNr">279 </span>  <span class="Conceal">¦</span><span class="Constant"> 40</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
-<span id="L280" class="LineNr">280 </span>  ]
-<span id="L281" class="LineNr">281 </span>]
-<span id="L282" class="LineNr">282 </span>
-<span id="L283" class="LineNr">283 </span><span class="muScenario">scenario</span> removing-from-start-of-duplex-list [
-<span id="L284" class="LineNr">284 </span>  <span class="Constant">local-scope</span>
-<span id="L285" class="LineNr">285 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L286" class="LineNr">286 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L287" class="LineNr">287 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L288" class="LineNr">288 </span>  run [
-<span id="L289" class="LineNr">289 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove <a href='064list.mu.html#L6'>list</a>, <a href='064list.mu.html#L6'>list</a>
-<span id="L290" class="LineNr">290 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
-<span id="L291" class="LineNr">291 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L292" class="LineNr">292 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L293" class="LineNr">293 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L294" class="LineNr">294 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L295" class="LineNr">295 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L296" class="LineNr">296 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L297" class="LineNr">297 </span>  <span class="Conceal">¦</span> 30:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L298" class="LineNr">298 </span>  <span class="Conceal">¦</span> 40:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
-<span id="L299" class="LineNr">299 </span>  ]
-<span id="L300" class="LineNr">300 </span>  memory-should-contain [
-<span id="L301" class="LineNr">301 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># scanning next, skipping deleted element</span>
-<span id="L302" class="LineNr">302 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
-<span id="L303" class="LineNr">303 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
-<span id="L304" class="LineNr">304 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># prev of final element</span>
-<span id="L305" class="LineNr">305 </span>  <span class="Conceal">¦</span><span class="Constant"> 40</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
-<span id="L306" class="LineNr">306 </span>  ]
-<span id="L307" class="LineNr">307 </span>]
-<span id="L308" class="LineNr">308 </span>
-<span id="L309" class="LineNr">309 </span><span class="muScenario">scenario</span> removing-from-end-of-duplex-list [
-<span id="L310" class="LineNr">310 </span>  <span class="Constant">local-scope</span>
-<span id="L311" class="LineNr">311 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L312" class="LineNr">312 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L313" class="LineNr">313 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L314" class="LineNr">314 </span>  run [
-<span id="L315" class="LineNr">315 </span>  <span class="Conceal">¦</span> <span class="Comment"># delete last element</span>
-<span id="L316" class="LineNr">316 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L317" class="LineNr">317 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L318" class="LineNr">318 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove list2, <a href='064list.mu.html#L6'>list</a>
-<span id="L319" class="LineNr">319 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal list2,<span class="Constant"> 0</span>
-<span id="L320" class="LineNr">320 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
-<span id="L321" class="LineNr">321 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L322" class="LineNr">322 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L323" class="LineNr">323 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L324" class="LineNr">324 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L325" class="LineNr">325 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L326" class="LineNr">326 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L36'>prev</a> list2
-<span id="L327" class="LineNr">327 </span>  <span class="Conceal">¦</span> 30:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
-<span id="L328" class="LineNr">328 </span>  <span class="Conceal">¦</span> 40:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
-<span id="L329" class="LineNr">329 </span>  ]
-<span id="L330" class="LineNr">330 </span>  memory-should-contain [
-<span id="L331" class="LineNr">331 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># remove returned non-null</span>
-<span id="L332" class="LineNr">332 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next, skipping deleted element</span>
-<span id="L333" class="LineNr">333 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
-<span id="L334" class="LineNr">334 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
-<span id="L335" class="LineNr">335 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># prev of final element</span>
-<span id="L336" class="LineNr">336 </span>  <span class="Conceal">¦</span><span class="Constant"> 40</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
-<span id="L337" class="LineNr">337 </span>  ]
-<span id="L338" class="LineNr">338 </span>]
-<span id="L339" class="LineNr">339 </span>
-<span id="L340" class="LineNr">340 </span><span class="muScenario">scenario</span> removing-from-singleton-duplex-list [
-<span id="L341" class="LineNr">341 </span>  <span class="Constant">local-scope</span>
-<span id="L342" class="LineNr">342 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L343" class="LineNr">343 </span>  run [
-<span id="L344" class="LineNr">344 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove <a href='064list.mu.html#L6'>list</a>, <a href='064list.mu.html#L6'>list</a>
-<span id="L345" class="LineNr">345 </span>  <span class="Conceal">¦</span> 1:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
-<span id="L346" class="LineNr">346 </span>  ]
-<span id="L347" class="LineNr">347 </span>  memory-should-contain [
-<span id="L348" class="LineNr">348 </span>  <span class="Conceal">¦</span><span class="Constant"> 1</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># back to an empty list</span>
-<span id="L349" class="LineNr">349 </span>  ]
-<span id="L350" class="LineNr">350 </span>]
-<span id="L351" class="LineNr">351 </span>
-<span id="L352" class="LineNr">352 </span><span class="muRecipe">def</span> remove x:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:in, n:num, in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
-<span id="L353" class="LineNr">353 </span>  <span class="Constant">local-scope</span>
-<span id="L354" class="LineNr">354 </span>  <span class="Constant">load-ingredients</span>
-<span id="L355" class="LineNr">355 </span>  i:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
-<span id="L356" class="LineNr">356 </span>  curr:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> copy x
-<span id="L357" class="LineNr">357 </span>  <span class="Delimiter">{</span>
-<span id="L358" class="LineNr">358 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal i, n
-<span id="L359" class="LineNr">359 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
-<span id="L360" class="LineNr">360 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
-<span id="L361" class="LineNr">361 </span>  <span class="Conceal">¦</span> <a href='065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> curr
-<span id="L362" class="LineNr">362 </span>  <span class="Conceal">¦</span> in <span class="Special">&lt;-</span> remove curr, in
-<span id="L363" class="LineNr">363 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> copy <a href='065duplex_list.mu.html#L29'>next</a>
-<span id="L364" class="LineNr">364 </span>  <span class="Conceal">¦</span> i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
-<span id="L365" class="LineNr">365 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
-<span id="L366" class="LineNr">366 </span>  <span class="Delimiter">}</span>
-<span id="L367" class="LineNr">367 </span>]
-<span id="L368" class="LineNr">368 </span>
-<span id="L369" class="LineNr">369 </span><span class="muScenario">scenario</span> removing-multiple-from-duplex-list [
-<span id="L370" class="LineNr">370 </span>  <span class="Constant">local-scope</span>
-<span id="L371" class="LineNr">371 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
-<span id="L372" class="LineNr">372 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L373" class="LineNr">373 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L374" class="LineNr">374 </span>  run [
-<span id="L375" class="LineNr">375 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># second element</span>
-<span id="L376" class="LineNr">376 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove list2,<span class="Constant"> 2</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L377" class="LineNr">377 </span>  <span class="Conceal">¦</span> stash <a href='064list.mu.html#L6'>list</a>
-<span id="L378" class="LineNr">378 </span>  ]
-<span id="L379" class="LineNr">379 </span>  trace-should-contain [
-<span id="L380" class="LineNr">380 </span>  <span class="Conceal">¦</span> app:<span class="Constant"> 5</span>
-<span id="L381" class="LineNr">381 </span>  ]
-<span id="L382" class="LineNr">382 </span>]
-<span id="L383" class="LineNr">383 </span>
-<span id="L384" class="LineNr">384 </span><span class="Comment"># remove values between 'start' and 'end' (both exclusive).</span>
-<span id="L385" class="LineNr">385 </span><span class="Comment"># also clear pointers back out from start/end for hygiene.</span>
-<span id="L386" class="LineNr">386 </span><span class="Comment"># set end to 0 to delete everything past start.</span>
-<span id="L387" class="LineNr">387 </span><span class="Comment"># can't set start to 0 to delete everything before end, because there's no</span>
-<span id="L388" class="LineNr">388 </span><span class="Comment"># clean way to return the new head pointer.</span>
-<span id="L389" class="LineNr">389 </span><span class="muRecipe">def</span> <a href='065duplex_list.mu.html#L389'>remove-between</a> start:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem, end:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:start<span class="muRecipe"> -&gt; </span>start:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
-<span id="L390" class="LineNr">390 </span>  <span class="Constant">local-scope</span>
-<span id="L391" class="LineNr">391 </span>  <span class="Constant">load-ingredients</span>
-<span id="L392" class="LineNr">392 </span>  <a href='065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> get *start, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>
-<span id="L393" class="LineNr">393 </span>  nothing-to-delete?:bool <span class="Special">&lt;-</span> equal <a href='065duplex_list.mu.html#L29'>next</a>, end
-<span id="L394" class="LineNr">394 </span>  <span class="muControl">return-if</span> nothing-to-delete?
-<span id="L395" class="LineNr">395 </span>  assert <a href='065duplex_list.mu.html#L29'>next</a>, <span class="Constant">[malformed duplex list]</span>
-<span id="L396" class="LineNr">396 </span>  <span class="Comment"># start-&gt;next-&gt;prev = 0</span>
-<span id="L397" class="LineNr">397 </span>  <span class="Comment"># start-&gt;next = end</span>
-<span id="L398" class="LineNr">398 </span>  *next <span class="Special">&lt;-</span> put *next, <span class="Constant"><a href='065duplex_list.mu.html#L36'>prev</a>:offset</span>,<span class="Constant"> 0</span>
-<span id="L399" class="LineNr">399 </span>  *start <span class="Special">&lt;-</span> put *start, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>, end
-<span id="L400" class="LineNr">400 </span>  <span class="muControl">return-unless</span> end
-<span id="L401" class="LineNr">401 </span>  <span class="Comment"># end-&gt;prev-&gt;next = 0</span>
-<span id="L402" class="LineNr">402 </span>  <span class="Comment"># end-&gt;prev = start</span>
-<span id="L403" class="LineNr">403 </span>  <a href='065duplex_list.mu.html#L36'>prev</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> get *end, <span class="Constant"><a href='065duplex_list.mu.html#L36'>prev</a>:offset</span>
-<span id="L404" class="LineNr">404 </span>  assert <a href='065duplex_list.mu.html#L36'>prev</a>, <span class="Constant">[malformed duplex <a href='064list.mu.html#L6'>list</a> - 2]</span>
-<span id="L405" class="LineNr">405 </span>  *prev <span class="Special">&lt;-</span> put *prev, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>,<span class="Constant"> 0</span>
-<span id="L406" class="LineNr">406 </span>  *end <span class="Special">&lt;-</span> put *end, <span class="Constant"><a href='065duplex_list.mu.html#L36'>prev</a>:offset</span>, start
-<span id="L407" class="LineNr">407 </span>]
-<span id="L408" class="LineNr">408 </span>
-<span id="L409" class="LineNr">409 </span><span class="muScenario">scenario</span> remove-range [
-<span id="L410" class="LineNr">410 </span>  <span class="Comment"># construct a duplex list with six elements [13, 14, 15, 16, 17, 18]</span>
-<span id="L411" class="LineNr">411 </span>  <span class="Constant">local-scope</span>
-<span id="L412" class="LineNr">412 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 18</span>,<span class="Constant"> 0</span>
-<span id="L413" class="LineNr">413 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 17</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L414" class="LineNr">414 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 16</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L415" class="LineNr">415 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 15</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L416" class="LineNr">416 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 14</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L417" class="LineNr">417 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 13</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L418" class="LineNr">418 </span>  run [
-<span id="L419" class="LineNr">419 </span>  <span class="Conceal">¦</span> <span class="Comment"># delete 16 onwards</span>
-<span id="L420" class="LineNr">420 </span>  <span class="Conceal">¦</span> <span class="Comment"># first pointer: to the third element</span>
-<span id="L421" class="LineNr">421 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L422" class="LineNr">422 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L423" class="LineNr">423 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L389'>remove-between</a> list2,<span class="Constant"> 0</span>
-<span id="L424" class="LineNr">424 </span>  <span class="Conceal">¦</span> <span class="Comment"># now check the list</span>
-<span id="L425" class="LineNr">425 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
-<span id="L426" class="LineNr">426 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L427" class="LineNr">427 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
-<span id="L428" class="LineNr">428 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L429" class="LineNr">429 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
-<span id="L430" class="LineNr">430 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L431" class="LineNr">431 </span>  ]
-<span id="L432" class="LineNr">432 </span>  memory-should-contain [
-<span id="L433" class="LineNr">433 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 13</span>
-<span id="L434" class="LineNr">434 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 14</span>
-<span id="L435" class="LineNr">435 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 15</span>
-<span id="L436" class="LineNr">436 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
-<span id="L437" class="LineNr">437 </span>  ]
-<span id="L438" class="LineNr">438 </span>]
-<span id="L439" class="LineNr">439 </span>
-<span id="L440" class="LineNr">440 </span><span class="muScenario">scenario</span> remove-range-to-final [
-<span id="L441" class="LineNr">441 </span>  <span class="Constant">local-scope</span>
-<span id="L442" class="LineNr">442 </span>  <span class="Comment"># construct a duplex list with six elements [13, 14, 15, 16, 17, 18]</span>
-<span id="L443" class="LineNr">443 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 18</span>,<span class="Constant"> 0</span>
-<span id="L444" class="LineNr">444 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 17</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L445" class="LineNr">445 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 16</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L446" class="LineNr">446 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 15</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L447" class="LineNr">447 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 14</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L448" class="LineNr">448 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 13</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L449" class="LineNr">449 </span>  run [
-<span id="L450" class="LineNr">450 </span>  <span class="Conceal">¦</span> <span class="Comment"># delete 15, 16 and 17</span>
-<span id="L451" class="LineNr">451 </span>  <span class="Conceal">¦</span> <span class="Comment"># start pointer: to the second element</span>
-<span id="L452" class="LineNr">452 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L453" class="LineNr">453 </span>  <span class="Conceal">¦</span> <span class="Comment"># end pointer: to the last (sixth) element</span>
-<span id="L454" class="LineNr">454 </span>  <span class="Conceal">¦</span> end:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> list2
-<span id="L455" class="LineNr">455 </span>  <span class="Conceal">¦</span> end <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> end
-<span id="L456" class="LineNr">456 </span>  <span class="Conceal">¦</span> end <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> end
-<span id="L457" class="LineNr">457 </span>  <span class="Conceal">¦</span> end <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> end
-<span id="L458" class="LineNr">458 </span>  <span class="Conceal">¦</span> <a href='065duplex_list.mu.html#L389'>remove-between</a> list2, end
-<span id="L459" class="LineNr">459 </span>  <span class="Conceal">¦</span> <span class="Comment"># now check the list</span>
-<span id="L460" class="LineNr">460 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
-<span id="L461" class="LineNr">461 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L462" class="LineNr">462 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
-<span id="L463" class="LineNr">463 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L464" class="LineNr">464 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
-<span id="L465" class="LineNr">465 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L466" class="LineNr">466 </span>  ]
-<span id="L467" class="LineNr">467 </span>  memory-should-contain [
-<span id="L468" class="LineNr">468 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 13</span>
-<span id="L469" class="LineNr">469 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 14</span>
-<span id="L470" class="LineNr">470 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 18</span>
-<span id="L471" class="LineNr">471 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
-<span id="L472" class="LineNr">472 </span>  ]
-<span id="L473" class="LineNr">473 </span>]
-<span id="L474" class="LineNr">474 </span>
-<span id="L475" class="LineNr">475 </span><span class="muScenario">scenario</span> remove-range-empty [
-<span id="L476" class="LineNr">476 </span>  <span class="Constant">local-scope</span>
-<span id="L477" class="LineNr">477 </span>  <span class="Comment"># construct a duplex list with three elements [13, 14, 15]</span>
-<span id="L478" class="LineNr">478 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 15</span>,<span class="Constant"> 0</span>
-<span id="L479" class="LineNr">479 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 14</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L480" class="LineNr">480 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 13</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L481" class="LineNr">481 </span>  run [
-<span id="L482" class="LineNr">482 </span>  <span class="Conceal">¦</span> <span class="Comment"># delete between first and second element (i.e. nothing)</span>
-<span id="L483" class="LineNr">483 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L484" class="LineNr">484 </span>  <span class="Conceal">¦</span> <a href='065duplex_list.mu.html#L389'>remove-between</a> <a href='064list.mu.html#L6'>list</a>, list2
-<span id="L485" class="LineNr">485 </span>  <span class="Conceal">¦</span> <span class="Comment"># now check the list</span>
-<span id="L486" class="LineNr">486 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
-<span id="L487" class="LineNr">487 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L488" class="LineNr">488 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
-<span id="L489" class="LineNr">489 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L490" class="LineNr">490 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
-<span id="L491" class="LineNr">491 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L492" class="LineNr">492 </span>  ]
-<span id="L493" class="LineNr">493 </span>  <span class="Comment"># no change</span>
-<span id="L494" class="LineNr">494 </span>  memory-should-contain [
-<span id="L495" class="LineNr">495 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 13</span>
-<span id="L496" class="LineNr">496 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 14</span>
-<span id="L497" class="LineNr">497 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 15</span>
-<span id="L498" class="LineNr">498 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
-<span id="L499" class="LineNr">499 </span>  ]
-<span id="L500" class="LineNr">500 </span>]
-<span id="L501" class="LineNr">501 </span>
-<span id="L502" class="LineNr">502 </span><span class="muScenario">scenario</span> remove-range-to-end [
-<span id="L503" class="LineNr">503 </span>  <span class="Constant">local-scope</span>
-<span id="L504" class="LineNr">504 </span>  <span class="Comment"># construct a duplex list with six elements [13, 14, 15, 16, 17, 18]</span>
-<span id="L505" class="LineNr">505 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 18</span>,<span class="Constant"> 0</span>
-<span id="L506" class="LineNr">506 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 17</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L507" class="LineNr">507 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 16</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L508" class="LineNr">508 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 15</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L509" class="LineNr">509 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 14</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L510" class="LineNr">510 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 13</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L511" class="LineNr">511 </span>  run [
-<span id="L512" class="LineNr">512 </span>  <span class="Conceal">¦</span> <span class="Comment"># remove the third element and beyond</span>
-<span id="L513" class="LineNr">513 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L514" class="LineNr">514 </span>  <span class="Conceal">¦</span> <a href='065duplex_list.mu.html#L389'>remove-between</a> list2,<span class="Constant"> 0</span>
-<span id="L515" class="LineNr">515 </span>  <span class="Conceal">¦</span> <span class="Comment"># now check the list</span>
-<span id="L516" class="LineNr">516 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
-<span id="L517" class="LineNr">517 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L518" class="LineNr">518 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
-<span id="L519" class="LineNr">519 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> <a href='064list.mu.html#L6'>list</a>
-<span id="L520" class="LineNr">520 </span>  ]
-<span id="L521" class="LineNr">521 </span>  memory-should-contain [
-<span id="L522" class="LineNr">522 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 13</span>
-<span id="L523" class="LineNr">523 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 14</span>
-<span id="L524" class="LineNr">524 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
-<span id="L525" class="LineNr">525 </span>  ]
-<span id="L526" class="LineNr">526 </span>]
-<span id="L527" class="LineNr">527 </span>
-<span id="L528" class="LineNr">528 </span><span class="Comment"># insert list beginning at 'start' after 'in'</span>
-<span id="L529" class="LineNr">529 </span><span class="muRecipe">def</span> <a href='065duplex_list.mu.html#L529'>splice</a> in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem, start:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:in<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
-<span id="L530" class="LineNr">530 </span>  <span class="Constant">local-scope</span>
-<span id="L531" class="LineNr">531 </span>  <span class="Constant">load-ingredients</span>
-<span id="L532" class="LineNr">532 </span>  <span class="muControl">return-unless</span> in
-<span id="L533" class="LineNr">533 </span>  <span class="muControl">return-unless</span> start
-<span id="L534" class="LineNr">534 </span>  end:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L576'>last</a> start
-<span id="L535" class="LineNr">535 </span>  <a href='065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> in
-<span id="L536" class="LineNr">536 </span>  <span class="Delimiter">{</span>
-<span id="L537" class="LineNr">537 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='065duplex_list.mu.html#L29'>next</a>
-<span id="L538" class="LineNr">538 </span>  <span class="Conceal">¦</span> *end <span class="Special">&lt;-</span> put *end, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>, <a href='065duplex_list.mu.html#L29'>next</a>
-<span id="L539" class="LineNr">539 </span>  <span class="Conceal">¦</span> *next <span class="Special">&lt;-</span> put *next, <span class="Constant"><a href='065duplex_list.mu.html#L36'>prev</a>:offset</span>, end
-<span id="L540" class="LineNr">540 </span>  <span class="Delimiter">}</span>
-<span id="L541" class="LineNr">541 </span>  *in <span class="Special">&lt;-</span> put *in, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>, start
-<span id="L542" class="LineNr">542 </span>  *start <span class="Special">&lt;-</span> put *start, <span class="Constant"><a href='065duplex_list.mu.html#L36'>prev</a>:offset</span>, in
-<span id="L543" class="LineNr">543 </span>]
-<span id="L544" class="LineNr">544 </span>
-<span id="L545" class="LineNr">545 </span><span class="Comment"># insert contents of 'new' after 'in'</span>
-<span id="L546" class="LineNr">546 </span><span class="muRecipe">def</span> insert in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem, new:&amp;:@:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
-<span id="L547" class="LineNr">547 </span>  <span class="Constant">local-scope</span>
-<span id="L548" class="LineNr">548 </span>  <span class="Constant">load-ingredients</span>
-<span id="L549" class="LineNr">549 </span>  <span class="muControl">return-unless</span> in
-<span id="L550" class="LineNr">550 </span>  <span class="muControl">return-unless</span> new
-<span id="L551" class="LineNr">551 </span>  len:num <span class="Special">&lt;-</span> length *new
-<span id="L552" class="LineNr">552 </span>  <span class="muControl">return-unless</span> len
-<span id="L553" class="LineNr">553 </span>  curr:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> copy in
-<span id="L554" class="LineNr">554 </span>  idx:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
-<span id="L555" class="LineNr">555 </span>  <span class="Delimiter">{</span>
-<span id="L556" class="LineNr">556 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal idx, len
-<span id="L557" class="LineNr">557 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
-<span id="L558" class="LineNr">558 </span>  <span class="Conceal">¦</span> c:_elem <span class="Special">&lt;-</span> index *new, idx
-<span id="L559" class="LineNr">559 </span>  <span class="Conceal">¦</span> insert c, curr
-<span id="L560" class="LineNr">560 </span>  <span class="Conceal">¦</span> <span class="Comment"># next iter</span>
-<span id="L561" class="LineNr">561 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> curr
-<span id="L562" class="LineNr">562 </span>  <span class="Conceal">¦</span> idx <span class="Special">&lt;-</span> add idx,<span class="Constant"> 1</span>
-<span id="L563" class="LineNr">563 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
-<span id="L564" class="LineNr">564 </span>  <span class="Delimiter">}</span>
-<span id="L565" class="LineNr">565 </span>]
-<span id="L566" class="LineNr">566 </span>
-<span id="L567" class="LineNr">567 </span><span class="muRecipe">def</span> append in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem, new:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:in<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
-<span id="L568" class="LineNr">568 </span>  <span class="Constant">local-scope</span>
-<span id="L569" class="LineNr">569 </span>  <span class="Constant">load-ingredients</span>
-<span id="L570" class="LineNr">570 </span>  <a href='065duplex_list.mu.html#L576'>last</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L576'>last</a> in
-<span id="L571" class="LineNr">571 </span>  *last <span class="Special">&lt;-</span> put *last, <span class="Constant"><a href='065duplex_list.mu.html#L29'>next</a>:offset</span>, new
-<span id="L572" class="LineNr">572 </span>  <span class="muControl">return-unless</span> new
-<span id="L573" class="LineNr">573 </span>  *new <span class="Special">&lt;-</span> put *new, <span class="Constant"><a href='065duplex_list.mu.html#L36'>prev</a>:offset</span>, <a href='065duplex_list.mu.html#L576'>last</a>
-<span id="L574" class="LineNr">574 </span>]
-<span id="L575" class="LineNr">575 </span>
-<span id="L576" class="LineNr">576 </span><span class="muRecipe">def</span> <a href='065duplex_list.mu.html#L576'>last</a> in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
-<span id="L577" class="LineNr">577 </span>  <span class="Constant">local-scope</span>
-<span id="L578" class="LineNr">578 </span>  <span class="Constant">load-ingredients</span>
-<span id="L579" class="LineNr">579 </span>  result <span class="Special">&lt;-</span> copy in
-<span id="L580" class="LineNr">580 </span>  <span class="Delimiter">{</span>
-<span id="L581" class="LineNr">581 </span>  <span class="Conceal">¦</span> <a href='065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> result
-<span id="L582" class="LineNr">582 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='065duplex_list.mu.html#L29'>next</a>
-<span id="L583" class="LineNr">583 </span>  <span class="Conceal">¦</span> result <span class="Special">&lt;-</span> copy <a href='065duplex_list.mu.html#L29'>next</a>
-<span id="L584" class="LineNr">584 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
-<span id="L585" class="LineNr">585 </span>  <span class="Delimiter">}</span>
-<span id="L586" class="LineNr">586 </span>]
-<span id="L587" class="LineNr">587 </span>
-<span id="L588" class="LineNr">588 </span><span class="Comment"># does a duplex list start with a certain sequence of elements?</span>
-<span id="L589" class="LineNr">589 </span><span class="muRecipe">def</span> <a href='065duplex_list.mu.html#L589'>match</a> x:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem, y:&amp;:@:_elem<span class="muRecipe"> -&gt; </span>result:bool [
-<span id="L590" class="LineNr">590 </span>  <span class="Constant">local-scope</span>
-<span id="L591" class="LineNr">591 </span>  <span class="Constant">load-ingredients</span>
-<span id="L592" class="LineNr">592 </span>  i:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
-<span id="L593" class="LineNr">593 </span>  max:num <span class="Special">&lt;-</span> length *y
-<span id="L594" class="LineNr">594 </span>  <span class="Delimiter">{</span>
-<span id="L595" class="LineNr">595 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal i, max
-<span id="L596" class="LineNr">596 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
-<span id="L597" class="LineNr">597 </span>  <span class="Conceal">¦</span> expected:_elem <span class="Special">&lt;-</span> index *y, i
-<span id="L598" class="LineNr">598 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> x, <span class="Constant">0/no-match</span>
-<span id="L599" class="LineNr">599 </span>  <span class="Conceal">¦</span> curr:_elem <span class="Special">&lt;-</span> first x
-<span id="L600" class="LineNr">600 </span>  <span class="Conceal">¦</span> curr-matches?:bool <span class="Special">&lt;-</span> equal curr, expected
-<span id="L601" class="LineNr">601 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> curr-matches?, <span class="Constant">0/no-match</span>
-<span id="L602" class="LineNr">602 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> x
-<span id="L603" class="LineNr">603 </span>  <span class="Conceal">¦</span> i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
-<span id="L604" class="LineNr">604 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
-<span id="L605" class="LineNr">605 </span>  <span class="Delimiter">}</span>
-<span id="L606" class="LineNr">606 </span>  <span class="muControl">return</span> <span class="Constant">1/successful-match</span>
-<span id="L607" class="LineNr">607 </span>]
-<span id="L608" class="LineNr">608 </span>
-<span id="L609" class="LineNr">609 </span><span class="muScenario">scenario</span> duplex-list-match [
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-<span id="L611" class="LineNr">611 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> push <span class="Constant">97/a</span>,<span class="Constant"> 0</span>
-<span id="L612" class="LineNr">612 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push <span class="Constant">98/b</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L613" class="LineNr">613 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push <span class="Constant">99/c</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L614" class="LineNr">614 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push <span class="Constant">100/d</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L615" class="LineNr">615 </span>  run [
-<span id="L616" class="LineNr">616 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L589'>match</a> <a href='064list.mu.html#L6'>list</a>, <span class="Constant">[]</span>
-<span id="L617" class="LineNr">617 </span>  <span class="Conceal">¦</span> 11:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L589'>match</a> <a href='064list.mu.html#L6'>list</a>, <span class="Constant">[d]</span>
-<span id="L618" class="LineNr">618 </span>  <span class="Conceal">¦</span> 12:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L589'>match</a> <a href='064list.mu.html#L6'>list</a>, <span class="Constant">[dc]</span>
-<span id="L619" class="LineNr">619 </span>  <span class="Conceal">¦</span> 13:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L589'>match</a> <a href='064list.mu.html#L6'>list</a>, <span class="Constant">[dcba]</span>
-<span id="L620" class="LineNr">620 </span>  <span class="Conceal">¦</span> 14:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L589'>match</a> <a href='064list.mu.html#L6'>list</a>, <span class="Constant">[dd]</span>
-<span id="L621" class="LineNr">621 </span>  <span class="Conceal">¦</span> 15:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L589'>match</a> <a href='064list.mu.html#L6'>list</a>, <span class="Constant">[dcbax]</span>
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-<span id="L623" class="LineNr">623 </span>  memory-should-contain [
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-<span id="L625" class="LineNr">625 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># matches [d]</span>
-<span id="L626" class="LineNr">626 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># matches [dc]</span>
-<span id="L627" class="LineNr">627 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># matches [dcba]</span>
-<span id="L628" class="LineNr">628 </span>  <span class="Conceal">¦</span><span class="Constant"> 14</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># does not match [dd]</span>
-<span id="L629" class="LineNr">629 </span>  <span class="Conceal">¦</span><span class="Constant"> 15</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># does not match [dcbax]</span>
-<span id="L630" class="LineNr">630 </span>  ]
-<span id="L631" class="LineNr">631 </span>]
-<span id="L632" class="LineNr">632 </span>
-<span id="L633" class="LineNr">633 </span><span class="Comment"># helper for debugging</span>
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-<span id="L635" class="LineNr">635 </span>  <span class="Constant">local-scope</span>
-<span id="L636" class="LineNr">636 </span>  <span class="Constant">load-ingredients</span>
-<span id="L637" class="LineNr">637 </span>  $print x, <span class="Constant">[: ]</span>
-<span id="L638" class="LineNr">638 </span>  <span class="Delimiter">{</span>
-<span id="L639" class="LineNr">639 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> x
-<span id="L640" class="LineNr">640 </span>  <span class="Conceal">¦</span> c:_elem <span class="Special">&lt;-</span> get *x, <span class="Constant">value:offset</span>
-<span id="L641" class="LineNr">641 </span>  <span class="Conceal">¦</span> $print c, <span class="Constant">[ ]</span>
-<span id="L642" class="LineNr">642 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> x
-<span id="L643" class="LineNr">643 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
-<span id="L644" class="LineNr">644 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> is-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
-<span id="L645" class="LineNr">645 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-newline?
-<span id="L646" class="LineNr">646 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> $print <span class="Constant">10/newline</span>
-<span id="L647" class="LineNr">647 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> $print x, <span class="Constant">[: ]</span>
-<span id="L648" class="LineNr">648 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
-<span id="L649" class="LineNr">649 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
-<span id="L650" class="LineNr">650 </span>  <span class="Delimiter">}</span>
-<span id="L651" class="LineNr">651 </span>  $print <span class="Constant">10/newline</span>, <span class="Constant">[---]</span>, <span class="Constant">10/newline</span>
-<span id="L652" class="LineNr">652 </span>]
-<span id="L653" class="LineNr">653 </span>
-<span id="L654" class="LineNr">654 </span><span class="muScenario">scenario</span> stash-duplex-list [
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-<span id="L656" class="LineNr">656 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 1</span>,<span class="Constant"> 0</span>
-<span id="L657" class="LineNr">657 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 2</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L658" class="LineNr">658 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L659" class="LineNr">659 </span>  run [
-<span id="L660" class="LineNr">660 </span>  <span class="Conceal">¦</span> stash <span class="Constant">[list:]</span>, <a href='064list.mu.html#L6'>list</a>
-<span id="L661" class="LineNr">661 </span>  ]
-<span id="L662" class="LineNr">662 </span>  trace-should-contain [
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-<span id="L664" class="LineNr">664 </span>  ]
-<span id="L665" class="LineNr">665 </span>]
-<span id="L666" class="LineNr">666 </span>
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-<span id="L668" class="LineNr">668 </span>  <span class="Constant">local-scope</span>
-<span id="L669" class="LineNr">669 </span>  <span class="Constant">load-ingredients</span>
-<span id="L670" class="LineNr">670 </span>  buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char <span class="Special">&lt;-</span> <a href='061text.mu.html#L125'>new-buffer</a><span class="Constant"> 80</span>
-<span id="L671" class="LineNr">671 </span>  buf <span class="Special">&lt;-</span> to-buffer in, buf
-<span id="L672" class="LineNr">672 </span>  result <span class="Special">&lt;-</span> <a href='061text.mu.html#L338'>buffer-to-array</a> buf
-<span id="L673" class="LineNr">673 </span>]
-<span id="L674" class="LineNr">674 </span>
-<span id="L675" class="LineNr">675 </span><span class="Comment"># variant of 'to-text' which stops printing after a few elements (and so is robust to cycles)</span>
-<span id="L676" class="LineNr">676 </span><span class="muRecipe">def</span> to-text-line in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>result:text [
-<span id="L677" class="LineNr">677 </span>  <span class="Constant">local-scope</span>
-<span id="L678" class="LineNr">678 </span>  <span class="Constant">load-ingredients</span>
-<span id="L679" class="LineNr">679 </span>  buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char <span class="Special">&lt;-</span> <a href='061text.mu.html#L125'>new-buffer</a><span class="Constant"> 80</span>
-<span id="L680" class="LineNr">680 </span>  buf <span class="Special">&lt;-</span> to-buffer in, buf,<span class="Constant"> 6</span>  <span class="Comment"># max elements to display</span>
-<span id="L681" class="LineNr">681 </span>  result <span class="Special">&lt;-</span> <a href='061text.mu.html#L338'>buffer-to-array</a> buf
-<span id="L682" class="LineNr">682 </span>]
-<span id="L683" class="LineNr">683 </span>
-<span id="L684" class="LineNr">684 </span><span class="muRecipe">def</span> to-buffer in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem, buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char<span class="muRecipe"> -&gt; </span>buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char [
-<span id="L685" class="LineNr">685 </span>  <span class="Constant">local-scope</span>
-<span id="L686" class="LineNr">686 </span>  <span class="Constant">load-ingredients</span>
-<span id="L687" class="LineNr">687 </span>  <span class="Delimiter">{</span>
-<span id="L688" class="LineNr">688 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> in
-<span id="L689" class="LineNr">689 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> append buf, <span class="Constant">[[]</span>]
-<span id="L690" class="LineNr">690 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
-<span id="L691" class="LineNr">691 </span>  <span class="Delimiter">}</span>
-<span id="L692" class="LineNr">692 </span>  <span class="Comment"># append in.value to buf</span>
-<span id="L693" class="LineNr">693 </span>  val:_elem <span class="Special">&lt;-</span> get *in, <span class="Constant">value:offset</span>
-<span id="L694" class="LineNr">694 </span>  buf <span class="Special">&lt;-</span> append buf, val
-<span id="L695" class="LineNr">695 </span>  <span class="Comment"># now prepare next</span>
-<span id="L696" class="LineNr">696 </span>  <a href='065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L29'>next</a> in
-<span id="L697" class="LineNr">697 </span>  nextn:num <span class="Special">&lt;-</span> copy <a href='065duplex_list.mu.html#L29'>next</a>
-<span id="L698" class="LineNr">698 </span>  <span class="muControl">return-unless</span> <a href='065duplex_list.mu.html#L29'>next</a>
-<span id="L699" class="LineNr">699 </span>  buf <span class="Special">&lt;-</span> append buf, <span class="Constant">[ &lt;-&gt; ]</span>
-<span id="L700" class="LineNr">700 </span>  <span class="Comment"># and recurse</span>
-<span id="L701" class="LineNr">701 </span>  remaining:num, optional-ingredient-found?:bool <span class="Special">&lt;-</span> <span class="Constant">next-ingredient</span>
-<span id="L702" class="LineNr">702 </span>  <span class="Delimiter">{</span>
-<span id="L703" class="LineNr">703 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> optional-ingredient-found?
-<span id="L704" class="LineNr">704 </span>  <span class="Conceal">¦</span> <span class="Comment"># unlimited recursion</span>
-<span id="L705" class="LineNr">705 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> to-buffer <a href='065duplex_list.mu.html#L29'>next</a>, buf
-<span id="L706" class="LineNr">706 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
-<span id="L707" class="LineNr">707 </span>  <span class="Delimiter">}</span>
-<span id="L708" class="LineNr">708 </span>  <span class="Delimiter">{</span>
-<span id="L709" class="LineNr">709 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> remaining
-<span id="L710" class="LineNr">710 </span>  <span class="Conceal">¦</span> <span class="Comment"># limited recursion</span>
-<span id="L711" class="LineNr">711 </span>  <span class="Conceal">¦</span> remaining <span class="Special">&lt;-</span> subtract remaining,<span class="Constant"> 1</span>
-<span id="L712" class="LineNr">712 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> to-buffer <a href='065duplex_list.mu.html#L29'>next</a>, buf, remaining
-<span id="L713" class="LineNr">713 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
-<span id="L714" class="LineNr">714 </span>  <span class="Delimiter">}</span>
-<span id="L715" class="LineNr">715 </span>  <span class="Comment"># past recursion depth; insert ellipses and stop</span>
-<span id="L716" class="LineNr">716 </span>  append buf, <span class="Constant">[...]</span>
-<span id="L717" class="LineNr">717 </span>]
-<span id="L718" class="LineNr">718 </span>
-<span id="L719" class="LineNr">719 </span><span class="muScenario">scenario</span> stash-empty-duplex-list [
-<span id="L720" class="LineNr">720 </span>  <span class="Constant">local-scope</span>
-<span id="L721" class="LineNr">721 </span>  x:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
-<span id="L722" class="LineNr">722 </span>  run [
-<span id="L723" class="LineNr">723 </span>  <span class="Conceal">¦</span> stash x
-<span id="L724" class="LineNr">724 </span>  ]
-<span id="L725" class="LineNr">725 </span>  trace-should-contain [
-<span id="L726" class="LineNr">726 </span>  <span class="Conceal">¦</span> app: <span class="Constant">[]</span>
-<span id="L727" class="LineNr">727 </span>  ]
-<span id="L728" class="LineNr">728 </span>]
+<span id="L9" class="LineNr">  9 </span><span class="muRecipe">def</span> push x:_elem, in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:result<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
+<span id="L10" class="LineNr"> 10 </span>  <span class="Constant">local-scope</span>
+<span id="L11" class="LineNr"> 11 </span>  <span class="Constant">load-ingredients</span>
+<span id="L12" class="LineNr"> 12 </span>  result:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> new <span class="Delimiter">{</span>(duplex-list _elem): type<span class="Delimiter">}</span>
+<span id="L13" class="LineNr"> 13 </span>  *result <span class="Special">&lt;-</span> merge x, in,<span class="Constant"> 0</span>
+<span id="L14" class="LineNr"> 14 </span>  <span class="muControl">return-unless</span> in
+<span id="L15" class="LineNr"> 15 </span>  put *in, <span class="Constant"><a href='065duplex_list.mu.html#L32'>prev</a>:offset</span>, result
+<span id="L16" class="LineNr"> 16 </span>]
+<span id="L17" class="LineNr"> 17 </span>
+<span id="L18" class="LineNr"> 18 </span><span class="muRecipe">def</span> first in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>result:_elem [
+<span id="L19" class="LineNr"> 19 </span>  <span class="Constant">local-scope</span>
+<span id="L20" class="LineNr"> 20 </span>  <span class="Constant">load-ingredients</span>
+<span id="L21" class="LineNr"> 21 </span>  <span class="muControl">return-unless</span> in,<span class="Constant"> 0</span>
+<span id="L22" class="LineNr"> 22 </span>  result <span class="Special">&lt;-</span> get *in, <span class="Constant">value:offset</span>
+<span id="L23" class="LineNr"> 23 </span>]
+<span id="L24" class="LineNr"> 24 </span>
+<span id="L25" class="LineNr"> 25 </span><span class="muRecipe">def</span> <a href='065duplex_list.mu.html#L25'>next</a> in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:in [
+<span id="L26" class="LineNr"> 26 </span>  <span class="Constant">local-scope</span>
+<span id="L27" class="LineNr"> 27 </span>  <span class="Constant">load-ingredients</span>
+<span id="L28" class="LineNr"> 28 </span>  <span class="muControl">return-unless</span> in,<span class="Constant"> 0</span>
+<span id="L29" class="LineNr"> 29 </span>  result <span class="Special">&lt;-</span> get *in, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>
+<span id="L30" class="LineNr"> 30 </span>]
+<span id="L31" class="LineNr"> 31 </span>
+<span id="L32" class="LineNr"> 32 </span><span class="muRecipe">def</span> <a href='065duplex_list.mu.html#L32'>prev</a> in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:in [
+<span id="L33" class="LineNr"> 33 </span>  <span class="Constant">local-scope</span>
+<span id="L34" class="LineNr"> 34 </span>  <span class="Constant">load-ingredients</span>
+<span id="L35" class="LineNr"> 35 </span>  <span class="muControl">return-unless</span> in,<span class="Constant"> 0</span>
+<span id="L36" class="LineNr"> 36 </span>  result <span class="Special">&lt;-</span> get *in, <span class="Constant"><a href='065duplex_list.mu.html#L32'>prev</a>:offset</span>
+<span id="L37" class="LineNr"> 37 </span>  <span class="muControl">return</span> result
+<span id="L38" class="LineNr"> 38 </span>]
+<span id="L39" class="LineNr"> 39 </span>
+<span id="L40" class="LineNr"> 40 </span><span class="muScenario">scenario</span> duplex-list-handling [
+<span id="L41" class="LineNr"> 41 </span>  run [
+<span id="L42" class="LineNr"> 42 </span>  <span class="Conceal">¦</span> <span class="Constant">local-scope</span>
+<span id="L43" class="LineNr"> 43 </span>  <span class="Conceal">¦</span> <span class="Comment"># reserve locations 0-9 to check for missing null check</span>
+<span id="L44" class="LineNr"> 44 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> copy<span class="Constant"> 34</span>
+<span id="L45" class="LineNr"> 45 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> copy<span class="Constant"> 35</span>
+<span id="L46" class="LineNr"> 46 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L47" class="LineNr"> 47 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L48" class="LineNr"> 48 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L49" class="LineNr"> 49 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L50" class="LineNr"> 50 </span>  <span class="Conceal">¦</span> 20:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L51" class="LineNr"> 51 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L52" class="LineNr"> 52 </span>  <span class="Conceal">¦</span> 21:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L53" class="LineNr"> 53 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L54" class="LineNr"> 54 </span>  <span class="Conceal">¦</span> 22:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L55" class="LineNr"> 55 </span>  <span class="Conceal">¦</span> 30:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L56" class="LineNr"> 56 </span>  <span class="Conceal">¦</span> 31:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first 30:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span>
+<span id="L57" class="LineNr"> 57 </span>  <span class="Conceal">¦</span> 32:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> 30:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span>
+<span id="L58" class="LineNr"> 58 </span>  <span class="Conceal">¦</span> 33:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> 30:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span>
+<span id="L59" class="LineNr"> 59 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L60" class="LineNr"> 60 </span>  <span class="Conceal">¦</span> 40:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L61" class="LineNr"> 61 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L62" class="LineNr"> 62 </span>  <span class="Conceal">¦</span> 41:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L63" class="LineNr"> 63 </span>  <span class="Conceal">¦</span> 50:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
+<span id="L64" class="LineNr"> 64 </span>  ]
+<span id="L65" class="LineNr"> 65 </span>  memory-should-contain [
+<span id="L66" class="LineNr"> 66 </span>  <span class="Conceal">¦</span><span class="Constant"> 0</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no modifications to null pointers</span>
+<span id="L67" class="LineNr"> 67 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 34</span>
+<span id="L68" class="LineNr"> 68 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 35</span>
+<span id="L69" class="LineNr"> 69 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
+<span id="L70" class="LineNr"> 70 </span>  <span class="Conceal">¦</span><span class="Constant"> 21</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
+<span id="L71" class="LineNr"> 71 </span>  <span class="Conceal">¦</span><span class="Constant"> 22</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L72" class="LineNr"> 72 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># null</span>
+<span id="L73" class="LineNr"> 73 </span>  <span class="Conceal">¦</span><span class="Constant"> 31</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># first of null</span>
+<span id="L74" class="LineNr"> 74 </span>  <span class="Conceal">¦</span><span class="Constant"> 32</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># next of null</span>
+<span id="L75" class="LineNr"> 75 </span>  <span class="Conceal">¦</span><span class="Constant"> 33</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># prev of null</span>
+<span id="L76" class="LineNr"> 76 </span>  <span class="Conceal">¦</span><span class="Constant"> 40</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># then start scanning prev</span>
+<span id="L77" class="LineNr"> 77 </span>  <span class="Conceal">¦</span><span class="Constant"> 41</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
+<span id="L78" class="LineNr"> 78 </span>  <span class="Conceal">¦</span><span class="Constant"> 50</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
+<span id="L79" class="LineNr"> 79 </span>  ]
+<span id="L80" class="LineNr"> 80 </span>]
+<span id="L81" class="LineNr"> 81 </span>
+<span id="L82" class="LineNr"> 82 </span><span class="muRecipe">def</span> length l:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>result:num [
+<span id="L83" class="LineNr"> 83 </span>  <span class="Constant">local-scope</span>
+<span id="L84" class="LineNr"> 84 </span>  <span class="Constant">load-ingredients</span>
+<span id="L85" class="LineNr"> 85 </span>  result <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
+<span id="L86" class="LineNr"> 86 </span>  <span class="Delimiter">{</span>
+<span id="L87" class="LineNr"> 87 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> l
+<span id="L88" class="LineNr"> 88 </span>  <span class="Conceal">¦</span> result <span class="Special">&lt;-</span> add result,<span class="Constant"> 1</span>
+<span id="L89" class="LineNr"> 89 </span>  <span class="Conceal">¦</span> l <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> l
+<span id="L90" class="LineNr"> 90 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L91" class="LineNr"> 91 </span>  <span class="Delimiter">}</span>
+<span id="L92" class="LineNr"> 92 </span>]
+<span id="L93" class="LineNr"> 93 </span>
+<span id="L94" class="LineNr"> 94 </span><span class="Comment"># insert 'x' after 'in'</span>
+<span id="L95" class="LineNr"> 95 </span><span class="muRecipe">def</span> insert x:_elem, in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
+<span id="L96" class="LineNr"> 96 </span>  <span class="Constant">local-scope</span>
+<span id="L97" class="LineNr"> 97 </span>  <span class="Constant">load-ingredients</span>
+<span id="L98" class="LineNr"> 98 </span>  new-node:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> new <span class="Delimiter">{</span>(duplex-list _elem): type<span class="Delimiter">}</span>
+<span id="L99" class="LineNr"> 99 </span>  *new-node <span class="Special">&lt;-</span> put *new-node, <span class="Constant">value:offset</span>, x
+<span id="L100" class="LineNr">100 </span>  <span class="Comment"># save old next before changing it</span>
+<span id="L101" class="LineNr">101 </span>  next-node:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> get *in, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>
+<span id="L102" class="LineNr">102 </span>  *in <span class="Special">&lt;-</span> put *in, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>, new-node
+<span id="L103" class="LineNr">103 </span>  *new-node <span class="Special">&lt;-</span> put *new-node, <span class="Constant"><a href='065duplex_list.mu.html#L32'>prev</a>:offset</span>, in
+<span id="L104" class="LineNr">104 </span>  *new-node <span class="Special">&lt;-</span> put *new-node, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>, next-node
+<span id="L105" class="LineNr">105 </span>  <span class="muControl">return-unless</span> next-node
+<span id="L106" class="LineNr">106 </span>  *next-node <span class="Special">&lt;-</span> put *next-node, <span class="Constant"><a href='065duplex_list.mu.html#L32'>prev</a>:offset</span>, new-node
+<span id="L107" class="LineNr">107 </span>]
+<span id="L108" class="LineNr">108 </span>
+<span id="L109" class="LineNr">109 </span><span class="muScenario">scenario</span> inserting-into-duplex-list [
+<span id="L110" class="LineNr">110 </span>  <span class="Constant">local-scope</span>
+<span id="L111" class="LineNr">111 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L112" class="LineNr">112 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L113" class="LineNr">113 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L114" class="LineNr">114 </span>  run [
+<span id="L115" class="LineNr">115 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># inside list</span>
+<span id="L116" class="LineNr">116 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, list2
+<span id="L117" class="LineNr">117 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
+<span id="L118" class="LineNr">118 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L119" class="LineNr">119 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L120" class="LineNr">120 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L121" class="LineNr">121 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L122" class="LineNr">122 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L123" class="LineNr">123 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L124" class="LineNr">124 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L125" class="LineNr">125 </span>  <span class="Conceal">¦</span> 13:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L126" class="LineNr">126 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L127" class="LineNr">127 </span>  <span class="Conceal">¦</span> 20:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L128" class="LineNr">128 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L129" class="LineNr">129 </span>  <span class="Conceal">¦</span> 21:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L130" class="LineNr">130 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L131" class="LineNr">131 </span>  <span class="Conceal">¦</span> 22:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L132" class="LineNr">132 </span>  <span class="Conceal">¦</span> 30:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
+<span id="L133" class="LineNr">133 </span>  ]
+<span id="L134" class="LineNr">134 </span>  memory-should-contain [
+<span id="L135" class="LineNr">135 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
+<span id="L136" class="LineNr">136 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
+<span id="L137" class="LineNr">137 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
+<span id="L138" class="LineNr">138 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L139" class="LineNr">139 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># then prev</span>
+<span id="L140" class="LineNr">140 </span>  <span class="Conceal">¦</span><span class="Constant"> 21</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
+<span id="L141" class="LineNr">141 </span>  <span class="Conceal">¦</span><span class="Constant"> 22</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
+<span id="L142" class="LineNr">142 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
+<span id="L143" class="LineNr">143 </span>  ]
+<span id="L144" class="LineNr">144 </span>]
+<span id="L145" class="LineNr">145 </span>
+<span id="L146" class="LineNr">146 </span><span class="muScenario">scenario</span> inserting-at-end-of-duplex-list [
+<span id="L147" class="LineNr">147 </span>  <span class="Constant">local-scope</span>
+<span id="L148" class="LineNr">148 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L149" class="LineNr">149 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L150" class="LineNr">150 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L151" class="LineNr">151 </span>  run [
+<span id="L152" class="LineNr">152 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># inside list</span>
+<span id="L153" class="LineNr">153 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2  <span class="Comment"># now at end of list</span>
+<span id="L154" class="LineNr">154 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, list2
+<span id="L155" class="LineNr">155 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
+<span id="L156" class="LineNr">156 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L157" class="LineNr">157 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L158" class="LineNr">158 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L159" class="LineNr">159 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L160" class="LineNr">160 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L161" class="LineNr">161 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L162" class="LineNr">162 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L163" class="LineNr">163 </span>  <span class="Conceal">¦</span> 13:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L164" class="LineNr">164 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L165" class="LineNr">165 </span>  <span class="Conceal">¦</span> 20:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L166" class="LineNr">166 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L167" class="LineNr">167 </span>  <span class="Conceal">¦</span> 21:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L168" class="LineNr">168 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L169" class="LineNr">169 </span>  <span class="Conceal">¦</span> 22:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L170" class="LineNr">170 </span>  <span class="Conceal">¦</span> 30:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
+<span id="L171" class="LineNr">171 </span>  ]
+<span id="L172" class="LineNr">172 </span>  memory-should-contain [
+<span id="L173" class="LineNr">173 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
+<span id="L174" class="LineNr">174 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
+<span id="L175" class="LineNr">175 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L176" class="LineNr">176 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
+<span id="L177" class="LineNr">177 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>  <span class="Comment"># then prev</span>
+<span id="L178" class="LineNr">178 </span>  <span class="Conceal">¦</span><span class="Constant"> 21</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
+<span id="L179" class="LineNr">179 </span>  <span class="Conceal">¦</span><span class="Constant"> 22</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
+<span id="L180" class="LineNr">180 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
+<span id="L181" class="LineNr">181 </span>  ]
+<span id="L182" class="LineNr">182 </span>]
+<span id="L183" class="LineNr">183 </span>
+<span id="L184" class="LineNr">184 </span><span class="muScenario">scenario</span> inserting-after-start-of-duplex-list [
+<span id="L185" class="LineNr">185 </span>  <span class="Constant">local-scope</span>
+<span id="L186" class="LineNr">186 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L187" class="LineNr">187 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L188" class="LineNr">188 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L189" class="LineNr">189 </span>  run [
+<span id="L190" class="LineNr">190 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> insert<span class="Constant"> 6</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L191" class="LineNr">191 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
+<span id="L192" class="LineNr">192 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L193" class="LineNr">193 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L194" class="LineNr">194 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L195" class="LineNr">195 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L196" class="LineNr">196 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L197" class="LineNr">197 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L198" class="LineNr">198 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L199" class="LineNr">199 </span>  <span class="Conceal">¦</span> 13:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L200" class="LineNr">200 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L201" class="LineNr">201 </span>  <span class="Conceal">¦</span> 20:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L202" class="LineNr">202 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L203" class="LineNr">203 </span>  <span class="Conceal">¦</span> 21:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L204" class="LineNr">204 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L205" class="LineNr">205 </span>  <span class="Conceal">¦</span> 22:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L206" class="LineNr">206 </span>  <span class="Conceal">¦</span> 30:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
+<span id="L207" class="LineNr">207 </span>  ]
+<span id="L208" class="LineNr">208 </span>  memory-should-contain [
+<span id="L209" class="LineNr">209 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next</span>
+<span id="L210" class="LineNr">210 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>  <span class="Comment"># inserted element</span>
+<span id="L211" class="LineNr">211 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
+<span id="L212" class="LineNr">212 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L213" class="LineNr">213 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># then prev</span>
+<span id="L214" class="LineNr">214 </span>  <span class="Conceal">¦</span><span class="Constant"> 21</span> <span class="Special">&lt;-</span><span class="Constant"> 6</span>
+<span id="L215" class="LineNr">215 </span>  <span class="Conceal">¦</span><span class="Constant"> 22</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>
+<span id="L216" class="LineNr">216 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
+<span id="L217" class="LineNr">217 </span>  ]
+<span id="L218" class="LineNr">218 </span>]
+<span id="L219" class="LineNr">219 </span>
+<span id="L220" class="LineNr">220 </span><span class="Comment"># remove 'x' from its surrounding list 'in'</span>
+<span id="L221" class="LineNr">221 </span><span class="Comment">#</span>
+<span id="L222" class="LineNr">222 </span><span class="Comment"># Returns null if and only if list is empty. Beware: in that case any other</span>
+<span id="L223" class="LineNr">223 </span><span class="Comment"># pointers to the head are now invalid.</span>
+<span id="L224" class="LineNr">224 </span><span class="muRecipe">def</span> remove x:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:in, in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
+<span id="L225" class="LineNr">225 </span>  <span class="Constant">local-scope</span>
+<span id="L226" class="LineNr">226 </span>  <span class="Constant">load-ingredients</span>
+<span id="L227" class="LineNr">227 </span>  <span class="Comment"># if 'x' is null, return</span>
+<span id="L228" class="LineNr">228 </span>  <span class="muControl">return-unless</span> x
+<span id="L229" class="LineNr">229 </span>  next-node:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> get *x, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>
+<span id="L230" class="LineNr">230 </span>  prev-node:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> get *x, <span class="Constant"><a href='065duplex_list.mu.html#L32'>prev</a>:offset</span>
+<span id="L231" class="LineNr">231 </span>  <span class="Comment"># null x's pointers</span>
+<span id="L232" class="LineNr">232 </span>  *x <span class="Special">&lt;-</span> put *x, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>,<span class="Constant"> 0</span>
+<span id="L233" class="LineNr">233 </span>  *x <span class="Special">&lt;-</span> put *x, <span class="Constant"><a href='065duplex_list.mu.html#L32'>prev</a>:offset</span>,<span class="Constant"> 0</span>
+<span id="L234" class="LineNr">234 </span>  <span class="Comment"># if next-node is not null, set its prev pointer</span>
+<span id="L235" class="LineNr">235 </span>  <span class="Delimiter">{</span>
+<span id="L236" class="LineNr">236 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> next-node
+<span id="L237" class="LineNr">237 </span>  <span class="Conceal">¦</span> *next-node <span class="Special">&lt;-</span> put *next-node, <span class="Constant"><a href='065duplex_list.mu.html#L32'>prev</a>:offset</span>, prev-node
+<span id="L238" class="LineNr">238 </span>  <span class="Delimiter">}</span>
+<span id="L239" class="LineNr">239 </span>  <span class="Comment"># if prev-node is not null, set its next pointer and return</span>
+<span id="L240" class="LineNr">240 </span>  <span class="Delimiter">{</span>
+<span id="L241" class="LineNr">241 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> prev-node
+<span id="L242" class="LineNr">242 </span>  <span class="Conceal">¦</span> *prev-node <span class="Special">&lt;-</span> put *prev-node, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>, next-node
+<span id="L243" class="LineNr">243 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
+<span id="L244" class="LineNr">244 </span>  <span class="Delimiter">}</span>
+<span id="L245" class="LineNr">245 </span>  <span class="Comment"># if prev-node is null, then we removed the head node at 'in'</span>
+<span id="L246" class="LineNr">246 </span>  <span class="Comment"># return the new head rather than the old 'in'</span>
+<span id="L247" class="LineNr">247 </span>  <span class="muControl">return</span> next-node
+<span id="L248" class="LineNr">248 </span>]
+<span id="L249" class="LineNr">249 </span>
+<span id="L250" class="LineNr">250 </span><span class="muScenario">scenario</span> removing-from-duplex-list [
+<span id="L251" class="LineNr">251 </span>  <span class="Constant">local-scope</span>
+<span id="L252" class="LineNr">252 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L253" class="LineNr">253 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L254" class="LineNr">254 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L255" class="LineNr">255 </span>  run [
+<span id="L256" class="LineNr">256 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># second element</span>
+<span id="L257" class="LineNr">257 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove list2, <a href='064list.mu.html#L6'>list</a>
+<span id="L258" class="LineNr">258 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal list2,<span class="Constant"> 0</span>
+<span id="L259" class="LineNr">259 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
+<span id="L260" class="LineNr">260 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L261" class="LineNr">261 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L262" class="LineNr">262 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L263" class="LineNr">263 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L264" class="LineNr">264 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L265" class="LineNr">265 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L266" class="LineNr">266 </span>  <span class="Conceal">¦</span> 30:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L267" class="LineNr">267 </span>  <span class="Conceal">¦</span> 40:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
+<span id="L268" class="LineNr">268 </span>  ]
+<span id="L269" class="LineNr">269 </span>  memory-should-contain [
+<span id="L270" class="LineNr">270 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># remove returned non-null</span>
+<span id="L271" class="LineNr">271 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next, skipping deleted element</span>
+<span id="L272" class="LineNr">272 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L273" class="LineNr">273 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
+<span id="L274" class="LineNr">274 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># prev of final element</span>
+<span id="L275" class="LineNr">275 </span>  <span class="Conceal">¦</span><span class="Constant"> 40</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
+<span id="L276" class="LineNr">276 </span>  ]
+<span id="L277" class="LineNr">277 </span>]
+<span id="L278" class="LineNr">278 </span>
+<span id="L279" class="LineNr">279 </span><span class="muScenario">scenario</span> removing-from-start-of-duplex-list [
+<span id="L280" class="LineNr">280 </span>  <span class="Constant">local-scope</span>
+<span id="L281" class="LineNr">281 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L282" class="LineNr">282 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L283" class="LineNr">283 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L284" class="LineNr">284 </span>  run [
+<span id="L285" class="LineNr">285 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove <a href='064list.mu.html#L6'>list</a>, <a href='064list.mu.html#L6'>list</a>
+<span id="L286" class="LineNr">286 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
+<span id="L287" class="LineNr">287 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L288" class="LineNr">288 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L289" class="LineNr">289 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L290" class="LineNr">290 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L291" class="LineNr">291 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L292" class="LineNr">292 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L293" class="LineNr">293 </span>  <span class="Conceal">¦</span> 30:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L294" class="LineNr">294 </span>  <span class="Conceal">¦</span> 40:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
+<span id="L295" class="LineNr">295 </span>  ]
+<span id="L296" class="LineNr">296 </span>  memory-should-contain [
+<span id="L297" class="LineNr">297 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># scanning next, skipping deleted element</span>
+<span id="L298" class="LineNr">298 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 3</span>
+<span id="L299" class="LineNr">299 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
+<span id="L300" class="LineNr">300 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>  <span class="Comment"># prev of final element</span>
+<span id="L301" class="LineNr">301 </span>  <span class="Conceal">¦</span><span class="Constant"> 40</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
+<span id="L302" class="LineNr">302 </span>  ]
+<span id="L303" class="LineNr">303 </span>]
+<span id="L304" class="LineNr">304 </span>
+<span id="L305" class="LineNr">305 </span><span class="muScenario">scenario</span> removing-from-end-of-duplex-list [
+<span id="L306" class="LineNr">306 </span>  <span class="Constant">local-scope</span>
+<span id="L307" class="LineNr">307 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L308" class="LineNr">308 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L309" class="LineNr">309 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L310" class="LineNr">310 </span>  run [
+<span id="L311" class="LineNr">311 </span>  <span class="Conceal">¦</span> <span class="Comment"># delete last element</span>
+<span id="L312" class="LineNr">312 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L313" class="LineNr">313 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L314" class="LineNr">314 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove list2, <a href='064list.mu.html#L6'>list</a>
+<span id="L315" class="LineNr">315 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal list2,<span class="Constant"> 0</span>
+<span id="L316" class="LineNr">316 </span>  <span class="Conceal">¦</span> <span class="Comment"># check structure like before</span>
+<span id="L317" class="LineNr">317 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L318" class="LineNr">318 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L319" class="LineNr">319 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L320" class="LineNr">320 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L321" class="LineNr">321 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L322" class="LineNr">322 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L32'>prev</a> list2
+<span id="L323" class="LineNr">323 </span>  <span class="Conceal">¦</span> 30:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> first list2
+<span id="L324" class="LineNr">324 </span>  <span class="Conceal">¦</span> 40:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> equal <a href='064list.mu.html#L6'>list</a>, list2
+<span id="L325" class="LineNr">325 </span>  ]
+<span id="L326" class="LineNr">326 </span>  memory-should-contain [
+<span id="L327" class="LineNr">327 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># remove returned non-null</span>
+<span id="L328" class="LineNr">328 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># scanning next, skipping deleted element</span>
+<span id="L329" class="LineNr">329 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 4</span>
+<span id="L330" class="LineNr">330 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
+<span id="L331" class="LineNr">331 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 5</span>  <span class="Comment"># prev of final element</span>
+<span id="L332" class="LineNr">332 </span>  <span class="Conceal">¦</span><span class="Constant"> 40</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># list back at start</span>
+<span id="L333" class="LineNr">333 </span>  ]
+<span id="L334" class="LineNr">334 </span>]
+<span id="L335" class="LineNr">335 </span>
+<span id="L336" class="LineNr">336 </span><span class="muScenario">scenario</span> removing-from-singleton-duplex-list [
+<span id="L337" class="LineNr">337 </span>  <span class="Constant">local-scope</span>
+<span id="L338" class="LineNr">338 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L339" class="LineNr">339 </span>  run [
+<span id="L340" class="LineNr">340 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove <a href='064list.mu.html#L6'>list</a>, <a href='064list.mu.html#L6'>list</a>
+<span id="L341" class="LineNr">341 </span>  <span class="Conceal">¦</span> 1:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> copy <a href='064list.mu.html#L6'>list</a>
+<span id="L342" class="LineNr">342 </span>  ]
+<span id="L343" class="LineNr">343 </span>  memory-should-contain [
+<span id="L344" class="LineNr">344 </span>  <span class="Conceal">¦</span><span class="Constant"> 1</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># back to an empty list</span>
+<span id="L345" class="LineNr">345 </span>  ]
+<span id="L346" class="LineNr">346 </span>]
+<span id="L347" class="LineNr">347 </span>
+<span id="L348" class="LineNr">348 </span><span class="muRecipe">def</span> remove x:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:in, n:num, in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
+<span id="L349" class="LineNr">349 </span>  <span class="Constant">local-scope</span>
+<span id="L350" class="LineNr">350 </span>  <span class="Constant">load-ingredients</span>
+<span id="L351" class="LineNr">351 </span>  i:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
+<span id="L352" class="LineNr">352 </span>  curr:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> copy x
+<span id="L353" class="LineNr">353 </span>  <span class="Delimiter">{</span>
+<span id="L354" class="LineNr">354 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal i, n
+<span id="L355" class="LineNr">355 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L356" class="LineNr">356 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
+<span id="L357" class="LineNr">357 </span>  <span class="Conceal">¦</span> <a href='065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> curr
+<span id="L358" class="LineNr">358 </span>  <span class="Conceal">¦</span> in <span class="Special">&lt;-</span> remove curr, in
+<span id="L359" class="LineNr">359 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> copy <a href='065duplex_list.mu.html#L25'>next</a>
+<span id="L360" class="LineNr">360 </span>  <span class="Conceal">¦</span> i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
+<span id="L361" class="LineNr">361 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L362" class="LineNr">362 </span>  <span class="Delimiter">}</span>
+<span id="L363" class="LineNr">363 </span>]
+<span id="L364" class="LineNr">364 </span>
+<span id="L365" class="LineNr">365 </span><span class="muScenario">scenario</span> removing-multiple-from-duplex-list [
+<span id="L366" class="LineNr">366 </span>  <span class="Constant">local-scope</span>
+<span id="L367" class="LineNr">367 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>,<span class="Constant"> 0</span>
+<span id="L368" class="LineNr">368 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 4</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L369" class="LineNr">369 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 5</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L370" class="LineNr">370 </span>  run [
+<span id="L371" class="LineNr">371 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>  <span class="Comment"># second element</span>
+<span id="L372" class="LineNr">372 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> remove list2,<span class="Constant"> 2</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L373" class="LineNr">373 </span>  <span class="Conceal">¦</span> stash <a href='064list.mu.html#L6'>list</a>
+<span id="L374" class="LineNr">374 </span>  ]
+<span id="L375" class="LineNr">375 </span>  trace-should-contain [
+<span id="L376" class="LineNr">376 </span>  <span class="Conceal">¦</span> app:<span class="Constant"> 5</span>
+<span id="L377" class="LineNr">377 </span>  ]
+<span id="L378" class="LineNr">378 </span>]
+<span id="L379" class="LineNr">379 </span>
+<span id="L380" class="LineNr">380 </span><span class="Comment"># remove values between 'start' and 'end' (both exclusive).</span>
+<span id="L381" class="LineNr">381 </span><span class="Comment"># also clear pointers back out from start/end for hygiene.</span>
+<span id="L382" class="LineNr">382 </span><span class="Comment"># set end to 0 to delete everything past start.</span>
+<span id="L383" class="LineNr">383 </span><span class="Comment"># can't set start to 0 to delete everything before end, because there's no</span>
+<span id="L384" class="LineNr">384 </span><span class="Comment"># clean way to return the new head pointer.</span>
+<span id="L385" class="LineNr">385 </span><span class="muRecipe">def</span> <a href='065duplex_list.mu.html#L385'>remove-between</a> start:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem, end:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:start<span class="muRecipe"> -&gt; </span>start:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
+<span id="L386" class="LineNr">386 </span>  <span class="Constant">local-scope</span>
+<span id="L387" class="LineNr">387 </span>  <span class="Constant">load-ingredients</span>
+<span id="L388" class="LineNr">388 </span>  <a href='065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> get *start, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>
+<span id="L389" class="LineNr">389 </span>  nothing-to-delete?:bool <span class="Special">&lt;-</span> equal <a href='065duplex_list.mu.html#L25'>next</a>, end
+<span id="L390" class="LineNr">390 </span>  <span class="muControl">return-if</span> nothing-to-delete?
+<span id="L391" class="LineNr">391 </span>  assert <a href='065duplex_list.mu.html#L25'>next</a>, <span class="Constant">[malformed duplex list]</span>
+<span id="L392" class="LineNr">392 </span>  <span class="Comment"># start-&gt;next-&gt;prev = 0</span>
+<span id="L393" class="LineNr">393 </span>  <span class="Comment"># start-&gt;next = end</span>
+<span id="L394" class="LineNr">394 </span>  *next <span class="Special">&lt;-</span> put *next, <span class="Constant"><a href='065duplex_list.mu.html#L32'>prev</a>:offset</span>,<span class="Constant"> 0</span>
+<span id="L395" class="LineNr">395 </span>  *start <span class="Special">&lt;-</span> put *start, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>, end
+<span id="L396" class="LineNr">396 </span>  <span class="muControl">return-unless</span> end
+<span id="L397" class="LineNr">397 </span>  <span class="Comment"># end-&gt;prev-&gt;next = 0</span>
+<span id="L398" class="LineNr">398 </span>  <span class="Comment"># end-&gt;prev = start</span>
+<span id="L399" class="LineNr">399 </span>  <a href='065duplex_list.mu.html#L32'>prev</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> get *end, <span class="Constant"><a href='065duplex_list.mu.html#L32'>prev</a>:offset</span>
+<span id="L400" class="LineNr">400 </span>  assert <a href='065duplex_list.mu.html#L32'>prev</a>, <span class="Constant">[malformed duplex <a href='064list.mu.html#L6'>list</a> - 2]</span>
+<span id="L401" class="LineNr">401 </span>  *prev <span class="Special">&lt;-</span> put *prev, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>,<span class="Constant"> 0</span>
+<span id="L402" class="LineNr">402 </span>  *end <span class="Special">&lt;-</span> put *end, <span class="Constant"><a href='065duplex_list.mu.html#L32'>prev</a>:offset</span>, start
+<span id="L403" class="LineNr">403 </span>]
+<span id="L404" class="LineNr">404 </span>
+<span id="L405" class="LineNr">405 </span><span class="muScenario">scenario</span> remove-range [
+<span id="L406" class="LineNr">406 </span>  <span class="Comment"># construct a duplex list with six elements [13, 14, 15, 16, 17, 18]</span>
+<span id="L407" class="LineNr">407 </span>  <span class="Constant">local-scope</span>
+<span id="L408" class="LineNr">408 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 18</span>,<span class="Constant"> 0</span>
+<span id="L409" class="LineNr">409 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 17</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L410" class="LineNr">410 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 16</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L411" class="LineNr">411 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 15</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L412" class="LineNr">412 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 14</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L413" class="LineNr">413 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 13</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L414" class="LineNr">414 </span>  run [
+<span id="L415" class="LineNr">415 </span>  <span class="Conceal">¦</span> <span class="Comment"># delete 16 onwards</span>
+<span id="L416" class="LineNr">416 </span>  <span class="Conceal">¦</span> <span class="Comment"># first pointer: to the third element</span>
+<span id="L417" class="LineNr">417 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L418" class="LineNr">418 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L419" class="LineNr">419 </span>  <span class="Conceal">¦</span> list2 <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L385'>remove-between</a> list2,<span class="Constant"> 0</span>
+<span id="L420" class="LineNr">420 </span>  <span class="Conceal">¦</span> <span class="Comment"># now check the list</span>
+<span id="L421" class="LineNr">421 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
+<span id="L422" class="LineNr">422 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L423" class="LineNr">423 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
+<span id="L424" class="LineNr">424 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L425" class="LineNr">425 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
+<span id="L426" class="LineNr">426 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L427" class="LineNr">427 </span>  ]
+<span id="L428" class="LineNr">428 </span>  memory-should-contain [
+<span id="L429" class="LineNr">429 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 13</span>
+<span id="L430" class="LineNr">430 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 14</span>
+<span id="L431" class="LineNr">431 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 15</span>
+<span id="L432" class="LineNr">432 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L433" class="LineNr">433 </span>  ]
+<span id="L434" class="LineNr">434 </span>]
+<span id="L435" class="LineNr">435 </span>
+<span id="L436" class="LineNr">436 </span><span class="muScenario">scenario</span> remove-range-to-final [
+<span id="L437" class="LineNr">437 </span>  <span class="Constant">local-scope</span>
+<span id="L438" class="LineNr">438 </span>  <span class="Comment"># construct a duplex list with six elements [13, 14, 15, 16, 17, 18]</span>
+<span id="L439" class="LineNr">439 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 18</span>,<span class="Constant"> 0</span>
+<span id="L440" class="LineNr">440 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 17</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L441" class="LineNr">441 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 16</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L442" class="LineNr">442 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 15</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L443" class="LineNr">443 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 14</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L444" class="LineNr">444 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 13</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L445" class="LineNr">445 </span>  run [
+<span id="L446" class="LineNr">446 </span>  <span class="Conceal">¦</span> <span class="Comment"># delete 15, 16 and 17</span>
+<span id="L447" class="LineNr">447 </span>  <span class="Conceal">¦</span> <span class="Comment"># start pointer: to the second element</span>
+<span id="L448" class="LineNr">448 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L449" class="LineNr">449 </span>  <span class="Conceal">¦</span> <span class="Comment"># end pointer: to the last (sixth) element</span>
+<span id="L450" class="LineNr">450 </span>  <span class="Conceal">¦</span> end:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> list2
+<span id="L451" class="LineNr">451 </span>  <span class="Conceal">¦</span> end <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> end
+<span id="L452" class="LineNr">452 </span>  <span class="Conceal">¦</span> end <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> end
+<span id="L453" class="LineNr">453 </span>  <span class="Conceal">¦</span> end <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> end
+<span id="L454" class="LineNr">454 </span>  <span class="Conceal">¦</span> <a href='065duplex_list.mu.html#L385'>remove-between</a> list2, end
+<span id="L455" class="LineNr">455 </span>  <span class="Conceal">¦</span> <span class="Comment"># now check the list</span>
+<span id="L456" class="LineNr">456 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
+<span id="L457" class="LineNr">457 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L458" class="LineNr">458 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
+<span id="L459" class="LineNr">459 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L460" class="LineNr">460 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
+<span id="L461" class="LineNr">461 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L462" class="LineNr">462 </span>  ]
+<span id="L463" class="LineNr">463 </span>  memory-should-contain [
+<span id="L464" class="LineNr">464 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 13</span>
+<span id="L465" class="LineNr">465 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 14</span>
+<span id="L466" class="LineNr">466 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 18</span>
+<span id="L467" class="LineNr">467 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># no more elements</span>
+<span id="L468" class="LineNr">468 </span>  ]
+<span id="L469" class="LineNr">469 </span>]
+<span id="L470" class="LineNr">470 </span>
+<span id="L471" class="LineNr">471 </span><span class="muScenario">scenario</span> remove-range-empty [
+<span id="L472" class="LineNr">472 </span>  <span class="Constant">local-scope</span>
+<span id="L473" class="LineNr">473 </span>  <span class="Comment"># construct a duplex list with three elements [13, 14, 15]</span>
+<span id="L474" class="LineNr">474 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 15</span>,<span class="Constant"> 0</span>
+<span id="L475" class="LineNr">475 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 14</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L476" class="LineNr">476 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 13</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L477" class="LineNr">477 </span>  run [
+<span id="L478" class="LineNr">478 </span>  <span class="Conceal">¦</span> <span class="Comment"># delete between first and second element (i.e. nothing)</span>
+<span id="L479" class="LineNr">479 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L480" class="LineNr">480 </span>  <span class="Conceal">¦</span> <a href='065duplex_list.mu.html#L385'>remove-between</a> <a href='064list.mu.html#L6'>list</a>, list2
+<span id="L481" class="LineNr">481 </span>  <span class="Conceal">¦</span> <span class="Comment"># now check the list</span>
+<span id="L482" class="LineNr">482 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
+<span id="L483" class="LineNr">483 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L484" class="LineNr">484 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
+<span id="L485" class="LineNr">485 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L486" class="LineNr">486 </span>  <span class="Conceal">¦</span> 12:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
+<span id="L487" class="LineNr">487 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L488" class="LineNr">488 </span>  ]
+<span id="L489" class="LineNr">489 </span>  <span class="Comment"># no change</span>
+<span id="L490" class="LineNr">490 </span>  memory-should-contain [
+<span id="L491" class="LineNr">491 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 13</span>
+<span id="L492" class="LineNr">492 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 14</span>
+<span id="L493" class="LineNr">493 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 15</span>
+<span id="L494" class="LineNr">494 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L495" class="LineNr">495 </span>  ]
+<span id="L496" class="LineNr">496 </span>]
+<span id="L497" class="LineNr">497 </span>
+<span id="L498" class="LineNr">498 </span><span class="muScenario">scenario</span> remove-range-to-end [
+<span id="L499" class="LineNr">499 </span>  <span class="Constant">local-scope</span>
+<span id="L500" class="LineNr">500 </span>  <span class="Comment"># construct a duplex list with six elements [13, 14, 15, 16, 17, 18]</span>
+<span id="L501" class="LineNr">501 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 18</span>,<span class="Constant"> 0</span>
+<span id="L502" class="LineNr">502 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 17</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L503" class="LineNr">503 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 16</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L504" class="LineNr">504 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 15</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L505" class="LineNr">505 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 14</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L506" class="LineNr">506 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 13</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L507" class="LineNr">507 </span>  run [
+<span id="L508" class="LineNr">508 </span>  <span class="Conceal">¦</span> <span class="Comment"># remove the third element and beyond</span>
+<span id="L509" class="LineNr">509 </span>  <span class="Conceal">¦</span> list2:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L510" class="LineNr">510 </span>  <span class="Conceal">¦</span> <a href='065duplex_list.mu.html#L385'>remove-between</a> list2,<span class="Constant"> 0</span>
+<span id="L511" class="LineNr">511 </span>  <span class="Conceal">¦</span> <span class="Comment"># now check the list</span>
+<span id="L512" class="LineNr">512 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
+<span id="L513" class="LineNr">513 </span>  <span class="Conceal">¦</span> <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L514" class="LineNr">514 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *list, <span class="Constant">value:offset</span>
+<span id="L515" class="LineNr">515 </span>  <span class="Conceal">¦</span> 20:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> <a href='064list.mu.html#L6'>list</a>
+<span id="L516" class="LineNr">516 </span>  ]
+<span id="L517" class="LineNr">517 </span>  memory-should-contain [
+<span id="L518" class="LineNr">518 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 13</span>
+<span id="L519" class="LineNr">519 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 14</span>
+<span id="L520" class="LineNr">520 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>
+<span id="L521" class="LineNr">521 </span>  ]
+<span id="L522" class="LineNr">522 </span>]
+<span id="L523" class="LineNr">523 </span>
+<span id="L524" class="LineNr">524 </span><span class="Comment"># insert list beginning at 'start' after 'in'</span>
+<span id="L525" class="LineNr">525 </span><span class="muRecipe">def</span> <a href='065duplex_list.mu.html#L525'>splice</a> in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem, start:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:in<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
+<span id="L526" class="LineNr">526 </span>  <span class="Constant">local-scope</span>
+<span id="L527" class="LineNr">527 </span>  <span class="Constant">load-ingredients</span>
+<span id="L528" class="LineNr">528 </span>  <span class="muControl">return-unless</span> in
+<span id="L529" class="LineNr">529 </span>  <span class="muControl">return-unless</span> start
+<span id="L530" class="LineNr">530 </span>  end:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L572'>last</a> start
+<span id="L531" class="LineNr">531 </span>  <a href='065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> in
+<span id="L532" class="LineNr">532 </span>  <span class="Delimiter">{</span>
+<span id="L533" class="LineNr">533 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='065duplex_list.mu.html#L25'>next</a>
+<span id="L534" class="LineNr">534 </span>  <span class="Conceal">¦</span> *end <span class="Special">&lt;-</span> put *end, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>, <a href='065duplex_list.mu.html#L25'>next</a>
+<span id="L535" class="LineNr">535 </span>  <span class="Conceal">¦</span> *next <span class="Special">&lt;-</span> put *next, <span class="Constant"><a href='065duplex_list.mu.html#L32'>prev</a>:offset</span>, end
+<span id="L536" class="LineNr">536 </span>  <span class="Delimiter">}</span>
+<span id="L537" class="LineNr">537 </span>  *in <span class="Special">&lt;-</span> put *in, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>, start
+<span id="L538" class="LineNr">538 </span>  *start <span class="Special">&lt;-</span> put *start, <span class="Constant"><a href='065duplex_list.mu.html#L32'>prev</a>:offset</span>, in
+<span id="L539" class="LineNr">539 </span>]
+<span id="L540" class="LineNr">540 </span>
+<span id="L541" class="LineNr">541 </span><span class="Comment"># insert contents of 'new' after 'in'</span>
+<span id="L542" class="LineNr">542 </span><span class="muRecipe">def</span> insert in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem, new:&amp;:@:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
+<span id="L543" class="LineNr">543 </span>  <span class="Constant">local-scope</span>
+<span id="L544" class="LineNr">544 </span>  <span class="Constant">load-ingredients</span>
+<span id="L545" class="LineNr">545 </span>  <span class="muControl">return-unless</span> in
+<span id="L546" class="LineNr">546 </span>  <span class="muControl">return-unless</span> new
+<span id="L547" class="LineNr">547 </span>  len:num <span class="Special">&lt;-</span> length *new
+<span id="L548" class="LineNr">548 </span>  <span class="muControl">return-unless</span> len
+<span id="L549" class="LineNr">549 </span>  curr:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> copy in
+<span id="L550" class="LineNr">550 </span>  idx:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
+<span id="L551" class="LineNr">551 </span>  <span class="Delimiter">{</span>
+<span id="L552" class="LineNr">552 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal idx, len
+<span id="L553" class="LineNr">553 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L554" class="LineNr">554 </span>  <span class="Conceal">¦</span> c:_elem <span class="Special">&lt;-</span> index *new, idx
+<span id="L555" class="LineNr">555 </span>  <span class="Conceal">¦</span> insert c, curr
+<span id="L556" class="LineNr">556 </span>  <span class="Conceal">¦</span> <span class="Comment"># next iter</span>
+<span id="L557" class="LineNr">557 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> curr
+<span id="L558" class="LineNr">558 </span>  <span class="Conceal">¦</span> idx <span class="Special">&lt;-</span> add idx,<span class="Constant"> 1</span>
+<span id="L559" class="LineNr">559 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L560" class="LineNr">560 </span>  <span class="Delimiter">}</span>
+<span id="L561" class="LineNr">561 </span>]
+<span id="L562" class="LineNr">562 </span>
+<span id="L563" class="LineNr">563 </span><span class="muRecipe">def</span> append in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem, new:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem/contained-in:in<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
+<span id="L564" class="LineNr">564 </span>  <span class="Constant">local-scope</span>
+<span id="L565" class="LineNr">565 </span>  <span class="Constant">load-ingredients</span>
+<span id="L566" class="LineNr">566 </span>  <a href='065duplex_list.mu.html#L572'>last</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L572'>last</a> in
+<span id="L567" class="LineNr">567 </span>  *last <span class="Special">&lt;-</span> put *last, <span class="Constant"><a href='065duplex_list.mu.html#L25'>next</a>:offset</span>, new
+<span id="L568" class="LineNr">568 </span>  <span class="muControl">return-unless</span> new
+<span id="L569" class="LineNr">569 </span>  *new <span class="Special">&lt;-</span> put *new, <span class="Constant"><a href='065duplex_list.mu.html#L32'>prev</a>:offset</span>, <a href='065duplex_list.mu.html#L572'>last</a>
+<span id="L570" class="LineNr">570 </span>]
+<span id="L571" class="LineNr">571 </span>
+<span id="L572" class="LineNr">572 </span><span class="muRecipe">def</span> <a href='065duplex_list.mu.html#L572'>last</a> in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>result:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
+<span id="L573" class="LineNr">573 </span>  <span class="Constant">local-scope</span>
+<span id="L574" class="LineNr">574 </span>  <span class="Constant">load-ingredients</span>
+<span id="L575" class="LineNr">575 </span>  result <span class="Special">&lt;-</span> copy in
+<span id="L576" class="LineNr">576 </span>  <span class="Delimiter">{</span>
+<span id="L577" class="LineNr">577 </span>  <span class="Conceal">¦</span> <a href='065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> result
+<span id="L578" class="LineNr">578 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='065duplex_list.mu.html#L25'>next</a>
+<span id="L579" class="LineNr">579 </span>  <span class="Conceal">¦</span> result <span class="Special">&lt;-</span> copy <a href='065duplex_list.mu.html#L25'>next</a>
+<span id="L580" class="LineNr">580 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L581" class="LineNr">581 </span>  <span class="Delimiter">}</span>
+<span id="L582" class="LineNr">582 </span>]
+<span id="L583" class="LineNr">583 </span>
+<span id="L584" class="LineNr">584 </span><span class="Comment"># does a duplex list start with a certain sequence of elements?</span>
+<span id="L585" class="LineNr">585 </span><span class="muRecipe">def</span> <a href='065duplex_list.mu.html#L585'>match</a> x:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem, y:&amp;:@:_elem<span class="muRecipe"> -&gt; </span>result:bool [
+<span id="L586" class="LineNr">586 </span>  <span class="Constant">local-scope</span>
+<span id="L587" class="LineNr">587 </span>  <span class="Constant">load-ingredients</span>
+<span id="L588" class="LineNr">588 </span>  i:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
+<span id="L589" class="LineNr">589 </span>  max:num <span class="Special">&lt;-</span> length *y
+<span id="L590" class="LineNr">590 </span>  <span class="Delimiter">{</span>
+<span id="L591" class="LineNr">591 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal i, max
+<span id="L592" class="LineNr">592 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
+<span id="L593" class="LineNr">593 </span>  <span class="Conceal">¦</span> expected:_elem <span class="Special">&lt;-</span> index *y, i
+<span id="L594" class="LineNr">594 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> x, <span class="Constant">0/no-match</span>
+<span id="L595" class="LineNr">595 </span>  <span class="Conceal">¦</span> curr:_elem <span class="Special">&lt;-</span> first x
+<span id="L596" class="LineNr">596 </span>  <span class="Conceal">¦</span> curr-matches?:bool <span class="Special">&lt;-</span> equal curr, expected
+<span id="L597" class="LineNr">597 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> curr-matches?, <span class="Constant">0/no-match</span>
+<span id="L598" class="LineNr">598 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> x
+<span id="L599" class="LineNr">599 </span>  <span class="Conceal">¦</span> i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
+<span id="L600" class="LineNr">600 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L601" class="LineNr">601 </span>  <span class="Delimiter">}</span>
+<span id="L602" class="LineNr">602 </span>  <span class="muControl">return</span> <span class="Constant">1/successful-match</span>
+<span id="L603" class="LineNr">603 </span>]
+<span id="L604" class="LineNr">604 </span>
+<span id="L605" class="LineNr">605 </span><span class="muScenario">scenario</span> duplex-list-match [
+<span id="L606" class="LineNr">606 </span>  <span class="Constant">local-scope</span>
+<span id="L607" class="LineNr">607 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> push <span class="Constant">97/a</span>,<span class="Constant"> 0</span>
+<span id="L608" class="LineNr">608 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push <span class="Constant">98/b</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L609" class="LineNr">609 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push <span class="Constant">99/c</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L610" class="LineNr">610 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push <span class="Constant">100/d</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L611" class="LineNr">611 </span>  run [
+<span id="L612" class="LineNr">612 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L585'>match</a> <a href='064list.mu.html#L6'>list</a>, <span class="Constant">[]</span>
+<span id="L613" class="LineNr">613 </span>  <span class="Conceal">¦</span> 11:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L585'>match</a> <a href='064list.mu.html#L6'>list</a>, <span class="Constant">[d]</span>
+<span id="L614" class="LineNr">614 </span>  <span class="Conceal">¦</span> 12:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L585'>match</a> <a href='064list.mu.html#L6'>list</a>, <span class="Constant">[dc]</span>
+<span id="L615" class="LineNr">615 </span>  <span class="Conceal">¦</span> 13:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L585'>match</a> <a href='064list.mu.html#L6'>list</a>, <span class="Constant">[dcba]</span>
+<span id="L616" class="LineNr">616 </span>  <span class="Conceal">¦</span> 14:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L585'>match</a> <a href='064list.mu.html#L6'>list</a>, <span class="Constant">[dd]</span>
+<span id="L617" class="LineNr">617 </span>  <span class="Conceal">¦</span> 15:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L585'>match</a> <a href='064list.mu.html#L6'>list</a>, <span class="Constant">[dcbax]</span>
+<span id="L618" class="LineNr">618 </span>  ]
+<span id="L619" class="LineNr">619 </span>  memory-should-contain [
+<span id="L620" class="LineNr">620 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># matches []</span>
+<span id="L621" class="LineNr">621 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># matches [d]</span>
+<span id="L622" class="LineNr">622 </span>  <span class="Conceal">¦</span><span class="Constant"> 12</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># matches [dc]</span>
+<span id="L623" class="LineNr">623 </span>  <span class="Conceal">¦</span><span class="Constant"> 13</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># matches [dcba]</span>
+<span id="L624" class="LineNr">624 </span>  <span class="Conceal">¦</span><span class="Constant"> 14</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># does not match [dd]</span>
+<span id="L625" class="LineNr">625 </span>  <span class="Conceal">¦</span><span class="Constant"> 15</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># does not match [dcbax]</span>
+<span id="L626" class="LineNr">626 </span>  ]
+<span id="L627" class="LineNr">627 </span>]
+<span id="L628" class="LineNr">628 </span>
+<span id="L629" class="LineNr">629 </span><span class="Comment"># helper for debugging</span>
+<span id="L630" class="LineNr">630 </span><span class="muRecipe">def</span> <a href='065duplex_list.mu.html#L630'>dump-from</a> x:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem [
+<span id="L631" class="LineNr">631 </span>  <span class="Constant">local-scope</span>
+<span id="L632" class="LineNr">632 </span>  <span class="Constant">load-ingredients</span>
+<span id="L633" class="LineNr">633 </span>  $print x, <span class="Constant">[: ]</span>
+<span id="L634" class="LineNr">634 </span>  <span class="Delimiter">{</span>
+<span id="L635" class="LineNr">635 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> x
+<span id="L636" class="LineNr">636 </span>  <span class="Conceal">¦</span> c:_elem <span class="Special">&lt;-</span> get *x, <span class="Constant">value:offset</span>
+<span id="L637" class="LineNr">637 </span>  <span class="Conceal">¦</span> $print c, <span class="Constant">[ ]</span>
+<span id="L638" class="LineNr">638 </span>  <span class="Conceal">¦</span> x <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> x
+<span id="L639" class="LineNr">639 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
+<span id="L640" class="LineNr">640 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> is-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
+<span id="L641" class="LineNr">641 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> is-newline?
+<span id="L642" class="LineNr">642 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> $print <span class="Constant">10/newline</span>
+<span id="L643" class="LineNr">643 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> $print x, <span class="Constant">[: ]</span>
+<span id="L644" class="LineNr">644 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L645" class="LineNr">645 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L646" class="LineNr">646 </span>  <span class="Delimiter">}</span>
+<span id="L647" class="LineNr">647 </span>  $print <span class="Constant">10/newline</span>, <span class="Constant">[---]</span>, <span class="Constant">10/newline</span>
+<span id="L648" class="LineNr">648 </span>]
+<span id="L649" class="LineNr">649 </span>
+<span id="L650" class="LineNr">650 </span><span class="muScenario">scenario</span> stash-duplex-list [
+<span id="L651" class="LineNr">651 </span>  <span class="Constant">local-scope</span>
+<span id="L652" class="LineNr">652 </span>  <a href='064list.mu.html#L6'>list</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> push<span class="Constant"> 1</span>,<span class="Constant"> 0</span>
+<span id="L653" class="LineNr">653 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 2</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L654" class="LineNr">654 </span>  <a href='064list.mu.html#L6'>list</a> <span class="Special">&lt;-</span> push<span class="Constant"> 3</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L655" class="LineNr">655 </span>  run [
+<span id="L656" class="LineNr">656 </span>  <span class="Conceal">¦</span> stash <span class="Constant">[list:]</span>, <a href='064list.mu.html#L6'>list</a>
+<span id="L657" class="LineNr">657 </span>  ]
+<span id="L658" class="LineNr">658 </span>  trace-should-contain [
+<span id="L659" class="LineNr">659 </span>  <span class="Conceal">¦</span> app: <a href='064list.mu.html#L6'>list</a>:<span class="Constant"> 3</span> <span class="Special">&lt;-</span>&gt;<span class="Constant"> 2</span> <span class="Special">&lt;-</span>&gt;<span class="Constant"> 1</span>
+<span id="L660" class="LineNr">660 </span>  ]
+<span id="L661" class="LineNr">661 </span>]
+<span id="L662" class="LineNr">662 </span>
+<span id="L663" class="LineNr">663 </span><span class="muRecipe">def</span> to-text in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>result:text [
+<span id="L664" class="LineNr">664 </span>  <span class="Constant">local-scope</span>
+<span id="L665" class="LineNr">665 </span>  <span class="Constant">load-ingredients</span>
+<span id="L666" class="LineNr">666 </span>  buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char <span class="Special">&lt;-</span> <a href='061text.mu.html#L125'>new-buffer</a><span class="Constant"> 80</span>
+<span id="L667" class="LineNr">667 </span>  buf <span class="Special">&lt;-</span> to-buffer in, buf
+<span id="L668" class="LineNr">668 </span>  result <span class="Special">&lt;-</span> <a href='061text.mu.html#L338'>buffer-to-array</a> buf
+<span id="L669" class="LineNr">669 </span>]
+<span id="L670" class="LineNr">670 </span>
+<span id="L671" class="LineNr">671 </span><span class="Comment"># variant of 'to-text' which stops printing after a few elements (and so is robust to cycles)</span>
+<span id="L672" class="LineNr">672 </span><span class="muRecipe">def</span> to-text-line in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem<span class="muRecipe"> -&gt; </span>result:text [
+<span id="L673" class="LineNr">673 </span>  <span class="Constant">local-scope</span>
+<span id="L674" class="LineNr">674 </span>  <span class="Constant">load-ingredients</span>
+<span id="L675" class="LineNr">675 </span>  buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char <span class="Special">&lt;-</span> <a href='061text.mu.html#L125'>new-buffer</a><span class="Constant"> 80</span>
+<span id="L676" class="LineNr">676 </span>  buf <span class="Special">&lt;-</span> to-buffer in, buf,<span class="Constant"> 6</span>  <span class="Comment"># max elements to display</span>
+<span id="L677" class="LineNr">677 </span>  result <span class="Special">&lt;-</span> <a href='061text.mu.html#L338'>buffer-to-array</a> buf
+<span id="L678" class="LineNr">678 </span>]
+<span id="L679" class="LineNr">679 </span>
+<span id="L680" class="LineNr">680 </span><span class="muRecipe">def</span> to-buffer in:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem, buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char<span class="muRecipe"> -&gt; </span>buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char [
+<span id="L681" class="LineNr">681 </span>  <span class="Constant">local-scope</span>
+<span id="L682" class="LineNr">682 </span>  <span class="Constant">load-ingredients</span>
+<span id="L683" class="LineNr">683 </span>  <span class="Delimiter">{</span>
+<span id="L684" class="LineNr">684 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> in
+<span id="L685" class="LineNr">685 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> append buf, <span class="Constant">[[]</span>]
+<span id="L686" class="LineNr">686 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
+<span id="L687" class="LineNr">687 </span>  <span class="Delimiter">}</span>
+<span id="L688" class="LineNr">688 </span>  <span class="Comment"># append in.value to buf</span>
+<span id="L689" class="LineNr">689 </span>  val:_elem <span class="Special">&lt;-</span> get *in, <span class="Constant">value:offset</span>
+<span id="L690" class="LineNr">690 </span>  buf <span class="Special">&lt;-</span> append buf, val
+<span id="L691" class="LineNr">691 </span>  <span class="Comment"># now prepare next</span>
+<span id="L692" class="LineNr">692 </span>  <a href='065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:_elem <span class="Special">&lt;-</span> <a href='065duplex_list.mu.html#L25'>next</a> in
+<span id="L693" class="LineNr">693 </span>  nextn:num <span class="Special">&lt;-</span> copy <a href='065duplex_list.mu.html#L25'>next</a>
+<span id="L694" class="LineNr">694 </span>  <span class="muControl">return-unless</span> <a href='065duplex_list.mu.html#L25'>next</a>
+<span id="L695" class="LineNr">695 </span>  buf <span class="Special">&lt;-</span> append buf, <span class="Constant">[ &lt;-&gt; ]</span>
+<span id="L696" class="LineNr">696 </span>  <span class="Comment"># and recurse</span>
+<span id="L697" class="LineNr">697 </span>  remaining:num, optional-ingredient-found?:bool <span class="Special">&lt;-</span> <span class="Constant">next-ingredient</span>
+<span id="L698" class="LineNr">698 </span>  <span class="Delimiter">{</span>
+<span id="L699" class="LineNr">699 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> optional-ingredient-found?
+<span id="L700" class="LineNr">700 </span>  <span class="Conceal">¦</span> <span class="Comment"># unlimited recursion</span>
+<span id="L701" class="LineNr">701 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> to-buffer <a href='065duplex_list.mu.html#L25'>next</a>, buf
+<span id="L702" class="LineNr">702 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
+<span id="L703" class="LineNr">703 </span>  <span class="Delimiter">}</span>
+<span id="L704" class="LineNr">704 </span>  <span class="Delimiter">{</span>
+<span id="L705" class="LineNr">705 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> remaining
+<span id="L706" class="LineNr">706 </span>  <span class="Conceal">¦</span> <span class="Comment"># limited recursion</span>
+<span id="L707" class="LineNr">707 </span>  <span class="Conceal">¦</span> remaining <span class="Special">&lt;-</span> subtract remaining,<span class="Constant"> 1</span>
+<span id="L708" class="LineNr">708 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> to-buffer <a href='065duplex_list.mu.html#L25'>next</a>, buf, remaining
+<span id="L709" class="LineNr">709 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span>
+<span id="L710" class="LineNr">710 </span>  <span class="Delimiter">}</span>
+<span id="L711" class="LineNr">711 </span>  <span class="Comment"># past recursion depth; insert ellipses and stop</span>
+<span id="L712" class="LineNr">712 </span>  append buf, <span class="Constant">[...]</span>
+<span id="L713" class="LineNr">713 </span>]
+<span id="L714" class="LineNr">714 </span>
+<span id="L715" class="LineNr">715 </span><span class="muScenario">scenario</span> stash-empty-duplex-list [
+<span id="L716" class="LineNr">716 </span>  <span class="Constant">local-scope</span>
+<span id="L717" class="LineNr">717 </span>  x:&amp;:<a href='065duplex_list.mu.html#L3'>duplex-list</a>:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
+<span id="L718" class="LineNr">718 </span>  run [
+<span id="L719" class="LineNr">719 </span>  <span class="Conceal">¦</span> stash x
+<span id="L720" class="LineNr">720 </span>  ]
+<span id="L721" class="LineNr">721 </span>  trace-should-contain [
+<span id="L722" class="LineNr">722 </span>  <span class="Conceal">¦</span> app: <span class="Constant">[]</span>
+<span id="L723" class="LineNr">723 </span>  ]
+<span id="L724" class="LineNr">724 </span>]
 </pre>
 </body>
 </html>
diff --git a/html/edit/001-editor.mu.html b/html/edit/001-editor.mu.html
index 8b13fc80..215debfd 100644
--- a/html/edit/001-editor.mu.html
+++ b/html/edit/001-editor.mu.html
@@ -177,8 +177,8 @@ if ('onhashchange' in window) {
 <span id="L113" class="LineNr">113 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
 <span id="L114" class="LineNr">114 </span>  <span class="Comment"># traversing editor</span>
 <span id="L115" class="LineNr">115 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L116" class="LineNr">116 </span>  <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy curr  <span class="Comment"># just in case curr becomes null and we can't compute prev</span>
-<span id="L117" class="LineNr">117 </span>  curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L116" class="LineNr">116 </span>  <a href='../065duplex_list.mu.html#L32'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy curr  <span class="Comment"># just in case curr becomes null and we can't compute prev</span>
+<span id="L117" class="LineNr">117 </span>  curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
 <span id="L118" class="LineNr">118 </span>  <span class="Comment"># traversing screen</span>
 <span id="L119" class="LineNr">119 </span>  color:num <span class="Special">&lt;-</span> copy <span class="Constant">7/white</span>
 <span id="L120" class="LineNr">120 </span>  row:num <span class="Special">&lt;-</span> copy <span class="Constant">1/top</span>
@@ -200,7 +200,7 @@ if ('onhashchange' in window) {
 <span id="L136" class="LineNr">136 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-cursor-row?
 <span id="L137" class="LineNr">137 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-cursor?:bool <span class="Special">&lt;-</span> equal column, cursor-column
 <span id="L138" class="LineNr">138 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-cursor?
-<span id="L139" class="LineNr">139 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L139" class="LineNr">139 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L140" class="LineNr">140 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L141" class="LineNr">141 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
 <span id="L142" class="LineNr">142 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;character-c-received&gt;</span>
@@ -215,7 +215,7 @@ if ('onhashchange' in window) {
 <span id="L151" class="LineNr">151 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> left-of-cursor?:bool <span class="Special">&lt;-</span> lesser-than column, cursor-column
 <span id="L152" class="LineNr">152 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> left-of-cursor?
 <span id="L153" class="LineNr">153 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy column
-<span id="L154" class="LineNr">154 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
+<span id="L154" class="LineNr">154 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> curr
 <span id="L155" class="LineNr">155 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L156" class="LineNr">156 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># clear rest of line in this window</span>
 <span id="L157" class="LineNr">157 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L553'>clear-line-until</a> <a href='../081print.mu.html#L16'>screen</a>, right
@@ -223,8 +223,8 @@ if ('onhashchange' in window) {
 <span id="L159" class="LineNr">159 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
 <span id="L160" class="LineNr">160 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> copy left
 <span id="L161" class="LineNr">161 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, row, column
-<span id="L162" class="LineNr">162 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L163" class="LineNr">163 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L162" class="LineNr">162 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
+<span id="L163" class="LineNr">163 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L32'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L164" class="LineNr">164 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
 <span id="L165" class="LineNr">165 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L166" class="LineNr">166 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
@@ -242,8 +242,8 @@ if ('onhashchange' in window) {
 <span id="L178" class="LineNr">178 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
 <span id="L179" class="LineNr">179 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L180" class="LineNr">180 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L16'>screen</a>, c, color
-<span id="L181" class="LineNr">181 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L182" class="LineNr">182 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L181" class="LineNr">181 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
+<span id="L182" class="LineNr">182 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L32'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L183" class="LineNr">183 </span>  <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
 <span id="L184" class="LineNr">184 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L185" class="LineNr">185 </span>  <span class="Delimiter">}</span>
@@ -259,7 +259,7 @@ if ('onhashchange' in window) {
 <span id="L195" class="LineNr">195 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> before-cursor?
 <span id="L196" class="LineNr">196 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> copy row
 <span id="L197" class="LineNr">197 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy column
-<span id="L198" class="LineNr">198 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L198" class="LineNr">198 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L199" class="LineNr">199 </span>  <span class="Delimiter">}</span>
 <span id="L200" class="LineNr">200 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">bottom:offset</span>, row
 <span id="L201" class="LineNr">201 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
diff --git a/html/edit/002-typing.mu.html b/html/edit/002-typing.mu.html
index 20ceb7c8..eb828377 100644
--- a/html/edit/002-typing.mu.html
+++ b/html/edit/002-typing.mu.html
@@ -144,8 +144,8 @@ if ('onhashchange' in window) {
 <span id="L81" class="LineNr">  81 </span>  <a href='../081print.mu.html#L782'>screen-height</a>:num <span class="Special">&lt;-</span> <a href='../081print.mu.html#L782'>screen-height</a> <a href='../081print.mu.html#L16'>screen</a>
 <span id="L82" class="LineNr">  82 </span>  <span class="Comment"># count newlines until screen row</span>
 <span id="L83" class="LineNr">  83 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L84" class="LineNr">  84 </span>  <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy curr  <span class="Comment"># just in case curr becomes null and we can't compute prev</span>
-<span id="L85" class="LineNr">  85 </span>  curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L84" class="LineNr">  84 </span>  <a href='../065duplex_list.mu.html#L32'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy curr  <span class="Comment"># just in case curr becomes null and we can't compute prev</span>
+<span id="L85" class="LineNr">  85 </span>  curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
 <span id="L86" class="LineNr">  86 </span>  row:num <span class="Special">&lt;-</span> copy <span class="Constant">1/top</span>
 <span id="L87" class="LineNr">  87 </span>  column:num <span class="Special">&lt;-</span> copy left
 <span id="L88" class="LineNr">  88 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, target-row
@@ -166,7 +166,7 @@ if ('onhashchange' in window) {
 <span id="L103" class="LineNr"> 103 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-cursor-row?
 <span id="L104" class="LineNr"> 104 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-cursor?:bool <span class="Special">&lt;-</span> equal column, cursor-column
 <span id="L105" class="LineNr"> 105 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-cursor?
-<span id="L106" class="LineNr"> 106 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L106" class="LineNr"> 106 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L107" class="LineNr"> 107 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L108" class="LineNr"> 108 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L109" class="LineNr"> 109 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
@@ -182,14 +182,14 @@ if ('onhashchange' in window) {
 <span id="L119" class="LineNr"> 119 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> left-of-cursor?
 <span id="L120" class="LineNr"> 120 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy column
 <span id="L121" class="LineNr"> 121 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L122" class="LineNr"> 122 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L122" class="LineNr"> 122 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L123" class="LineNr"> 123 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L124" class="LineNr"> 124 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L125" class="LineNr"> 125 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># skip to next line</span>
 <span id="L126" class="LineNr"> 126 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
 <span id="L127" class="LineNr"> 127 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> copy left
-<span id="L128" class="LineNr"> 128 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L129" class="LineNr"> 129 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L128" class="LineNr"> 128 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
+<span id="L129" class="LineNr"> 129 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L32'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L130" class="LineNr"> 130 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
 <span id="L131" class="LineNr"> 131 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L132" class="LineNr"> 132 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
@@ -202,8 +202,8 @@ if ('onhashchange' in window) {
 <span id="L139" class="LineNr"> 139 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># don't increment curr/prev</span>
 <span id="L140" class="LineNr"> 140 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
 <span id="L141" class="LineNr"> 141 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
-<span id="L142" class="LineNr"> 142 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L143" class="LineNr"> 143 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L142" class="LineNr"> 142 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
+<span id="L143" class="LineNr"> 143 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L32'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L144" class="LineNr"> 144 </span>  <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
 <span id="L145" class="LineNr"> 145 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L146" class="LineNr"> 146 </span>  <span class="Delimiter">}</span>
@@ -219,7 +219,7 @@ if ('onhashchange' in window) {
 <span id="L156" class="LineNr"> 156 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
 <span id="L157" class="LineNr"> 157 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy column
 <span id="L158" class="LineNr"> 158 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L159" class="LineNr"> 159 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L159" class="LineNr"> 159 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L160" class="LineNr"> 160 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L161" class="LineNr"> 161 </span>  <span class="Delimiter">}</span>
 <span id="L162" class="LineNr"> 162 </span>]
@@ -268,7 +268,7 @@ if ('onhashchange' in window) {
 <span id="L205" class="LineNr"> 205 </span>  <span class="Constant">load-ingredients</span>
 <span id="L206" class="LineNr"> 206 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
 <span id="L207" class="LineNr"> 207 </span>  insert c, before-cursor
-<span id="L208" class="LineNr"> 208 </span>  before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L208" class="LineNr"> 208 </span>  before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L209" class="LineNr"> 209 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L210" class="LineNr"> 210 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
 <span id="L211" class="LineNr"> 211 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
@@ -283,10 +283,10 @@ if ('onhashchange' in window) {
 <span id="L220" class="LineNr"> 220 </span>  <span class="Comment"># but mostly we'll just move the cursor right</span>
 <span id="L221" class="LineNr"> 221 </span>  cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
 <span id="L222" class="LineNr"> 222 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L223" class="LineNr"> 223 </span>  <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L223" class="LineNr"> 223 </span>  <a href='../065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L224" class="LineNr"> 224 </span>  <span class="Delimiter">{</span>
 <span id="L225" class="LineNr"> 225 </span>  <span class="Conceal">¦</span> <span class="Comment"># at end of all text? no need to scroll? just print the character and leave</span>
-<span id="L226" class="LineNr"> 226 </span>  <span class="Conceal">¦</span> at-end?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L29'>next</a>, <span class="Constant">0/null</span>
+<span id="L226" class="LineNr"> 226 </span>  <span class="Conceal">¦</span> at-end?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L25'>next</a>, <span class="Constant">0/null</span>
 <span id="L227" class="LineNr"> 227 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-end?
 <span id="L228" class="LineNr"> 228 </span>  <span class="Conceal">¦</span> bottom:num <span class="Special">&lt;-</span> subtract <a href='../081print.mu.html#L782'>screen-height</a>,<span class="Constant"> 1</span>
 <span id="L229" class="LineNr"> 229 </span>  <span class="Conceal">¦</span> at-bottom?:bool <span class="Special">&lt;-</span> equal save-row, bottom
@@ -299,7 +299,7 @@ if ('onhashchange' in window) {
 <span id="L236" class="LineNr"> 236 </span>  <span class="Delimiter">}</span>
 <span id="L237" class="LineNr"> 237 </span>  <span class="Delimiter">{</span>
 <span id="L238" class="LineNr"> 238 </span>  <span class="Conceal">¦</span> <span class="Comment"># not at right margin? print the character and rest of line</span>
-<span id="L239" class="LineNr"> 239 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L239" class="LineNr"> 239 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L25'>next</a>
 <span id="L240" class="LineNr"> 240 </span>  <span class="Conceal">¦</span> at-right?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, <a href='../081print.mu.html#L768'>screen-width</a>
 <span id="L241" class="LineNr"> 241 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-right?
 <span id="L242" class="LineNr"> 242 </span>  <span class="Conceal">¦</span> curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy before-cursor
@@ -316,7 +316,7 @@ if ('onhashchange' in window) {
 <span id="L253" class="LineNr"> 253 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
 <span id="L254" class="LineNr"> 254 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> print <a href='../081print.mu.html#L16'>screen</a>, currc
 <span id="L255" class="LineNr"> 255 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr-column <span class="Special">&lt;-</span> add curr-column,<span class="Constant"> 1</span>
-<span id="L256" class="LineNr"> 256 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L256" class="LineNr"> 256 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
 <span id="L257" class="LineNr"> 257 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L258" class="LineNr"> 258 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L259" class="LineNr"> 259 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
@@ -764,9 +764,9 @@ if ('onhashchange' in window) {
 <span id="L701" class="LineNr"> 701 </span>  <span class="Conceal">¦</span> before-wrap-column:num <span class="Special">&lt;-</span> subtract wrap-column,<span class="Constant"> 1</span>
 <span id="L702" class="LineNr"> 702 </span>  <span class="Conceal">¦</span> at-wrap?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, wrap-column
 <span id="L703" class="LineNr"> 703 </span>  <span class="Conceal">¦</span> just-before-wrap?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, before-wrap-column
-<span id="L704" class="LineNr"> 704 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L704" class="LineNr"> 704 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L705" class="LineNr"> 705 </span>  <span class="Conceal">¦</span> <span class="Comment"># at end of line? next == 0 || next.value == 10/newline</span>
-<span id="L706" class="LineNr"> 706 </span>  <span class="Conceal">¦</span> at-end-of-line?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L29'>next</a>,<span class="Constant"> 0</span>
+<span id="L706" class="LineNr"> 706 </span>  <span class="Conceal">¦</span> at-end-of-line?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L25'>next</a>,<span class="Constant"> 0</span>
 <span id="L707" class="LineNr"> 707 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
 <span id="L708" class="LineNr"> 708 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-end-of-line?
 <span id="L709" class="LineNr"> 709 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> next-character:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
@@ -956,13 +956,13 @@ if ('onhashchange' in window) {
 <span id="L893" class="LineNr"> 893 </span>  <span class="Delimiter">}</span>
 <span id="L894" class="LineNr"> 894 </span>  <span class="Comment"># insert newline</span>
 <span id="L895" class="LineNr"> 895 </span>  insert <span class="Constant">10/newline</span>, before-cursor
-<span id="L896" class="LineNr"> 896 </span>  before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L896" class="LineNr"> 896 </span>  before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L897" class="LineNr"> 897 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L898" class="LineNr"> 898 </span>  <span class="Comment"># indent if necessary</span>
 <span id="L899" class="LineNr"> 899 </span>  indent?:bool <span class="Special">&lt;-</span> get *editor, <span class="Constant">indent?:offset</span>
 <span id="L900" class="LineNr"> 900 </span>  <span class="muControl">return-unless</span> indent?
 <span id="L901" class="LineNr"> 901 </span>  d:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
-<span id="L902" class="LineNr"> 902 </span>  end-of-previous-line:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> before-cursor
+<span id="L902" class="LineNr"> 902 </span>  end-of-previous-line:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> before-cursor
 <span id="L903" class="LineNr"> 903 </span>  indent:num <span class="Special">&lt;-</span> <a href='002-typing.mu.html#L934'>line-indent</a> end-of-previous-line, d
 <span id="L904" class="LineNr"> 904 </span>  i:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
 <span id="L905" class="LineNr"> 905 </span>  <span class="Delimiter">{</span>
@@ -982,7 +982,7 @@ if ('onhashchange' in window) {
 <span id="L919" class="LineNr"> 919 </span>  cursor-at-left?:bool <span class="Special">&lt;-</span> equal cursor-column, left
 <span id="L920" class="LineNr"> 920 </span>  <span class="muControl">return-unless</span> cursor-at-left?, <span class="Constant">0/false</span>
 <span id="L921" class="LineNr"> 921 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
-<span id="L922" class="LineNr"> 922 </span>  before-before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> before-cursor
+<span id="L922" class="LineNr"> 922 </span>  before-before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> before-cursor
 <span id="L923" class="LineNr"> 923 </span>  <span class="muControl">return-unless</span> before-before-cursor, <span class="Constant">0/false</span>  <span class="Comment"># cursor is at start of editor</span>
 <span id="L924" class="LineNr"> 924 </span>  char-before-cursor:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
 <span id="L925" class="LineNr"> 925 </span>  cursor-after-newline?:bool <span class="Special">&lt;-</span> equal char-before-cursor, <span class="Constant">10/newline</span>
@@ -1002,7 +1002,7 @@ if ('onhashchange' in window) {
 <span id="L939" class="LineNr"> 939 </span>  at-start?:bool <span class="Special">&lt;-</span> equal curr, start
 <span id="L940" class="LineNr"> 940 </span>  <span class="muControl">return-if</span> at-start?
 <span id="L941" class="LineNr"> 941 </span>  <span class="Delimiter">{</span>
-<span id="L942" class="LineNr"> 942 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
+<span id="L942" class="LineNr"> 942 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> curr
 <span id="L943" class="LineNr"> 943 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
 <span id="L944" class="LineNr"> 944 </span>  <span class="Conceal">¦</span> at-start?:bool <span class="Special">&lt;-</span> equal curr, start
 <span id="L945" class="LineNr"> 945 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-start?
diff --git a/html/edit/003-shortcuts.mu.html b/html/edit/003-shortcuts.mu.html
index 1cb4f6a3..4d24c08d 100644
--- a/html/edit/003-shortcuts.mu.html
+++ b/html/edit/003-shortcuts.mu.html
@@ -174,14 +174,14 @@ if ('onhashchange' in window) {
 <span id="L112" class="LineNr"> 112 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
 <span id="L113" class="LineNr"> 113 </span>  data:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
 <span id="L114" class="LineNr"> 114 </span>  <span class="Comment"># if at start of text (before-cursor at § sentinel), return</span>
-<span id="L115" class="LineNr"> 115 </span>  <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> before-cursor
-<span id="L116" class="LineNr"> 116 </span>  <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L36'>prev</a>, <span class="Constant">0/no-more-render</span>, <span class="Constant">0/nothing-deleted</span>
+<span id="L115" class="LineNr"> 115 </span>  <a href='../065duplex_list.mu.html#L32'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> before-cursor
+<span id="L116" class="LineNr"> 116 </span>  <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L32'>prev</a>, <span class="Constant">0/no-more-render</span>, <span class="Constant">0/nothing-deleted</span>
 <span id="L117" class="LineNr"> 117 </span>  trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[delete-before-cursor]</span>
 <span id="L118" class="LineNr"> 118 </span>  original-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
 <span id="L119" class="LineNr"> 119 </span>  scroll?:bool <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L156'>move-cursor-coordinates-left</a> editor
 <span id="L120" class="LineNr"> 120 </span>  backspaced-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy before-cursor
 <span id="L121" class="LineNr"> 121 </span>  data <span class="Special">&lt;-</span> remove before-cursor, data  <span class="Comment"># will also neatly trim next/prev pointers in backspaced-cell/before-cursor</span>
-<span id="L122" class="LineNr"> 122 </span>  before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L122" class="LineNr"> 122 </span>  before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L123" class="LineNr"> 123 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L124" class="LineNr"> 124 </span>  <span class="muControl">return-if</span> scroll?, <span class="Constant">1/go-render</span>
 <span id="L125" class="LineNr"> 125 </span>  <a href='../081print.mu.html#L768'>screen-width</a>:num <span class="Special">&lt;-</span> <a href='../081print.mu.html#L768'>screen-width</a> <a href='../081print.mu.html#L16'>screen</a>
@@ -192,7 +192,7 @@ if ('onhashchange' in window) {
 <span id="L130" class="LineNr"> 130 </span>  <span class="muControl">return-unless</span> same-row?, <span class="Constant">1/go-render</span>
 <span id="L131" class="LineNr"> 131 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
 <span id="L132" class="LineNr"> 132 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
-<span id="L133" class="LineNr"> 133 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L133" class="LineNr"> 133 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L134" class="LineNr"> 134 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, cursor-row, cursor-column
 <span id="L135" class="LineNr"> 135 </span>  curr-column:num <span class="Special">&lt;-</span> copy cursor-column
 <span id="L136" class="LineNr"> 136 </span>  <span class="Delimiter">{</span>
@@ -206,7 +206,7 @@ if ('onhashchange' in window) {
 <span id="L144" class="LineNr"> 144 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
 <span id="L145" class="LineNr"> 145 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L16'>screen</a>, currc
 <span id="L146" class="LineNr"> 146 </span>  <span class="Conceal">¦</span> curr-column <span class="Special">&lt;-</span> add curr-column,<span class="Constant"> 1</span>
-<span id="L147" class="LineNr"> 147 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L147" class="LineNr"> 147 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
 <span id="L148" class="LineNr"> 148 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L149" class="LineNr"> 149 </span>  <span class="Delimiter">}</span>
 <span id="L150" class="LineNr"> 150 </span>  <span class="Comment"># we're guaranteed not to be at the right margin</span>
@@ -286,7 +286,7 @@ if ('onhashchange' in window) {
 <span id="L224" class="LineNr"> 224 </span>  at-start?:bool <span class="Special">&lt;-</span> equal curr, start
 <span id="L225" class="LineNr"> 225 </span>  <span class="muControl">return-if</span> at-start?
 <span id="L226" class="LineNr"> 226 </span>  <span class="Delimiter">{</span>
-<span id="L227" class="LineNr"> 227 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
+<span id="L227" class="LineNr"> 227 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> curr
 <span id="L228" class="LineNr"> 228 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
 <span id="L229" class="LineNr"> 229 </span>  <span class="Conceal">¦</span> at-start?:bool <span class="Special">&lt;-</span> equal curr, start
 <span id="L230" class="LineNr"> 230 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-start?
@@ -437,14 +437,14 @@ if ('onhashchange' in window) {
 <span id="L375" class="LineNr"> 375 </span>  <span class="Constant">load-ingredients</span>
 <span id="L376" class="LineNr"> 376 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
 <span id="L377" class="LineNr"> 377 </span>  data:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
-<span id="L378" class="LineNr"> 378 </span>  deleted-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L378" class="LineNr"> 378 </span>  deleted-cell:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L379" class="LineNr"> 379 </span>  <span class="muControl">return-unless</span> deleted-cell, <span class="Constant">0/don't-render</span>
 <span id="L380" class="LineNr"> 380 </span>  currc:char <span class="Special">&lt;-</span> get *deleted-cell, <span class="Constant">value:offset</span>
 <span id="L381" class="LineNr"> 381 </span>  data <span class="Special">&lt;-</span> remove deleted-cell, data
 <span id="L382" class="LineNr"> 382 </span>  deleted-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
 <span id="L383" class="LineNr"> 383 </span>  <span class="muControl">return-if</span> deleted-newline?, <span class="Constant">1/go-render</span>
 <span id="L384" class="LineNr"> 384 </span>  <span class="Comment"># wasn't a newline? render rest of line</span>
-<span id="L385" class="LineNr"> 385 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor  <span class="Comment"># refresh after remove above</span>
+<span id="L385" class="LineNr"> 385 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor  <span class="Comment"># refresh after remove above</span>
 <span id="L386" class="LineNr"> 386 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
 <span id="L387" class="LineNr"> 387 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
 <span id="L388" class="LineNr"> 388 </span>  <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, cursor-row, cursor-column
@@ -460,7 +460,7 @@ if ('onhashchange' in window) {
 <span id="L398" class="LineNr"> 398 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
 <span id="L399" class="LineNr"> 399 </span>  <span class="Conceal">¦</span> <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> print <a href='../081print.mu.html#L16'>screen</a>, currc
 <span id="L400" class="LineNr"> 400 </span>  <span class="Conceal">¦</span> curr-column <span class="Special">&lt;-</span> add curr-column,<span class="Constant"> 1</span>
-<span id="L401" class="LineNr"> 401 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L401" class="LineNr"> 401 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
 <span id="L402" class="LineNr"> 402 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L403" class="LineNr"> 403 </span>  <span class="Delimiter">}</span>
 <span id="L404" class="LineNr"> 404 </span>  <span class="Comment"># we're guaranteed not to be at the right margin</span>
@@ -498,7 +498,7 @@ if ('onhashchange' in window) {
 <span id="L436" class="LineNr"> 436 </span>  <span class="Conceal">¦</span> move-to-next-character?:bool <span class="Special">&lt;-</span> equal k, <span class="Constant">65514/right-arrow</span>
 <span id="L437" class="LineNr"> 437 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> move-to-next-character?
 <span id="L438" class="LineNr"> 438 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not at end of text</span>
-<span id="L439" class="LineNr"> 439 </span>  <span class="Conceal">¦</span> next-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L439" class="LineNr"> 439 </span>  <span class="Conceal">¦</span> next-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L440" class="LineNr"> 440 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> next-cursor
 <span id="L441" class="LineNr"> 441 </span>  <span class="Conceal">¦</span> <span class="Comment"># scan to next character</span>
 <span id="L442" class="LineNr"> 442 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;begin-move-cursor&gt;</span>
@@ -543,8 +543,8 @@ if ('onhashchange' in window) {
 <span id="L481" class="LineNr"> 481 </span>  <span class="Conceal">¦</span> at-wrap?:bool <span class="Special">&lt;-</span> equal cursor-column, wrap-column
 <span id="L482" class="LineNr"> 482 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-wrap?
 <span id="L483" class="LineNr"> 483 </span>  <span class="Conceal">¦</span> <span class="Comment"># and if next character isn't newline</span>
-<span id="L484" class="LineNr"> 484 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L485" class="LineNr"> 485 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L484" class="LineNr"> 484 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
+<span id="L485" class="LineNr"> 485 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L25'>next</a>
 <span id="L486" class="LineNr"> 486 </span>  <span class="Conceal">¦</span> next-character:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
 <span id="L487" class="LineNr"> 487 </span>  <span class="Conceal">¦</span> newline?:bool <span class="Special">&lt;-</span> equal next-character, <span class="Constant">10/newline</span>
 <span id="L488" class="LineNr"> 488 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> newline?
@@ -783,11 +783,11 @@ if ('onhashchange' in window) {
 <span id="L721" class="LineNr"> 721 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> move-to-previous-character?
 <span id="L722" class="LineNr"> 722 </span>  <span class="Conceal">¦</span> trace<span class="Constant"> 10</span>, <span class="Constant">[app]</span>, <span class="Constant">[left arrow]</span>
 <span id="L723" class="LineNr"> 723 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not at start of text (before-cursor at § sentinel)</span>
-<span id="L724" class="LineNr"> 724 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> before-cursor
-<span id="L725" class="LineNr"> 725 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L36'>prev</a>, <span class="Constant">0/don't-render</span>
+<span id="L724" class="LineNr"> 724 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L32'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> before-cursor
+<span id="L725" class="LineNr"> 725 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L32'>prev</a>, <span class="Constant">0/don't-render</span>
 <span id="L726" class="LineNr"> 726 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;begin-move-cursor&gt;</span>
 <span id="L727" class="LineNr"> 727 </span>  <span class="Conceal">¦</span> go-render? <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L156'>move-cursor-coordinates-left</a> editor
-<span id="L728" class="LineNr"> 728 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L728" class="LineNr"> 728 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L729" class="LineNr"> 729 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L730" class="LineNr"> 730 </span>  <span class="Conceal">¦</span> undo-coalesce-tag:num <span class="Special">&lt;-</span> copy <span class="Constant">1/left-arrow</span>
 <span id="L731" class="LineNr"> 731 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;end-move-cursor&gt;</span>
@@ -1100,7 +1100,7 @@ if ('onhashchange' in window) {
 <span id="L1038" class="LineNr">1038 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
 <span id="L1039" class="LineNr">1039 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, target-column
 <span id="L1040" class="LineNr">1040 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
-<span id="L1041" class="LineNr">1041 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L1041" class="LineNr">1041 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L1042" class="LineNr">1042 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
 <span id="L1043" class="LineNr">1043 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> currc:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
 <span id="L1044" class="LineNr">1044 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal currc, <span class="Constant">10/newline</span>
@@ -1435,9 +1435,9 @@ if ('onhashchange' in window) {
 <span id="L1373" class="LineNr">1373 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">jump</span> <span class="Constant">+try-to-scroll</span>
 <span id="L1374" class="LineNr">1374 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L1375" class="LineNr">1375 </span>  <span class="Delimiter">}</span>
-<span id="L1376" class="LineNr">1376 </span>  <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L1376" class="LineNr">1376 </span>  <a href='../065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L1377" class="LineNr">1377 </span>  <span class="Delimiter">{</span>
-<span id="L1378" class="LineNr">1378 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L1378" class="LineNr">1378 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> <a href='../065duplex_list.mu.html#L25'>next</a>
 <span id="L1379" class="LineNr">1379 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
 <span id="L1380" class="LineNr">1380 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-bottom-of-screen?
 <span id="L1381" class="LineNr">1381 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
@@ -1454,19 +1454,19 @@ if ('onhashchange' in window) {
 <span id="L1392" class="LineNr">1392 </span>  <span class="Conceal">¦</span> target-column:num <span class="Special">&lt;-</span> copy cursor-column
 <span id="L1393" class="LineNr">1393 </span>  <span class="Conceal">¦</span> <span class="Comment"># scan to start of next line</span>
 <span id="L1394" class="LineNr">1394 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
-<span id="L1395" class="LineNr">1395 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L1396" class="LineNr">1396 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L1395" class="LineNr">1395 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
+<span id="L1396" class="LineNr">1396 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L25'>next</a>
 <span id="L1397" class="LineNr">1397 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, right
 <span id="L1398" class="LineNr">1398 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
 <span id="L1399" class="LineNr">1399 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
-<span id="L1400" class="LineNr">1400 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L1400" class="LineNr">1400 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L25'>next</a>
 <span id="L1401" class="LineNr">1401 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
 <span id="L1402" class="LineNr">1402 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
 <span id="L1403" class="LineNr">1403 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
 <span id="L1404" class="LineNr">1404 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L1405" class="LineNr">1405 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L1406" class="LineNr">1406 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
-<span id="L1407" class="LineNr">1407 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L1407" class="LineNr">1407 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> <a href='../065duplex_list.mu.html#L25'>next</a>
 <span id="L1408" class="LineNr">1408 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
 <span id="L1409" class="LineNr">1409 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-bottom-of-screen?
 <span id="L1410" class="LineNr">1410 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">return</span> <span class="Constant">0/don't-render</span>
@@ -1479,15 +1479,15 @@ if ('onhashchange' in window) {
 <span id="L1417" class="LineNr">1417 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> add cursor-row,<span class="Constant"> 1</span>
 <span id="L1418" class="LineNr">1418 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> copy left
 <span id="L1419" class="LineNr">1419 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
-<span id="L1420" class="LineNr">1420 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L1421" class="LineNr">1421 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L1420" class="LineNr">1420 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
+<span id="L1421" class="LineNr">1421 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L25'>next</a>
 <span id="L1422" class="LineNr">1422 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
 <span id="L1423" class="LineNr">1423 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
 <span id="L1424" class="LineNr">1424 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
 <span id="L1425" class="LineNr">1425 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal cursor-column, target-column
 <span id="L1426" class="LineNr">1426 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
 <span id="L1427" class="LineNr">1427 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> add cursor-column,<span class="Constant"> 1</span>
-<span id="L1428" class="LineNr">1428 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L1428" class="LineNr">1428 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L25'>next</a>
 <span id="L1429" class="LineNr">1429 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L1430" class="LineNr">1430 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L1431" class="LineNr">1431 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
@@ -1637,7 +1637,7 @@ if ('onhashchange' in window) {
 <span id="L1575" class="LineNr">1575 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> equal col, left
 <span id="L1576" class="LineNr">1576 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
 <span id="L1577" class="LineNr">1577 </span>  <span class="Conceal">¦</span> assert curr, <span class="Constant">[move-to-start-of-line tried to move before start of text]</span>
-<span id="L1578" class="LineNr">1578 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
+<span id="L1578" class="LineNr">1578 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> curr
 <span id="L1579" class="LineNr">1579 </span>  <span class="Conceal">¦</span> col <span class="Special">&lt;-</span> subtract col,<span class="Constant"> 1</span>
 <span id="L1580" class="LineNr">1580 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L1581" class="LineNr">1581 </span>  <span class="Delimiter">}</span>
@@ -1855,8 +1855,8 @@ if ('onhashchange' in window) {
 <span id="L1793" class="LineNr">1793 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
 <span id="L1794" class="LineNr">1794 </span>  <span class="Comment"># while not at end of line, move</span>
 <span id="L1795" class="LineNr">1795 </span>  <span class="Delimiter">{</span>
-<span id="L1796" class="LineNr">1796 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
-<span id="L1797" class="LineNr">1797 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>  <span class="Comment"># end of text</span>
+<span id="L1796" class="LineNr">1796 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
+<span id="L1797" class="LineNr">1797 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L25'>next</a>  <span class="Comment"># end of text</span>
 <span id="L1798" class="LineNr">1798 </span>  <span class="Conceal">¦</span> nextc:char <span class="Special">&lt;-</span> get *next, <span class="Constant">value:offset</span>
 <span id="L1799" class="LineNr">1799 </span>  <span class="Conceal">¦</span> at-end-of-line?:bool <span class="Special">&lt;-</span> equal nextc, <span class="Constant">10/newline</span>
 <span id="L1800" class="LineNr">1800 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-end-of-line?
@@ -1864,7 +1864,7 @@ if ('onhashchange' in window) {
 <span id="L1802" class="LineNr">1802 </span>  <span class="Conceal">¦</span> at-right?:bool <span class="Special">&lt;-</span> equal cursor-column, right
 <span id="L1803" class="LineNr">1803 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-right?
 <span id="L1804" class="LineNr">1804 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, cursor-column
-<span id="L1805" class="LineNr">1805 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L1805" class="LineNr">1805 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L25'>next</a>
 <span id="L1806" class="LineNr">1806 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L1807" class="LineNr">1807 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L1808" class="LineNr">1808 </span>  <span class="Delimiter">}</span>
@@ -2043,7 +2043,7 @@ if ('onhashchange' in window) {
 <span id="L1981" class="LineNr">1981 </span>  <span class="Conceal">¦</span> <span class="Comment"># if we have a wrapped line, give up and render the whole screen</span>
 <span id="L1982" class="LineNr">1982 </span>  <span class="Conceal">¦</span> wrap?:bool <span class="Special">&lt;-</span> greater-or-equal i, right
 <span id="L1983" class="LineNr">1983 </span>  <span class="Conceal">¦</span> <span class="muControl">return-if</span> wrap?, <span class="Constant">1/go-render</span>
-<span id="L1984" class="LineNr">1984 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L1984" class="LineNr">1984 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
 <span id="L1985" class="LineNr">1985 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
 <span id="L1986" class="LineNr">1986 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
 <span id="L1987" class="LineNr">1987 </span>  <span class="Conceal">¦</span> b:bool <span class="Special">&lt;-</span> equal c,<span class="Constant"> 10</span>
@@ -2074,7 +2074,7 @@ if ('onhashchange' in window) {
 <span id="L2012" class="LineNr">2012 </span>  update-top-of-screen?:bool <span class="Special">&lt;-</span> copy <span class="Constant">0/false</span>
 <span id="L2013" class="LineNr">2013 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
 <span id="L2014" class="LineNr">2014 </span>  start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy before-cursor
-<span id="L2015" class="LineNr">2015 </span>  end:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L2015" class="LineNr">2015 </span>  end:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L2016" class="LineNr">2016 </span>  <span class="Delimiter">{</span>
 <span id="L2017" class="LineNr">2017 </span>  <span class="Conceal">¦</span> at-start-of-text?:bool <span class="Special">&lt;-</span> equal start, init
 <span id="L2018" class="LineNr">2018 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-start-of-text?
@@ -2084,13 +2084,13 @@ if ('onhashchange' in window) {
 <span id="L2022" class="LineNr">2022 </span>  <span class="Conceal">¦</span> <span class="Comment"># if we went past top-of-screen, make a note to update it as well</span>
 <span id="L2023" class="LineNr">2023 </span>  <span class="Conceal">¦</span> at-top-of-screen?:bool <span class="Special">&lt;-</span> equal start, top-of-screen
 <span id="L2024" class="LineNr">2024 </span>  <span class="Conceal">¦</span> update-top-of-screen?:bool <span class="Special">&lt;-</span> or update-top-of-screen?, at-top-of-screen?
-<span id="L2025" class="LineNr">2025 </span>  <span class="Conceal">¦</span> start <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> start
+<span id="L2025" class="LineNr">2025 </span>  <span class="Conceal">¦</span> start <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> start
 <span id="L2026" class="LineNr">2026 </span>  <span class="Conceal">¦</span> assert start, <span class="Constant">[delete-to-start-of-line tried to move before start of text]</span>
 <span id="L2027" class="LineNr">2027 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L2028" class="LineNr">2028 </span>  <span class="Delimiter">}</span>
 <span id="L2029" class="LineNr">2029 </span>  <span class="Comment"># snip it out</span>
-<span id="L2030" class="LineNr">2030 </span>  result:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> start
-<span id="L2031" class="LineNr">2031 </span>  <a href='../065duplex_list.mu.html#L389'>remove-between</a> start, end
+<span id="L2030" class="LineNr">2030 </span>  result:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> start
+<span id="L2031" class="LineNr">2031 </span>  <a href='../065duplex_list.mu.html#L385'>remove-between</a> start, end
 <span id="L2032" class="LineNr">2032 </span>  <span class="Comment"># update top-of-screen if it's just been invalidated</span>
 <span id="L2033" class="LineNr">2033 </span>  <span class="Delimiter">{</span>
 <span id="L2034" class="LineNr">2034 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> update-top-of-screen?
@@ -2631,19 +2631,19 @@ if ('onhashchange' in window) {
 <span id="L2569" class="LineNr">2569 </span>  <span class="Constant">load-ingredients</span>
 <span id="L2570" class="LineNr">2570 </span>  <span class="Comment"># compute range to delete</span>
 <span id="L2571" class="LineNr">2571 </span>  start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
-<span id="L2572" class="LineNr">2572 </span>  end:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> start
+<span id="L2572" class="LineNr">2572 </span>  end:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> start
 <span id="L2573" class="LineNr">2573 </span>  <span class="Delimiter">{</span>
 <span id="L2574" class="LineNr">2574 </span>  <span class="Conceal">¦</span> at-end-of-text?:bool <span class="Special">&lt;-</span> equal end, <span class="Constant">0/null</span>
 <span id="L2575" class="LineNr">2575 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-end-of-text?
 <span id="L2576" class="LineNr">2576 </span>  <span class="Conceal">¦</span> curr:char <span class="Special">&lt;-</span> get *end, <span class="Constant">value:offset</span>
 <span id="L2577" class="LineNr">2577 </span>  <span class="Conceal">¦</span> at-end-of-line?:bool <span class="Special">&lt;-</span> equal curr, <span class="Constant">10/newline</span>
 <span id="L2578" class="LineNr">2578 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-end-of-line?
-<span id="L2579" class="LineNr">2579 </span>  <span class="Conceal">¦</span> end <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> end
+<span id="L2579" class="LineNr">2579 </span>  <span class="Conceal">¦</span> end <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> end
 <span id="L2580" class="LineNr">2580 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L2581" class="LineNr">2581 </span>  <span class="Delimiter">}</span>
 <span id="L2582" class="LineNr">2582 </span>  <span class="Comment"># snip it out</span>
-<span id="L2583" class="LineNr">2583 </span>  result <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> start
-<span id="L2584" class="LineNr">2584 </span>  <a href='../065duplex_list.mu.html#L389'>remove-between</a> start, end
+<span id="L2583" class="LineNr">2583 </span>  result <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> start
+<span id="L2584" class="LineNr">2584 </span>  <a href='../065duplex_list.mu.html#L385'>remove-between</a> start, end
 <span id="L2585" class="LineNr">2585 </span>]
 <span id="L2586" class="LineNr">2586 </span>
 <span id="L2587" class="LineNr">2587 </span><span class="muScenario">scenario</span> editor-deletes-to-end-of-line-with-ctrl-k-2 [
@@ -2873,7 +2873,7 @@ if ('onhashchange' in window) {
 <span id="L2811" class="LineNr">2811 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
 <span id="L2812" class="LineNr">2812 </span>  <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
 <span id="L2813" class="LineNr">2813 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-newline?
-<span id="L2814" class="LineNr">2814 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L2814" class="LineNr">2814 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
 <span id="L2815" class="LineNr">2815 </span>  <span class="Conceal">¦</span> count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
 <span id="L2816" class="LineNr">2816 </span>  <span class="Delimiter">}</span>
 <span id="L2817" class="LineNr">2817 </span>  <span class="Delimiter">{</span>
@@ -2883,7 +2883,7 @@ if ('onhashchange' in window) {
 <span id="L2821" class="LineNr">2821 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
 <span id="L2822" class="LineNr">2822 </span>  <span class="Conceal">¦</span> at-newline?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
 <span id="L2823" class="LineNr">2823 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-newline?
-<span id="L2824" class="LineNr">2824 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L2824" class="LineNr">2824 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
 <span id="L2825" class="LineNr">2825 </span>  <span class="Conceal">¦</span> count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
 <span id="L2826" class="LineNr">2826 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L2827" class="LineNr">2827 </span>  <span class="Delimiter">}</span>
@@ -3250,9 +3250,9 @@ if ('onhashchange' in window) {
 <span id="L3188" class="LineNr">3188 </span>  <span class="Delimiter">{</span>
 <span id="L3189" class="LineNr">3189 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> len
 <span id="L3190" class="LineNr">3190 </span>  <span class="Conceal">¦</span> <span class="Comment"># empty line; just skip this newline</span>
-<span id="L3191" class="LineNr">3191 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
-<span id="L3192" class="LineNr">3192 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L36'>prev</a>, curr
-<span id="L3193" class="LineNr">3193 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L3191" class="LineNr">3191 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L32'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> curr
+<span id="L3192" class="LineNr">3192 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L32'>prev</a>, curr
+<span id="L3193" class="LineNr">3193 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L3194" class="LineNr">3194 </span>  <span class="Delimiter">}</span>
 <span id="L3195" class="LineNr">3195 </span>  _, max:num <span class="Special">&lt;-</span> divide-with-remainder len, max-line-length
 <span id="L3196" class="LineNr">3196 </span>  <span class="Comment"># remainder 0 =&gt; scan one width-worth</span>
@@ -3266,9 +3266,9 @@ if ('onhashchange' in window) {
 <span id="L3204" class="LineNr">3204 </span>  <span class="Delimiter">{</span>
 <span id="L3205" class="LineNr">3205 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
 <span id="L3206" class="LineNr">3206 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
-<span id="L3207" class="LineNr">3207 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> curr
-<span id="L3208" class="LineNr">3208 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L3209" class="LineNr">3209 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L3207" class="LineNr">3207 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L32'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> curr
+<span id="L3208" class="LineNr">3208 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L32'>prev</a>
+<span id="L3209" class="LineNr">3209 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L3210" class="LineNr">3210 </span>  <span class="Conceal">¦</span> count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
 <span id="L3211" class="LineNr">3211 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L3212" class="LineNr">3212 </span>  <span class="Delimiter">}</span>
@@ -3664,14 +3664,14 @@ if ('onhashchange' in window) {
 <span id="L3602" class="LineNr">3602 </span>  <span class="muControl">return-unless</span> bottom-of-screen
 <span id="L3603" class="LineNr">3603 </span>  <span class="Comment"># if not, position cursor at final character</span>
 <span id="L3604" class="LineNr">3604 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
-<span id="L3605" class="LineNr">3605 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> bottom-of-screen
+<span id="L3605" class="LineNr">3605 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> bottom-of-screen
 <span id="L3606" class="LineNr">3606 </span>  *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L3607" class="LineNr">3607 </span>  <span class="Comment"># keep one line in common with previous page</span>
 <span id="L3608" class="LineNr">3608 </span>  <span class="Delimiter">{</span>
-<span id="L3609" class="LineNr">3609 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L576'>last</a>:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
-<span id="L3610" class="LineNr">3610 </span>  <span class="Conceal">¦</span> newline?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L576'>last</a>, <span class="Constant">10/newline</span>
+<span id="L3609" class="LineNr">3609 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L572'>last</a>:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
+<span id="L3610" class="LineNr">3610 </span>  <span class="Conceal">¦</span> newline?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L572'>last</a>, <span class="Constant">10/newline</span>
 <span id="L3611" class="LineNr">3611 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> newline?:bool
-<span id="L3612" class="LineNr">3612 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> before-cursor
+<span id="L3612" class="LineNr">3612 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> before-cursor
 <span id="L3613" class="LineNr">3613 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L3614" class="LineNr">3614 </span>  <span class="Delimiter">}</span>
 <span id="L3615" class="LineNr">3615 </span>  <span class="Comment"># move cursor and top-of-screen to start of that line</span>
@@ -3695,10 +3695,10 @@ if ('onhashchange' in window) {
 <span id="L3633" class="LineNr">3633 </span>  <span class="Delimiter">{</span>
 <span id="L3634" class="LineNr">3634 </span>  <span class="Conceal">¦</span> at-start-of-text?:bool <span class="Special">&lt;-</span> equal before-cursor, init
 <span id="L3635" class="LineNr">3635 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-start-of-text?
-<span id="L3636" class="LineNr">3636 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a>:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
-<span id="L3637" class="LineNr">3637 </span>  <span class="Conceal">¦</span> at-start-of-line?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L36'>prev</a>, <span class="Constant">10/newline</span>
+<span id="L3636" class="LineNr">3636 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L32'>prev</a>:char <span class="Special">&lt;-</span> get *before-cursor, <span class="Constant">value:offset</span>
+<span id="L3637" class="LineNr">3637 </span>  <span class="Conceal">¦</span> at-start-of-line?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L32'>prev</a>, <span class="Constant">10/newline</span>
 <span id="L3638" class="LineNr">3638 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> at-start-of-line?
-<span id="L3639" class="LineNr">3639 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> before-cursor
+<span id="L3639" class="LineNr">3639 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> before-cursor
 <span id="L3640" class="LineNr">3640 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
 <span id="L3641" class="LineNr">3641 </span>  <span class="Conceal">¦</span> assert before-cursor, <span class="Constant">[move-to-start-of-line tried to move before start of text]</span>
 <span id="L3642" class="LineNr">3642 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
@@ -3888,9 +3888,9 @@ if ('onhashchange' in window) {
 <span id="L3826" class="LineNr">3826 </span>  <span class="Delimiter">{</span>
 <span id="L3827" class="LineNr">3827 </span>  <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal count, max
 <span id="L3828" class="LineNr">3828 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
-<span id="L3829" class="LineNr">3829 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L3175'>before-previous-screen-line</a> top-of-screen, editor
-<span id="L3830" class="LineNr">3830 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L36'>prev</a>
-<span id="L3831" class="LineNr">3831 </span>  <span class="Conceal">¦</span> top-of-screen <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L3829" class="LineNr">3829 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L32'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L3175'>before-previous-screen-line</a> top-of-screen, editor
+<span id="L3830" class="LineNr">3830 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L32'>prev</a>
+<span id="L3831" class="LineNr">3831 </span>  <span class="Conceal">¦</span> top-of-screen <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L3832" class="LineNr">3832 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, top-of-screen
 <span id="L3833" class="LineNr">3833 </span>  <span class="Conceal">¦</span> count <span class="Special">&lt;-</span> add count,<span class="Constant"> 1</span>
 <span id="L3834" class="LineNr">3834 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
@@ -4262,7 +4262,7 @@ if ('onhashchange' in window) {
 <span id="L4200" class="LineNr">4200 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;begin-move-cursor&gt;</span>
 <span id="L4201" class="LineNr">4201 </span>  <span class="Conceal">¦</span> old-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
 <span id="L4202" class="LineNr">4202 </span>  <span class="Conceal">¦</span> cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
-<span id="L4203" class="LineNr">4203 </span>  <span class="Conceal">¦</span> cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> cursor
+<span id="L4203" class="LineNr">4203 </span>  <span class="Conceal">¦</span> cursor <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> cursor
 <span id="L4204" class="LineNr">4204 </span>  <span class="Conceal">¦</span> new-top:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L3175'>before-previous-screen-line</a> cursor, editor
 <span id="L4205" class="LineNr">4205 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">top-of-screen:offset</span>, new-top
 <span id="L4206" class="LineNr">4206 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>,<span class="Constant"> 1</span>
@@ -4283,8 +4283,8 @@ if ('onhashchange' in window) {
 <span id="L4221" class="LineNr">4221 </span>  <span class="Conceal">¦</span> data:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
 <span id="L4222" class="LineNr">4222 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> &lt;begin-insert-character&gt;</span>
 <span id="L4223" class="LineNr">4223 </span>  <span class="Conceal">¦</span> before-line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4280'>before-start-of-screen-line</a> editor
-<span id="L4224" class="LineNr">4224 </span>  <span class="Conceal">¦</span> line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-line-start
-<span id="L4225" class="LineNr">4225 </span>  <span class="Conceal">¦</span> commented-out?:bool <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L589'>match</a> line-start, <span class="Constant">[#? ]</span>  <span class="Comment"># comment prefix</span>
+<span id="L4224" class="LineNr">4224 </span>  <span class="Conceal">¦</span> line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-line-start
+<span id="L4225" class="LineNr">4225 </span>  <span class="Conceal">¦</span> commented-out?:bool <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L585'>match</a> line-start, <span class="Constant">[#? ]</span>  <span class="Comment"># comment prefix</span>
 <span id="L4226" class="LineNr">4226 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
 <span id="L4227" class="LineNr">4227 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> commented-out?
 <span id="L4228" class="LineNr">4228 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># uncomment</span>
@@ -4313,7 +4313,7 @@ if ('onhashchange' in window) {
 <span id="L4251" class="LineNr">4251 </span>  <span class="Constant">local-scope</span>
 <span id="L4252" class="LineNr">4252 </span>  <span class="Constant">load-ingredients</span>
 <span id="L4253" class="LineNr">4253 </span>  before-line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L4280'>before-start-of-screen-line</a> editor
-<span id="L4254" class="LineNr">4254 </span>  line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-line-start
+<span id="L4254" class="LineNr">4254 </span>  line-start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-line-start
 <span id="L4255" class="LineNr">4255 </span>  color:num <span class="Special">&lt;-</span> copy <span class="Constant">7/white</span>
 <span id="L4256" class="LineNr">4256 </span>  left:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">left:offset</span>
 <span id="L4257" class="LineNr">4257 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
@@ -4331,7 +4331,7 @@ if ('onhashchange' in window) {
 <span id="L4269" class="LineNr">4269 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> newline?
 <span id="L4270" class="LineNr">4270 </span>  <span class="Conceal">¦</span> color <span class="Special">&lt;-</span> <a href='001-editor.mu.html#L397'>get-color</a> color, c
 <span id="L4271" class="LineNr">4271 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L16'>screen</a>, c, color
-<span id="L4272" class="LineNr">4272 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L4272" class="LineNr">4272 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
 <span id="L4273" class="LineNr">4273 </span>  <span class="Conceal">¦</span> i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
 <span id="L4274" class="LineNr">4274 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L4275" class="LineNr">4275 </span>  <span class="Delimiter">}</span>
@@ -4344,9 +4344,9 @@ if ('onhashchange' in window) {
 <span id="L4282" class="LineNr">4282 </span>  <span class="Constant">load-ingredients</span>
 <span id="L4283" class="LineNr">4283 </span>  cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
 <span id="L4284" class="LineNr">4284 </span>  <span class="Delimiter">{</span>
-<span id="L4285" class="LineNr">4285 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> cursor
-<span id="L4286" class="LineNr">4286 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>
-<span id="L4287" class="LineNr">4287 </span>  <span class="Conceal">¦</span> cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L29'>next</a>
+<span id="L4285" class="LineNr">4285 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> cursor
+<span id="L4286" class="LineNr">4286 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> <a href='../065duplex_list.mu.html#L25'>next</a>
+<span id="L4287" class="LineNr">4287 </span>  <span class="Conceal">¦</span> cursor <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L25'>next</a>
 <span id="L4288" class="LineNr">4288 </span>  <span class="Delimiter">}</span>
 <span id="L4289" class="LineNr">4289 </span>  result <span class="Special">&lt;-</span> <a href='003-shortcuts.mu.html#L3175'>before-previous-screen-line</a> cursor, editor
 <span id="L4290" class="LineNr">4290 </span>]
diff --git a/html/edit/004-programming-environment.mu.html b/html/edit/004-programming-environment.mu.html
index e6eac4eb..6179ca5e 100644
--- a/html/edit/004-programming-environment.mu.html
+++ b/html/edit/004-programming-environment.mu.html
@@ -226,8 +226,8 @@ if ('onhashchange' in window) {
 <span id="L163" class="LineNr">163 </span>  <a href='../081print.mu.html#L782'>screen-height</a>:num <span class="Special">&lt;-</span> <a href='../081print.mu.html#L782'>screen-height</a> <a href='../081print.mu.html#L16'>screen</a>
 <span id="L164" class="LineNr">164 </span>  right:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">right:offset</span>
 <span id="L165" class="LineNr">165 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
-<span id="L166" class="LineNr">166 </span>  <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy curr  <span class="Comment"># just in case curr becomes null and we can't compute prev</span>
-<span id="L167" class="LineNr">167 </span>  curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L166" class="LineNr">166 </span>  <a href='../065duplex_list.mu.html#L32'>prev</a>:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> copy curr  <span class="Comment"># just in case curr becomes null and we can't compute prev</span>
+<span id="L167" class="LineNr">167 </span>  curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
 <span id="L168" class="LineNr">168 </span>  color:num <span class="Special">&lt;-</span> copy <span class="Constant">7/white</span>
 <span id="L169" class="LineNr">169 </span>  row:num <span class="Special">&lt;-</span> copy <span class="Constant">1/top</span>
 <span id="L170" class="LineNr">170 </span>  column:num <span class="Special">&lt;-</span> copy left
@@ -249,7 +249,7 @@ if ('onhashchange' in window) {
 <span id="L186" class="LineNr">186 </span>  <span class="Conceal">¦</span> <span class="Comment"># editor.cursor-row and editor.cursor-column based on</span>
 <span id="L187" class="LineNr">187 </span>  <span class="Conceal">¦</span> <span class="Comment"># old-before-cursor</span>
 <span id="L188" class="LineNr">188 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
-<span id="L189" class="LineNr">189 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-cursor?:bool <span class="Special">&lt;-</span> equal old-before-cursor, <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L189" class="LineNr">189 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> at-cursor?:bool <span class="Special">&lt;-</span> equal old-before-cursor, <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L190" class="LineNr">190 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-cursor?
 <span id="L191" class="LineNr">191 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, row
 <span id="L192" class="LineNr">192 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-column:offset</span>, column
@@ -267,8 +267,8 @@ if ('onhashchange' in window) {
 <span id="L204" class="LineNr">204 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> row <span class="Special">&lt;-</span> add row,<span class="Constant"> 1</span>
 <span id="L205" class="LineNr">205 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> copy left
 <span id="L206" class="LineNr">206 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../081print.mu.html#L16'>screen</a> <span class="Special">&lt;-</span> move-cursor <a href='../081print.mu.html#L16'>screen</a>, row, column
-<span id="L207" class="LineNr">207 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L208" class="LineNr">208 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L207" class="LineNr">207 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
+<span id="L208" class="LineNr">208 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L32'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L209" class="LineNr">209 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
 <span id="L210" class="LineNr">210 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L211" class="LineNr">211 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
@@ -286,8 +286,8 @@ if ('onhashchange' in window) {
 <span id="L223" class="LineNr">223 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
 <span id="L224" class="LineNr">224 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L225" class="LineNr">225 </span>  <span class="Conceal">¦</span> print <a href='../081print.mu.html#L16'>screen</a>, c, color
-<span id="L226" class="LineNr">226 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
-<span id="L227" class="LineNr">227 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> <a href='../065duplex_list.mu.html#L36'>prev</a>
+<span id="L226" class="LineNr">226 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
+<span id="L227" class="LineNr">227 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L32'>prev</a> <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> <a href='../065duplex_list.mu.html#L32'>prev</a>
 <span id="L228" class="LineNr">228 </span>  <span class="Conceal">¦</span> column <span class="Special">&lt;-</span> add column,<span class="Constant"> 1</span>
 <span id="L229" class="LineNr">229 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L230" class="LineNr">230 </span>  <span class="Delimiter">}</span>
diff --git a/html/edit/005-sandbox.mu.html b/html/edit/005-sandbox.mu.html
index 5272c8bd..1c6ab31c 100644
--- a/html/edit/005-sandbox.mu.html
+++ b/html/edit/005-sandbox.mu.html
@@ -541,7 +541,7 @@ if ('onhashchange' in window) {
 <span id="L478" class="LineNr"> 478 </span>  <span class="Comment"># read all scenarios, pushing them to end of a list of scenarios</span>
 <span id="L479" class="LineNr"> 479 </span>  idx:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
 <span id="L480" class="LineNr"> 480 </span>  curr:&amp;:sandbox <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
-<span id="L481" class="LineNr"> 481 </span>  <a href='../065duplex_list.mu.html#L36'>prev</a>:&amp;:sandbox <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
+<span id="L481" class="LineNr"> 481 </span>  <a href='../065duplex_list.mu.html#L32'>prev</a>:&amp;:sandbox <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
 <span id="L482" class="LineNr"> 482 </span>  <span class="Delimiter">{</span>
 <span id="L483" class="LineNr"> 483 </span>  <span class="Conceal">¦</span> filename:text <span class="Special">&lt;-</span> append <span class="Constant">[lesson/]</span>, idx
 <span id="L484" class="LineNr"> 484 </span>  <span class="Conceal">¦</span> contents:text <span class="Special">&lt;-</span> <a href='../088file.mu.html#L38'>slurp</a> <a href='../088file.mu.html#L11'>resources</a>, filename
@@ -560,7 +560,7 @@ if ('onhashchange' in window) {
 <span id="L497" class="LineNr"> 497 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> *prev <span class="Special">&lt;-</span> put *prev, <span class="Constant">next-sandbox:offset</span>, curr
 <span id="L498" class="LineNr"> 498 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L499" class="LineNr"> 499 </span>  <span class="Conceal">¦</span> idx <span class="Special">&lt;-</span> add idx,<span class="Constant"> 1</span>
-<span id="L500" class="LineNr"> 500 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L36'>prev</a> <span class="Special">&lt;-</span> copy curr
+<span id="L500" class="LineNr"> 500 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L32'>prev</a> <span class="Special">&lt;-</span> copy curr
 <span id="L501" class="LineNr"> 501 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L502" class="LineNr"> 502 </span>  <span class="Delimiter">}</span>
 <span id="L503" class="LineNr"> 503 </span>  <span class="Comment"># update sandbox count</span>
@@ -750,13 +750,13 @@ if ('onhashchange' in window) {
 <span id="L687" class="LineNr"> 687 </span>  curr:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
 <span id="L688" class="LineNr"> 688 </span>  <span class="Comment"># skip § sentinel</span>
 <span id="L689" class="LineNr"> 689 </span>  assert curr, <span class="Constant">[editor without data is illegal; must have at least a sentinel]</span>
-<span id="L690" class="LineNr"> 690 </span>  curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L690" class="LineNr"> 690 </span>  curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
 <span id="L691" class="LineNr"> 691 </span>  <span class="muControl">return-unless</span> curr,<span class="Constant"> 0</span>
 <span id="L692" class="LineNr"> 692 </span>  <span class="Delimiter">{</span>
 <span id="L693" class="LineNr"> 693 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> curr
 <span id="L694" class="LineNr"> 694 </span>  <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> get *curr, <span class="Constant">value:offset</span>
 <span id="L695" class="LineNr"> 695 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> append buf, c
-<span id="L696" class="LineNr"> 696 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> curr
+<span id="L696" class="LineNr"> 696 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> curr
 <span id="L697" class="LineNr"> 697 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L698" class="LineNr"> 698 </span>  <span class="Delimiter">}</span>
 <span id="L699" class="LineNr"> 699 </span>  result <span class="Special">&lt;-</span> <a href='../061text.mu.html#L338'>buffer-to-array</a> buf
@@ -1010,13 +1010,13 @@ if ('onhashchange' in window) {
 <span id="L947" class="LineNr"> 947 </span>  <span class="Constant">load-ingredients</span>
 <span id="L948" class="LineNr"> 948 </span>  curr:&amp;:sandbox <span class="Special">&lt;-</span> get *env, <span class="Constant">sandbox:offset</span>
 <span id="L949" class="LineNr"> 949 </span>  <span class="muControl">return-unless</span> curr, <span class="Constant">0/nil</span>
-<span id="L950" class="LineNr"> 950 </span>  <a href='../065duplex_list.mu.html#L29'>next</a>:&amp;:sandbox <span class="Special">&lt;-</span> get *curr, <span class="Constant">next-sandbox:offset</span>
+<span id="L950" class="LineNr"> 950 </span>  <a href='../065duplex_list.mu.html#L25'>next</a>:&amp;:sandbox <span class="Special">&lt;-</span> get *curr, <span class="Constant">next-sandbox:offset</span>
 <span id="L951" class="LineNr"> 951 </span>  <span class="Delimiter">{</span>
-<span id="L952" class="LineNr"> 952 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L29'>next</a>, <span class="Constant">0/nil</span>
-<span id="L953" class="LineNr"> 953 </span>  <span class="Conceal">¦</span> found?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L29'>next</a>, in
+<span id="L952" class="LineNr"> 952 </span>  <span class="Conceal">¦</span> <span class="muControl">return-unless</span> <a href='../065duplex_list.mu.html#L25'>next</a>, <span class="Constant">0/nil</span>
+<span id="L953" class="LineNr"> 953 </span>  <span class="Conceal">¦</span> found?:bool <span class="Special">&lt;-</span> equal <a href='../065duplex_list.mu.html#L25'>next</a>, in
 <span id="L954" class="LineNr"> 954 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> found?
-<span id="L955" class="LineNr"> 955 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L29'>next</a>
-<span id="L956" class="LineNr"> 956 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L29'>next</a> <span class="Special">&lt;-</span> get *curr, <span class="Constant">next-sandbox:offset</span>
+<span id="L955" class="LineNr"> 955 </span>  <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> copy <a href='../065duplex_list.mu.html#L25'>next</a>
+<span id="L956" class="LineNr"> 956 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L25'>next</a> <span class="Special">&lt;-</span> get *curr, <span class="Constant">next-sandbox:offset</span>
 <span id="L957" class="LineNr"> 957 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
 <span id="L958" class="LineNr"> 958 </span>  <span class="Delimiter">}</span>
 <span id="L959" class="LineNr"> 959 </span>  <span class="muControl">return</span> curr
diff --git a/html/edit/006-sandbox-copy.mu.html b/html/edit/006-sandbox-copy.mu.html
index 6849cf9f..64332fb3 100644
--- a/html/edit/006-sandbox-copy.mu.html
+++ b/html/edit/006-sandbox-copy.mu.html
@@ -266,7 +266,7 @@ if ('onhashchange' in window) {
 <span id="L204" class="LineNr">204 </span>  <span class="Constant">local-scope</span>
 <span id="L205" class="LineNr">205 </span>  <span class="Constant">load-ingredients</span>
 <span id="L206" class="LineNr">206 </span>  head:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
-<span id="L207" class="LineNr">207 </span>  first:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> head
+<span id="L207" class="LineNr">207 </span>  first:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> head
 <span id="L208" class="LineNr">208 </span>  result <span class="Special">&lt;-</span> not first
 <span id="L209" class="LineNr">209 </span>]
 <span id="L210" class="LineNr">210 </span>
diff --git a/html/edit/011-errors.mu.html b/html/edit/011-errors.mu.html
index 8349e70d..790ec76c 100644
--- a/html/edit/011-errors.mu.html
+++ b/html/edit/011-errors.mu.html
@@ -480,7 +480,7 @@ if ('onhashchange' in window) {
 <span id="L417" class="LineNr">417 </span>  <span class="Conceal">¦</span><span class="Constant"> .  x &lt;- copy 0                                     ╎─────────────────────────────────────────────────.</span>
 <span id="L418" class="LineNr">418 </span>  <span class="Conceal">¦</span><span class="Constant"> .]                                                 ╎                                                 .</span>
 <span id="L419" class="LineNr">419 </span>  <span class="Conceal">¦</span><span class="Constant"> .foo: missing type for 'x' in 'x &lt;- copy 0'        ╎                                                 .</span>
-<span id="L420" class="LineNr">420 </span>  <span class="Conceal">¦</span><span class="Constant"> .foo: can't copy '0' to 'x'; types don't <a href='../065duplex_list.mu.html#L589'>match</a>     ╎                                                 .</span>
+<span id="L420" class="LineNr">420 </span>  <span class="Conceal">¦</span><span class="Constant"> .foo: can't copy '0' to 'x'; types don't <a href='../065duplex_list.mu.html#L585'>match</a>     ╎                                                 .</span>
 <span id="L421" class="LineNr">421 </span>  <span class="Conceal">¦</span><span class="Constant"> .╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╎                                                 .</span>
 <span id="L422" class="LineNr">422 </span>  <span class="Conceal">¦</span><span class="Constant"> .                                                  ╎                                                 .</span>
 <span id="L423" class="LineNr">423 </span>  ]
diff --git a/html/edit/012-editor-undo.mu.html b/html/edit/012-editor-undo.mu.html
index 7774741c..dcf95a50 100644
--- a/html/edit/012-editor-undo.mu.html
+++ b/html/edit/012-editor-undo.mu.html
@@ -133,7 +133,7 @@ if ('onhashchange' in window) {
 <span id="L70" class="LineNr">  70 </span>  <span class="Conceal">¦</span> undo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
 <span id="L71" class="LineNr">  71 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> undo
 <span id="L72" class="LineNr">  72 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first undo
-<span id="L73" class="LineNr">  73 </span>  <span class="Conceal">¦</span> undo <span class="Special">&lt;-</span> <a href='../064list.mu.html#L25'>rest</a> undo
+<span id="L73" class="LineNr">  73 </span>  <span class="Conceal">¦</span> undo <span class="Special">&lt;-</span> <a href='../064list.mu.html#L24'>rest</a> undo
 <span id="L74" class="LineNr">  74 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">undo:offset</span>, undo
 <span id="L75" class="LineNr">  75 </span>  <span class="Conceal">¦</span> redo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">redo:offset</span>
 <span id="L76" class="LineNr">  76 </span>  <span class="Conceal">¦</span> redo <span class="Special">&lt;-</span> push op, redo
@@ -151,7 +151,7 @@ if ('onhashchange' in window) {
 <span id="L88" class="LineNr">  88 </span>  <span class="Conceal">¦</span> redo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">redo:offset</span>
 <span id="L89" class="LineNr">  89 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> redo
 <span id="L90" class="LineNr">  90 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> first redo
-<span id="L91" class="LineNr">  91 </span>  <span class="Conceal">¦</span> redo <span class="Special">&lt;-</span> <a href='../064list.mu.html#L25'>rest</a> redo
+<span id="L91" class="LineNr">  91 </span>  <span class="Conceal">¦</span> redo <span class="Special">&lt;-</span> <a href='../064list.mu.html#L24'>rest</a> redo
 <span id="L92" class="LineNr">  92 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">redo:offset</span>, redo
 <span id="L93" class="LineNr">  93 </span>  <span class="Conceal">¦</span> undo:&amp;:<a href='../064list.mu.html#L6'>list</a>:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> get *editor, <span class="Constant">undo:offset</span>
 <span id="L94" class="LineNr">  94 </span>  <span class="Conceal">¦</span> undo <span class="Special">&lt;-</span> push op, undo
@@ -221,7 +221,7 @@ if ('onhashchange' in window) {
 <span id="L158" class="LineNr"> 158 </span>  <span class="Conceal">¦</span> previous-coalesce-tag:num <span class="Special">&lt;-</span> get typing, <span class="Constant">tag:offset</span>
 <span id="L159" class="LineNr"> 159 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> previous-coalesce-tag
 <span id="L160" class="LineNr"> 160 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
-<span id="L161" class="LineNr"> 161 </span>  <span class="Conceal">¦</span> insert-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L161" class="LineNr"> 161 </span>  <span class="Conceal">¦</span> insert-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L162" class="LineNr"> 162 </span>  <span class="Conceal">¦</span> typing <span class="Special">&lt;-</span> put typing, <span class="Constant">insert-until:offset</span>, insert-until
 <span id="L163" class="LineNr"> 163 </span>  <span class="Conceal">¦</span> typing <span class="Special">&lt;-</span> put typing, <span class="Constant">after-row:offset</span>, cursor-row
 <span id="L164" class="LineNr"> 164 </span>  <span class="Conceal">¦</span> typing <span class="Special">&lt;-</span> put typing, <span class="Constant">after-column:offset</span>, cursor-column
@@ -230,8 +230,8 @@ if ('onhashchange' in window) {
 <span id="L167" class="LineNr"> 167 </span>  <span class="Conceal">¦</span> <span class="muControl">break</span> <span class="Constant">+done-adding-insert-operation</span>
 <span id="L168" class="LineNr"> 168 </span>  <span class="Delimiter">}</span>
 <span id="L169" class="LineNr"> 169 </span>  <span class="Comment"># if not, create a new operation</span>
-<span id="L170" class="LineNr"> 170 </span>  insert-from:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> cursor-before
-<span id="L171" class="LineNr"> 171 </span>  insert-to:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> insert-from
+<span id="L170" class="LineNr"> 170 </span>  insert-from:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> cursor-before
+<span id="L171" class="LineNr"> 171 </span>  insert-to:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> insert-from
 <span id="L172" class="LineNr"> 172 </span>  op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
 <span id="L173" class="LineNr"> 173 </span>  *op <span class="Special">&lt;-</span> merge <span class="Constant">0/insert-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, insert-from, insert-to, <span class="Constant">1/coalesce</span>
 <span id="L174" class="LineNr"> 174 </span>  editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L202'>add-operation</a> editor, op
@@ -250,9 +250,9 @@ if ('onhashchange' in window) {
 <span id="L187" class="LineNr"> 187 </span>  cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
 <span id="L188" class="LineNr"> 188 </span>  cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
 <span id="L189" class="LineNr"> 189 </span>  <span class="Comment"># never coalesce</span>
-<span id="L190" class="LineNr"> 190 </span>  insert-from:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> cursor-before
+<span id="L190" class="LineNr"> 190 </span>  insert-from:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> cursor-before
 <span id="L191" class="LineNr"> 191 </span>  before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
-<span id="L192" class="LineNr"> 192 </span>  insert-to:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L192" class="LineNr"> 192 </span>  insert-to:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L193" class="LineNr"> 193 </span>  op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
 <span id="L194" class="LineNr"> 194 </span>  *op <span class="Special">&lt;-</span> merge <span class="Constant">0/insert-operation</span>, cursor-row-before, cursor-column-before, top-before, cursor-row/after, cursor-column/after, top-after, insert-from, insert-to, <span class="Constant">0/never-coalesce</span>
 <span id="L195" class="LineNr"> 195 </span>  editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L202'>add-operation</a> editor, op
@@ -280,9 +280,9 @@ if ('onhashchange' in window) {
 <span id="L217" class="LineNr"> 217 </span>  <span class="Conceal">¦</span> start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get typing, <span class="Constant">insert-from:offset</span>
 <span id="L218" class="LineNr"> 218 </span>  <span class="Conceal">¦</span> end:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get typing, <span class="Constant">insert-until:offset</span>
 <span id="L219" class="LineNr"> 219 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
-<span id="L220" class="LineNr"> 220 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L36'>prev</a> start
+<span id="L220" class="LineNr"> 220 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L32'>prev</a> start
 <span id="L221" class="LineNr"> 221 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">before-cursor:offset</span>, before-cursor
-<span id="L222" class="LineNr"> 222 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L389'>remove-between</a> before-cursor, end
+<span id="L222" class="LineNr"> 222 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L385'>remove-between</a> before-cursor, end
 <span id="L223" class="LineNr"> 223 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get typing, <span class="Constant">before-row:offset</span>
 <span id="L224" class="LineNr"> 224 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
 <span id="L225" class="LineNr"> 225 </span>  <span class="Conceal">¦</span> cursor-column <span class="Special">&lt;-</span> get typing, <span class="Constant">before-column:offset</span>
@@ -480,7 +480,7 @@ if ('onhashchange' in window) {
 <span id="L417" class="LineNr"> 417 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
 <span id="L418" class="LineNr"> 418 </span>  <span class="Conceal">¦</span> insert-from:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get typing, <span class="Constant">insert-from:offset</span>  <span class="Comment"># ignore insert-to because it's already been spliced away</span>
 <span id="L419" class="LineNr"> 419 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert insert-to matches next(before-cursor)</span>
-<span id="L420" class="LineNr"> 420 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L529'>splice</a> before-cursor, insert-from
+<span id="L420" class="LineNr"> 420 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L525'>splice</a> before-cursor, insert-from
 <span id="L421" class="LineNr"> 421 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
 <span id="L422" class="LineNr"> 422 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get typing, <span class="Constant">after-row:offset</span>
 <span id="L423" class="LineNr"> 423 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
@@ -1701,7 +1701,7 @@ if ('onhashchange' in window) {
 <span id="L1638" class="LineNr">1638 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> coalesce?
 <span id="L1639" class="LineNr">1639 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">delete-from:offset</span>, before-cursor
 <span id="L1640" class="LineNr">1640 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> backspaced-so-far:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">deleted-text:offset</span>
-<span id="L1641" class="LineNr">1641 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L529'>splice</a> backspaced-cell, backspaced-so-far
+<span id="L1641" class="LineNr">1641 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L525'>splice</a> backspaced-cell, backspaced-so-far
 <span id="L1642" class="LineNr">1642 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">deleted-text:offset</span>, backspaced-cell
 <span id="L1643" class="LineNr">1643 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-row:offset</span>, cursor-row
 <span id="L1644" class="LineNr">1644 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">after-column:offset</span>, cursor-column
@@ -1711,7 +1711,7 @@ if ('onhashchange' in window) {
 <span id="L1648" class="LineNr">1648 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L1649" class="LineNr">1649 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not, create a new operation</span>
 <span id="L1650" class="LineNr">1650 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
-<span id="L1651" class="LineNr">1651 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L1651" class="LineNr">1651 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L1652" class="LineNr">1652 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, backspaced-cell/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">1/coalesce-backspace</span>
 <span id="L1653" class="LineNr">1653 </span>  <span class="Conceal">¦</span> editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L202'>add-operation</a> editor, op
 <span id="L1654" class="LineNr">1654 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +done-adding-backspace-operation</span>
@@ -1725,8 +1725,8 @@ if ('onhashchange' in window) {
 <span id="L1662" class="LineNr">1662 </span>  <span class="Conceal">¦</span> anchor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">delete-from:offset</span>
 <span id="L1663" class="LineNr">1663 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> anchor
 <span id="L1664" class="LineNr">1664 </span>  <span class="Conceal">¦</span> deleted:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">deleted-text:offset</span>
-<span id="L1665" class="LineNr">1665 </span>  <span class="Conceal">¦</span> old-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L576'>last</a> deleted
-<span id="L1666" class="LineNr">1666 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L529'>splice</a> anchor, deleted
+<span id="L1665" class="LineNr">1665 </span>  <span class="Conceal">¦</span> old-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L572'>last</a> deleted
+<span id="L1666" class="LineNr">1666 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L525'>splice</a> anchor, deleted
 <span id="L1667" class="LineNr">1667 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
 <span id="L1668" class="LineNr">1668 </span>  <span class="Conceal">¦</span> before-cursor <span class="Special">&lt;-</span> copy old-cursor
 <span id="L1669" class="LineNr">1669 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get deletion, <span class="Constant">before-row:offset</span>
@@ -1745,7 +1745,7 @@ if ('onhashchange' in window) {
 <span id="L1682" class="LineNr">1682 </span>  <span class="Conceal">¦</span> start:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">delete-from:offset</span>
 <span id="L1683" class="LineNr">1683 </span>  <span class="Conceal">¦</span> end:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">delete-until:offset</span>
 <span id="L1684" class="LineNr">1684 </span>  <span class="Conceal">¦</span> data:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">data:offset</span>
-<span id="L1685" class="LineNr">1685 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L389'>remove-between</a> start, end
+<span id="L1685" class="LineNr">1685 </span>  <span class="Conceal">¦</span> <a href='../065duplex_list.mu.html#L385'>remove-between</a> start, end
 <span id="L1686" class="LineNr">1686 </span>  <span class="Conceal">¦</span> <span class="Comment"># assert cursor-row/cursor-column/top-of-screen match after-row/after-column/after-top-of-screen</span>
 <span id="L1687" class="LineNr">1687 </span>  <span class="Conceal">¦</span> cursor-row <span class="Special">&lt;-</span> get deletion, <span class="Constant">after-row:offset</span>
 <span id="L1688" class="LineNr">1688 </span>  <span class="Conceal">¦</span> *editor <span class="Special">&lt;-</span> put *editor, <span class="Constant">cursor-row:offset</span>, cursor-row
@@ -1925,7 +1925,7 @@ if ('onhashchange' in window) {
 <span id="L1862" class="LineNr">1862 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> previous-coalesce-tag:num <span class="Special">&lt;-</span> get deletion, <span class="Constant">tag:offset</span>
 <span id="L1863" class="LineNr">1863 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> coalesce?:bool <span class="Special">&lt;-</span> equal previous-coalesce-tag, <span class="Constant">2/coalesce-delete</span>
 <span id="L1864" class="LineNr">1864 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> coalesce?
-<span id="L1865" class="LineNr">1865 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> delete-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L1865" class="LineNr">1865 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> delete-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L1866" class="LineNr">1866 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deletion <span class="Special">&lt;-</span> put deletion, <span class="Constant">delete-until:offset</span>, delete-until
 <span id="L1867" class="LineNr">1867 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deleted-so-far:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get deletion, <span class="Constant">deleted-text:offset</span>
 <span id="L1868" class="LineNr">1868 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> deleted-so-far <span class="Special">&lt;-</span> append deleted-so-far, deleted-cell
@@ -1938,7 +1938,7 @@ if ('onhashchange' in window) {
 <span id="L1875" class="LineNr">1875 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L1876" class="LineNr">1876 </span>  <span class="Conceal">¦</span> <span class="Comment"># if not, create a new operation</span>
 <span id="L1877" class="LineNr">1877 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
-<span id="L1878" class="LineNr">1878 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L1878" class="LineNr">1878 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L1879" class="LineNr">1879 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, deleted-cell/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">2/coalesce-delete</span>
 <span id="L1880" class="LineNr">1880 </span>  <span class="Conceal">¦</span> editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L202'>add-operation</a> editor, op
 <span id="L1881" class="LineNr">1881 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> +done-adding-delete-operation</span>
@@ -2040,7 +2040,7 @@ if ('onhashchange' in window) {
 <span id="L1977" class="LineNr">1977 </span>  <span class="Conceal">¦</span> top-after:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
 <span id="L1978" class="LineNr">1978 </span>  <span class="Conceal">¦</span> cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
 <span id="L1979" class="LineNr">1979 </span>  <span class="Conceal">¦</span> cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
-<span id="L1980" class="LineNr">1980 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L1980" class="LineNr">1980 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L1981" class="LineNr">1981 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
 <span id="L1982" class="LineNr">1982 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, deleted-cells/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">0/never-coalesce</span>
 <span id="L1983" class="LineNr">1983 </span>  <span class="Conceal">¦</span> editor <span class="Special">&lt;-</span> <a href='012-editor-undo.mu.html#L202'>add-operation</a> editor, op
@@ -2143,7 +2143,7 @@ if ('onhashchange' in window) {
 <span id="L2080" class="LineNr">2080 </span>  <span class="Conceal">¦</span> top-after:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">top-of-screen:offset</span>
 <span id="L2081" class="LineNr">2081 </span>  <span class="Conceal">¦</span> op:&amp;:<a href='012-editor-undo.mu.html#L5'>operation</a> <span class="Special">&lt;-</span> new <span class="Constant"><a href='012-editor-undo.mu.html#L5'>operation</a>:type</span>
 <span id="L2082" class="LineNr">2082 </span>  <span class="Conceal">¦</span> before-cursor:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> get *editor, <span class="Constant">before-cursor:offset</span>
-<span id="L2083" class="LineNr">2083 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L29'>next</a> before-cursor
+<span id="L2083" class="LineNr">2083 </span>  <span class="Conceal">¦</span> deleted-until:&amp;:<a href='../065duplex_list.mu.html#L3'>duplex-list</a>:char <span class="Special">&lt;-</span> <a href='../065duplex_list.mu.html#L25'>next</a> before-cursor
 <span id="L2084" class="LineNr">2084 </span>  <span class="Conceal">¦</span> cursor-row:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-row:offset</span>
 <span id="L2085" class="LineNr">2085 </span>  <span class="Conceal">¦</span> cursor-column:num <span class="Special">&lt;-</span> get *editor, <span class="Constant">cursor-column:offset</span>
 <span id="L2086" class="LineNr">2086 </span>  <span class="Conceal">¦</span> *op <span class="Special">&lt;-</span> merge <span class="Constant">2/delete-operation</span>, save-row/before, save-column/before, top-before, cursor-row/after, cursor-column/after, top-after, deleted-cells/deleted, before-cursor/delete-from, deleted-until, <span class="Constant">0/never-coalesce</span>
diff --git a/html/lambda-to-mu.mu.html b/html/lambda-to-mu.mu.html
index b12152bd..f8b29daf 100644
--- a/html/lambda-to-mu.mu.html
+++ b/html/lambda-to-mu.mu.html
@@ -305,11 +305,11 @@ if ('onhashchange' in window) {
 <span id="L241" class="LineNr">241 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break</span> <span class="Constant">+end-pair</span>
 <span id="L242" class="LineNr">242 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
 <span id="L243" class="LineNr">243 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># still here? read next element of pair</span>
-<span id="L244" class="LineNr">244 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='065duplex_list.mu.html#L29'>next</a>:&amp;:<a href='lambda-to-mu.mu.html#L31'>cell</a>, in <span class="Special">&lt;-</span> parse in
-<span id="L245" class="LineNr">245 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> is-dot?:bool <span class="Special">&lt;-</span> <a href='lambda-to-mu.mu.html#L96'>atom-match?</a> <a href='065duplex_list.mu.html#L29'>next</a>, <span class="Constant">[.]</span>
+<span id="L244" class="LineNr">244 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='065duplex_list.mu.html#L25'>next</a>:&amp;:<a href='lambda-to-mu.mu.html#L31'>cell</a>, in <span class="Special">&lt;-</span> parse in
+<span id="L245" class="LineNr">245 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> is-dot?:bool <span class="Special">&lt;-</span> <a href='lambda-to-mu.mu.html#L96'>atom-match?</a> <a href='065duplex_list.mu.html#L25'>next</a>, <span class="Constant">[.]</span>
 <span id="L246" class="LineNr">246 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
 <span id="L247" class="LineNr">247 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> is-dot?
-<span id="L248" class="LineNr">248 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> next-curr:&amp;:<a href='lambda-to-mu.mu.html#L31'>cell</a> <span class="Special">&lt;-</span> <a href='lambda-to-mu.mu.html#L49'>new-pair</a> <a href='065duplex_list.mu.html#L29'>next</a>, <span class="Constant">0/nil</span>
+<span id="L248" class="LineNr">248 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> next-curr:&amp;:<a href='lambda-to-mu.mu.html#L31'>cell</a> <span class="Special">&lt;-</span> <a href='lambda-to-mu.mu.html#L49'>new-pair</a> <a href='065duplex_list.mu.html#L25'>next</a>, <span class="Constant">0/nil</span>
 <span id="L249" class="LineNr">249 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> <a href='lambda-to-mu.mu.html#L138'>set-rest</a> curr, next-curr
 <span id="L250" class="LineNr">250 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr <span class="Special">&lt;-</span> rest curr
 <span id="L251" class="LineNr">251 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
diff --git a/html/nqueens.mu.html b/html/nqueens.mu.html
index 8ae9d05d..441561b2 100644
--- a/html/nqueens.mu.html
+++ b/html/nqueens.mu.html
@@ -95,72 +95,71 @@ if ('onhashchange' in window) {
 <span id="L34" class="LineNr"> 34 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
 <span id="L35" class="LineNr"> 35 </span>  <span class="Conceal">¦</span> curr:<a href='nqueens.mu.html#L6'>square</a> <span class="Special">&lt;-</span> merge next-rank, next-file
 <span id="L36" class="LineNr"> 36 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
-<span id="L37" class="LineNr"> 37 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr-conflicts?:bool <span class="Special">&lt;-</span> <a href='nqueens.mu.html#L53'>conflict?</a> curr, queens
+<span id="L37" class="LineNr"> 37 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> curr-conflicts?:bool <span class="Special">&lt;-</span> <a href='nqueens.mu.html#L52'>conflict?</a> curr, queens
 <span id="L38" class="LineNr"> 38 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> curr-conflicts?
-<span id="L39" class="LineNr"> 39 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> queens <span class="Special">&lt;-</span> push curr, queens
-<span id="L40" class="LineNr"> 40 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> sub-result:num <span class="Special">&lt;-</span> <a href='nqueens.mu.html#L11'>nqueens</a> n, queens
+<span id="L39" class="LineNr"> 39 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> new-queens:&amp;:<a href='064list.mu.html#L6'>list</a>:<a href='nqueens.mu.html#L6'>square</a> <span class="Special">&lt;-</span> push curr, queens
+<span id="L40" class="LineNr"> 40 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> sub-result:num <span class="Special">&lt;-</span> <a href='nqueens.mu.html#L11'>nqueens</a> n, new-queens
 <span id="L41" class="LineNr"> 41 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> result <span class="Special">&lt;-</span> add result, sub-result
-<span id="L42" class="LineNr"> 42 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> queens <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> queens
-<span id="L43" class="LineNr"> 43 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
-<span id="L44" class="LineNr"> 44 </span>  <span class="Conceal">¦</span> next-file <span class="Special">&lt;-</span> add next-file,<span class="Constant"> 1</span>
-<span id="L45" class="LineNr"> 45 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
-<span id="L46" class="LineNr"> 46 </span>  <span class="Delimiter">}</span>
-<span id="L47" class="LineNr"> 47 </span>]
-<span id="L48" class="LineNr"> 48 </span>
-<span id="L49" class="LineNr"> 49 </span><span class="Comment"># check if putting a queen on 'curr' conflicts with any of the existing</span>
-<span id="L50" class="LineNr"> 50 </span><span class="Comment"># queens</span>
-<span id="L51" class="LineNr"> 51 </span><span class="Comment"># assumes that 'curr' is on a non-conflicting rank, and checks for conflict</span>
-<span id="L52" class="LineNr"> 52 </span><span class="Comment"># only in files and diagonals</span>
-<span id="L53" class="LineNr"> 53 </span><span class="muRecipe">def</span> <a href='nqueens.mu.html#L53'>conflict?</a> curr:<a href='nqueens.mu.html#L6'>square</a>, queens:&amp;:<a href='064list.mu.html#L6'>list</a>:<a href='nqueens.mu.html#L6'>square</a><span class="muRecipe"> -&gt; </span>result:bool [
-<span id="L54" class="LineNr"> 54 </span>  <span class="Constant">local-scope</span>
-<span id="L55" class="LineNr"> 55 </span>  <span class="Constant">load-ingredients</span>
-<span id="L56" class="LineNr"> 56 </span>  result <span class="Special">&lt;-</span> <a href='nqueens.mu.html#L61'>conflicting-file?</a> curr, queens
-<span id="L57" class="LineNr"> 57 </span>  <span class="muControl">return-if</span> result
-<span id="L58" class="LineNr"> 58 </span>  result <span class="Special">&lt;-</span> <a href='nqueens.mu.html#L77'>conflicting-diagonal?</a> curr, queens
-<span id="L59" class="LineNr"> 59 </span>]
-<span id="L60" class="LineNr"> 60 </span>
-<span id="L61" class="LineNr"> 61 </span><span class="muRecipe">def</span> <a href='nqueens.mu.html#L61'>conflicting-file?</a> curr:<a href='nqueens.mu.html#L6'>square</a>, queens:&amp;:<a href='064list.mu.html#L6'>list</a>:<a href='nqueens.mu.html#L6'>square</a><span class="muRecipe"> -&gt; </span>result:bool [
-<span id="L62" class="LineNr"> 62 </span>  <span class="Constant">local-scope</span>
-<span id="L63" class="LineNr"> 63 </span>  <span class="Constant">load-ingredients</span>
-<span id="L64" class="LineNr"> 64 </span>  curr-file:num <span class="Special">&lt;-</span> get curr, <span class="Constant">file:offset</span>
-<span id="L65" class="LineNr"> 65 </span>  <span class="Delimiter">{</span>
-<span id="L66" class="LineNr"> 66 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> queens
-<span id="L67" class="LineNr"> 67 </span>  <span class="Conceal">¦</span> q:<a href='nqueens.mu.html#L6'>square</a> <span class="Special">&lt;-</span> first queens
-<span id="L68" class="LineNr"> 68 </span>  <span class="Conceal">¦</span> qfile:num <span class="Special">&lt;-</span> get q, <span class="Constant">file:offset</span>
-<span id="L69" class="LineNr"> 69 </span>  <span class="Conceal">¦</span> file-match?:bool <span class="Special">&lt;-</span> equal curr-file, qfile
-<span id="L70" class="LineNr"> 70 </span>  <span class="Conceal">¦</span> <span class="muControl">return-if</span> file-match?, <span class="Constant">1/conflict-found</span>
-<span id="L71" class="LineNr"> 71 </span>  <span class="Conceal">¦</span> queens <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> queens
-<span id="L72" class="LineNr"> 72 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
-<span id="L73" class="LineNr"> 73 </span>  <span class="Delimiter">}</span>
-<span id="L74" class="LineNr"> 74 </span>  <span class="muControl">return</span> <span class="Constant">0/no-conflict-found</span>
-<span id="L75" class="LineNr"> 75 </span>]
-<span id="L76" class="LineNr"> 76 </span>
-<span id="L77" class="LineNr"> 77 </span><span class="muRecipe">def</span> <a href='nqueens.mu.html#L77'>conflicting-diagonal?</a> curr:<a href='nqueens.mu.html#L6'>square</a>, queens:&amp;:<a href='064list.mu.html#L6'>list</a>:<a href='nqueens.mu.html#L6'>square</a><span class="muRecipe"> -&gt; </span>result:bool [
-<span id="L78" class="LineNr"> 78 </span>  <span class="Constant">local-scope</span>
-<span id="L79" class="LineNr"> 79 </span>  <span class="Constant">load-ingredients</span>
-<span id="L80" class="LineNr"> 80 </span>  curr-rank:num <span class="Special">&lt;-</span> get curr, <span class="Constant">rank:offset</span>
-<span id="L81" class="LineNr"> 81 </span>  curr-file:num <span class="Special">&lt;-</span> get curr, <span class="Constant">file:offset</span>
-<span id="L82" class="LineNr"> 82 </span>  <span class="Delimiter">{</span>
-<span id="L83" class="LineNr"> 83 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> queens
-<span id="L84" class="LineNr"> 84 </span>  <span class="Conceal">¦</span> q:<a href='nqueens.mu.html#L6'>square</a> <span class="Special">&lt;-</span> first queens
-<span id="L85" class="LineNr"> 85 </span>  <span class="Conceal">¦</span> qrank:num <span class="Special">&lt;-</span> get q, <span class="Constant">rank:offset</span>
-<span id="L86" class="LineNr"> 86 </span>  <span class="Conceal">¦</span> qfile:num <span class="Special">&lt;-</span> get q, <span class="Constant">file:offset</span>
-<span id="L87" class="LineNr"> 87 </span>  <span class="Conceal">¦</span> rank-delta:num <span class="Special">&lt;-</span> subtract qrank, curr-rank
-<span id="L88" class="LineNr"> 88 </span>  <span class="Conceal">¦</span> file-delta:num <span class="Special">&lt;-</span> subtract qfile, curr-file
-<span id="L89" class="LineNr"> 89 </span>  <span class="Conceal">¦</span> rank-delta <span class="Special">&lt;-</span> <a href='070table.mu.html#L103'>abs</a> rank-delta
-<span id="L90" class="LineNr"> 90 </span>  <span class="Conceal">¦</span> file-delta <span class="Special">&lt;-</span> <a href='070table.mu.html#L103'>abs</a> file-delta
-<span id="L91" class="LineNr"> 91 </span>  <span class="Conceal">¦</span> diagonal-match?:bool <span class="Special">&lt;-</span> equal rank-delta, file-delta
-<span id="L92" class="LineNr"> 92 </span>  <span class="Conceal">¦</span> <span class="muControl">return-if</span> diagonal-match?, <span class="Constant">1/conflict-found</span>
-<span id="L93" class="LineNr"> 93 </span>  <span class="Conceal">¦</span> queens <span class="Special">&lt;-</span> <a href='064list.mu.html#L25'>rest</a> queens
-<span id="L94" class="LineNr"> 94 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
-<span id="L95" class="LineNr"> 95 </span>  <span class="Delimiter">}</span>
-<span id="L96" class="LineNr"> 96 </span>  <span class="muControl">return</span> <span class="Constant">0/no-conflict-found</span>
-<span id="L97" class="LineNr"> 97 </span>]
-<span id="L98" class="LineNr"> 98 </span>
-<span id="L99" class="LineNr"> 99 </span><span class="muRecipe">def</span> <a href='nqueens.mu.html#L99'>main</a> [
-<span id="L100" class="LineNr">100 </span>  <a href='nqueens.mu.html#L11'>nqueens</a><span class="Constant"> 4</span>
-<span id="L101" class="LineNr">101 </span>  $dump-trace <span class="Constant">[app]</span>
-<span id="L102" class="LineNr">102 </span>]
+<span id="L42" class="LineNr"> 42 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
+<span id="L43" class="LineNr"> 43 </span>  <span class="Conceal">¦</span> next-file <span class="Special">&lt;-</span> add next-file,<span class="Constant"> 1</span>
+<span id="L44" class="LineNr"> 44 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L45" class="LineNr"> 45 </span>  <span class="Delimiter">}</span>
+<span id="L46" class="LineNr"> 46 </span>]
+<span id="L47" class="LineNr"> 47 </span>
+<span id="L48" class="LineNr"> 48 </span><span class="Comment"># check if putting a queen on 'curr' conflicts with any of the existing</span>
+<span id="L49" class="LineNr"> 49 </span><span class="Comment"># queens</span>
+<span id="L50" class="LineNr"> 50 </span><span class="Comment"># assumes that 'curr' is on a non-conflicting rank, and checks for conflict</span>
+<span id="L51" class="LineNr"> 51 </span><span class="Comment"># only in files and diagonals</span>
+<span id="L52" class="LineNr"> 52 </span><span class="muRecipe">def</span> <a href='nqueens.mu.html#L52'>conflict?</a> curr:<a href='nqueens.mu.html#L6'>square</a>, queens:&amp;:<a href='064list.mu.html#L6'>list</a>:<a href='nqueens.mu.html#L6'>square</a><span class="muRecipe"> -&gt; </span>result:bool [
+<span id="L53" class="LineNr"> 53 </span>  <span class="Constant">local-scope</span>
+<span id="L54" class="LineNr"> 54 </span>  <span class="Constant">load-ingredients</span>
+<span id="L55" class="LineNr"> 55 </span>  result <span class="Special">&lt;-</span> <a href='nqueens.mu.html#L60'>conflicting-file?</a> curr, queens
+<span id="L56" class="LineNr"> 56 </span>  <span class="muControl">return-if</span> result
+<span id="L57" class="LineNr"> 57 </span>  result <span class="Special">&lt;-</span> <a href='nqueens.mu.html#L76'>conflicting-diagonal?</a> curr, queens
+<span id="L58" class="LineNr"> 58 </span>]
+<span id="L59" class="LineNr"> 59 </span>
+<span id="L60" class="LineNr"> 60 </span><span class="muRecipe">def</span> <a href='nqueens.mu.html#L60'>conflicting-file?</a> curr:<a href='nqueens.mu.html#L6'>square</a>, queens:&amp;:<a href='064list.mu.html#L6'>list</a>:<a href='nqueens.mu.html#L6'>square</a><span class="muRecipe"> -&gt; </span>result:bool [
+<span id="L61" class="LineNr"> 61 </span>  <span class="Constant">local-scope</span>
+<span id="L62" class="LineNr"> 62 </span>  <span class="Constant">load-ingredients</span>
+<span id="L63" class="LineNr"> 63 </span>  curr-file:num <span class="Special">&lt;-</span> get curr, <span class="Constant">file:offset</span>
+<span id="L64" class="LineNr"> 64 </span>  <span class="Delimiter">{</span>
+<span id="L65" class="LineNr"> 65 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> queens
+<span id="L66" class="LineNr"> 66 </span>  <span class="Conceal">¦</span> q:<a href='nqueens.mu.html#L6'>square</a> <span class="Special">&lt;-</span> first queens
+<span id="L67" class="LineNr"> 67 </span>  <span class="Conceal">¦</span> qfile:num <span class="Special">&lt;-</span> get q, <span class="Constant">file:offset</span>
+<span id="L68" class="LineNr"> 68 </span>  <span class="Conceal">¦</span> file-match?:bool <span class="Special">&lt;-</span> equal curr-file, qfile
+<span id="L69" class="LineNr"> 69 </span>  <span class="Conceal">¦</span> <span class="muControl">return-if</span> file-match?, <span class="Constant">1/conflict-found</span>
+<span id="L70" class="LineNr"> 70 </span>  <span class="Conceal">¦</span> queens <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> queens
+<span id="L71" class="LineNr"> 71 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L72" class="LineNr"> 72 </span>  <span class="Delimiter">}</span>
+<span id="L73" class="LineNr"> 73 </span>  <span class="muControl">return</span> <span class="Constant">0/no-conflict-found</span>
+<span id="L74" class="LineNr"> 74 </span>]
+<span id="L75" class="LineNr"> 75 </span>
+<span id="L76" class="LineNr"> 76 </span><span class="muRecipe">def</span> <a href='nqueens.mu.html#L76'>conflicting-diagonal?</a> curr:<a href='nqueens.mu.html#L6'>square</a>, queens:&amp;:<a href='064list.mu.html#L6'>list</a>:<a href='nqueens.mu.html#L6'>square</a><span class="muRecipe"> -&gt; </span>result:bool [
+<span id="L77" class="LineNr"> 77 </span>  <span class="Constant">local-scope</span>
+<span id="L78" class="LineNr"> 78 </span>  <span class="Constant">load-ingredients</span>
+<span id="L79" class="LineNr"> 79 </span>  curr-rank:num <span class="Special">&lt;-</span> get curr, <span class="Constant">rank:offset</span>
+<span id="L80" class="LineNr"> 80 </span>  curr-file:num <span class="Special">&lt;-</span> get curr, <span class="Constant">file:offset</span>
+<span id="L81" class="LineNr"> 81 </span>  <span class="Delimiter">{</span>
+<span id="L82" class="LineNr"> 82 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> queens
+<span id="L83" class="LineNr"> 83 </span>  <span class="Conceal">¦</span> q:<a href='nqueens.mu.html#L6'>square</a> <span class="Special">&lt;-</span> first queens
+<span id="L84" class="LineNr"> 84 </span>  <span class="Conceal">¦</span> qrank:num <span class="Special">&lt;-</span> get q, <span class="Constant">rank:offset</span>
+<span id="L85" class="LineNr"> 85 </span>  <span class="Conceal">¦</span> qfile:num <span class="Special">&lt;-</span> get q, <span class="Constant">file:offset</span>
+<span id="L86" class="LineNr"> 86 </span>  <span class="Conceal">¦</span> rank-delta:num <span class="Special">&lt;-</span> subtract qrank, curr-rank
+<span id="L87" class="LineNr"> 87 </span>  <span class="Conceal">¦</span> file-delta:num <span class="Special">&lt;-</span> subtract qfile, curr-file
+<span id="L88" class="LineNr"> 88 </span>  <span class="Conceal">¦</span> rank-delta <span class="Special">&lt;-</span> <a href='070table.mu.html#L103'>abs</a> rank-delta
+<span id="L89" class="LineNr"> 89 </span>  <span class="Conceal">¦</span> file-delta <span class="Special">&lt;-</span> <a href='070table.mu.html#L103'>abs</a> file-delta
+<span id="L90" class="LineNr"> 90 </span>  <span class="Conceal">¦</span> diagonal-match?:bool <span class="Special">&lt;-</span> equal rank-delta, file-delta
+<span id="L91" class="LineNr"> 91 </span>  <span class="Conceal">¦</span> <span class="muControl">return-if</span> diagonal-match?, <span class="Constant">1/conflict-found</span>
+<span id="L92" class="LineNr"> 92 </span>  <span class="Conceal">¦</span> queens <span class="Special">&lt;-</span> <a href='064list.mu.html#L24'>rest</a> queens
+<span id="L93" class="LineNr"> 93 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
+<span id="L94" class="LineNr"> 94 </span>  <span class="Delimiter">}</span>
+<span id="L95" class="LineNr"> 95 </span>  <span class="muControl">return</span> <span class="Constant">0/no-conflict-found</span>
+<span id="L96" class="LineNr"> 96 </span>]
+<span id="L97" class="LineNr"> 97 </span>
+<span id="L98" class="LineNr"> 98 </span><span class="muRecipe">def</span> <a href='nqueens.mu.html#L98'>main</a> [
+<span id="L99" class="LineNr"> 99 </span>  <a href='nqueens.mu.html#L11'>nqueens</a><span class="Constant"> 4</span>
+<span id="L100" class="LineNr">100 </span>  $dump-trace <span class="Constant">[app]</span>
+<span id="L101" class="LineNr">101 </span>]
 </pre>
 </body>
 </html>
diff --git a/nqueens.mu b/nqueens.mu
index 135668ab..e566e474 100644
--- a/nqueens.mu
+++ b/nqueens.mu
@@ -36,10 +36,9 @@ def nqueens n:num, queens:&:list:square -> result:num, queens:&:list:square [
     {
       curr-conflicts?:bool <- conflict? curr, queens
       break-if curr-conflicts?
-      queens <- push curr, queens
-      sub-result:num <- nqueens n, queens
+      new-queens:&:list:square <- push curr, queens
+      sub-result:num <- nqueens n, new-queens
       result <- add result, sub-result
-      queens <- rest queens
     }
     next-file <- add next-file, 1
     loop