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authorKartik K. Agaram <vc@akkartik.com>2016-04-25 22:27:19 -0700
committerKartik K. Agaram <vc@akkartik.com>2016-04-25 22:27:19 -0700
commit32b8fac2799ac7cec613e84a3eb9c009141b6a3a (patch)
tree11f56c1a235abf7b626ea8983fff3d2edb1fcf98 /html/028call_reply.cc.html
parent224972ee9871fcb06ee285fa5f3d9528c034d414 (diff)
downloadmu-32b8fac2799ac7cec613e84a3eb9c009141b6a3a.tar.gz
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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
+<html>
+<head>
+<meta http-equiv="content-type" content="text/html; charset=UTF-8">
+<title>Mu - 028call_reply.cc</title>
+<meta name="Generator" content="Vim/7.4">
+<meta name="plugin-version" content="vim7.4_v2">
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+<!--
+pre { white-space: pre-wrap; font-family: monospace; color: #eeeeee; background-color: #080808; }
+body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color: #080808; }
+* { font-size: 12pt; font-size: 1em; }
+.Constant { color: #00a0a0; }
+.cSpecial { color: #008000; }
+.traceContains { color: #008000; }
+.Comment { color: #9090ff; }
+.Delimiter { color: #800080; }
+.Special { color: #c00000; }
+.Identifier { color: #fcb165; }
+.Normal { color: #eeeeee; background-color: #080808; padding-bottom: 1px; }
+-->
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+
+<script type='text/javascript'>
+<!--
+
+-->
+</script>
+</head>
+<body>
+<pre id='vimCodeElement'>
+<span class="Comment">//: Calls can also generate products, using 'reply' or 'return'.</span>
+
+<span class="Delimiter">:(scenario reply)</span>
+def main [
+  <span class="Constant">1</span>:number<span class="Delimiter">,</span> <span class="Constant">2</span>:number<span class="Special"> &lt;- </span>f <span class="Constant">34</span>
+]
+def f [
+  <span class="Constant">12</span>:number<span class="Special"> &lt;- </span>next-ingredient
+  <span class="Constant">13</span>:number<span class="Special"> &lt;- </span>add <span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">12</span>:number
+  reply <span class="Constant">12</span>:number<span class="Delimiter">,</span> <span class="Constant">13</span>:number
+]
+<span class="traceContains">+mem: storing 34 in location 1</span>
+<span class="traceContains">+mem: storing 35 in location 2</span>
+
+<span class="Delimiter">:(before &quot;End Primitive Recipe Declarations&quot;)</span>
+REPLY<span class="Delimiter">,</span>
+<span class="Delimiter">:(before &quot;End Primitive Recipe Numbers&quot;)</span>
+put<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> <span class="Constant">&quot;reply&quot;</span><span class="Delimiter">,</span> REPLY<span class="Delimiter">);</span>
+put<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> <span class="Constant">&quot;return&quot;</span><span class="Delimiter">,</span> REPLY<span class="Delimiter">);</span>
+<span class="Delimiter">:(before &quot;End Primitive Recipe Checks&quot;)</span>
+<span class="Normal">case</span> REPLY: <span class="Delimiter">{</span>
+  <span class="Identifier">break</span><span class="Delimiter">;</span>  <span class="Comment">// checks will be performed by a transform below</span>
+<span class="Delimiter">}</span>
+<span class="Delimiter">:(before &quot;End Primitive Recipe Implementations&quot;)</span>
+<span class="Normal">case</span> REPLY: <span class="Delimiter">{</span>
+  <span class="Comment">// Starting Reply</span>
+  <span class="Normal">if</span> <span class="Delimiter">(</span>Trace_stream<span class="Delimiter">)</span> <span class="Delimiter">{</span>
+    trace<span class="Delimiter">(</span><span class="Constant">9999</span><span class="Delimiter">,</span> <span class="Constant">&quot;trace&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;reply: decrementing callstack depth from &quot;</span> &lt;&lt; Trace_stream<span class="Delimiter">-&gt;</span>callstack_depth &lt;&lt; end<span class="Delimiter">();</span>
+    --Trace_stream<span class="Delimiter">-&gt;</span>callstack_depth<span class="Delimiter">;</span>
+    <span class="Normal">if</span> <span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>callstack_depth &lt; <span class="Constant">0</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
+      Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span>clear<span class="Delimiter">();</span>
+      <span class="Identifier">goto</span> stop_running_current_routine<span class="Delimiter">;</span>
+    <span class="Delimiter">}</span>
+  <span class="Delimiter">}</span>
+  Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span>pop_front<span class="Delimiter">();</span>
+  <span class="Comment">// just in case 'main' returns a value, drop it for now</span>
+  <span class="Normal">if</span> <span class="Delimiter">(</span>Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span>empty<span class="Delimiter">())</span> <span class="Identifier">goto</span> stop_running_current_routine<span class="Delimiter">;</span>
+  <span class="Normal">const</span> instruction&amp; caller_instruction = current_instruction<span class="Delimiter">();</span>
+  <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">int</span> i = <span class="Constant">0</span><span class="Delimiter">;</span> i &lt; SIZE<span class="Delimiter">(</span>caller_instruction<span class="Delimiter">.</span>products<span class="Delimiter">);</span> ++i<span class="Delimiter">)</span>
+    trace<span class="Delimiter">(</span><span class="Constant">9998</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;result &quot;</span> &lt;&lt; i &lt;&lt; <span class="Constant">&quot; is &quot;</span> &lt;&lt; to_string<span class="Delimiter">(</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">))</span> &lt;&lt; end<span class="Delimiter">();</span>
+
+  <span class="Comment">// make reply products available to caller</span>
+  copy<span class="Delimiter">(</span>ingredients<span class="Delimiter">.</span>begin<span class="Delimiter">(),</span> ingredients<span class="Delimiter">.</span>end<span class="Delimiter">(),</span> inserter<span class="Delimiter">(</span>products<span class="Delimiter">,</span> products<span class="Delimiter">.</span>begin<span class="Delimiter">()));</span>
+  <span class="Comment">// End Reply</span>
+  <span class="Identifier">break</span><span class="Delimiter">;</span>  <span class="Comment">// continue to process rest of *caller* instruction</span>
+<span class="Delimiter">}</span>
+
+<span class="Comment">//: Types in reply instructions are checked ahead of time.</span>
+
+<span class="Delimiter">:(before &quot;End Checks&quot;)</span>
+Transform<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>check_types_of_reply_instructions<span class="Delimiter">);</span>
+<span class="Delimiter">:(code)</span>
+<span class="Normal">void</span> check_types_of_reply_instructions<span class="Delimiter">(</span>recipe_ordinal r<span class="Delimiter">)</span> <span class="Delimiter">{</span>
+  <span class="Normal">const</span> recipe&amp; caller = get<span class="Delimiter">(</span>Recipe<span class="Delimiter">,</span> r<span class="Delimiter">);</span>
+  trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;transform&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;--- check types of reply instructions in recipe &quot;</span> &lt;&lt; caller<span class="Delimiter">.</span>name &lt;&lt; end<span class="Delimiter">();</span>
+  <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">int</span> i = <span class="Constant">0</span><span class="Delimiter">;</span> i &lt; SIZE<span class="Delimiter">(</span>caller<span class="Delimiter">.</span>steps<span class="Delimiter">);</span> ++i<span class="Delimiter">)</span> <span class="Delimiter">{</span>
+    <span class="Normal">const</span> instruction&amp; caller_instruction = caller<span class="Delimiter">.</span>steps<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">);</span>
+    <span class="Normal">if</span> <span class="Delimiter">(</span>caller_instruction<span class="Delimiter">.</span>is_label<span class="Delimiter">)</span> <span class="Identifier">continue</span><span class="Delimiter">;</span>
+    <span class="Normal">if</span> <span class="Delimiter">(</span>caller_instruction<span class="Delimiter">.</span>products<span class="Delimiter">.</span>empty<span class="Delimiter">())</span> <span class="Identifier">continue</span><span class="Delimiter">;</span>
+    <span class="Normal">if</span> <span class="Delimiter">(</span>caller_instruction<span class="Delimiter">.</span>operation &lt; MAX_PRIMITIVE_RECIPES<span class="Delimiter">)</span> <span class="Identifier">continue</span><span class="Delimiter">;</span>
+    <span class="Normal">const</span> recipe&amp; callee = get<span class="Delimiter">(</span>Recipe<span class="Delimiter">,</span> caller_instruction<span class="Delimiter">.</span>operation<span class="Delimiter">);</span>
+    <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">int</span> i = <span class="Constant">0</span><span class="Delimiter">;</span> i &lt; SIZE<span class="Delimiter">(</span>callee<span class="Delimiter">.</span>steps<span class="Delimiter">);</span> ++i<span class="Delimiter">)</span> <span class="Delimiter">{</span>
+      <span class="Normal">const</span> instruction&amp; reply_inst = callee<span class="Delimiter">.</span>steps<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">);</span>
+      <span class="Normal">if</span> <span class="Delimiter">(</span>reply_inst<span class="Delimiter">.</span>operation != REPLY<span class="Delimiter">)</span> <span class="Identifier">continue</span><span class="Delimiter">;</span>
+      <span class="Comment">// check types with the caller</span>
+      <span class="Normal">if</span> <span class="Delimiter">(</span>SIZE<span class="Delimiter">(</span>caller_instruction<span class="Delimiter">.</span>products<span class="Delimiter">)</span> &gt; SIZE<span class="Delimiter">(</span>reply_inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">))</span> <span class="Delimiter">{</span>
+        raise &lt;&lt; maybe<span class="Delimiter">(</span>caller<span class="Delimiter">.</span>name<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;too few values replied from &quot;</span> &lt;&lt; callee<span class="Delimiter">.</span>name &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
+        <span class="Identifier">break</span><span class="Delimiter">;</span>
+      <span class="Delimiter">}</span>
+      <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">int</span> i = <span class="Constant">0</span><span class="Delimiter">;</span> i &lt; SIZE<span class="Delimiter">(</span>caller_instruction<span class="Delimiter">.</span>products<span class="Delimiter">);</span> ++i<span class="Delimiter">)</span> <span class="Delimiter">{</span>
+        reagent lhs = reply_inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">);</span>
+        reagent rhs = caller_instruction<span class="Delimiter">.</span>products<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">);</span>
+        <span class="Comment">// End Check REPLY Copy(lhs, rhs)</span>
+        <span class="Normal">if</span> <span class="Delimiter">(</span>!types_coercible<span class="Delimiter">(</span>rhs<span class="Delimiter">,</span> lhs<span class="Delimiter">))</span> <span class="Delimiter">{</span>
+          raise &lt;&lt; maybe<span class="Delimiter">(</span>callee<span class="Delimiter">.</span>name<span class="Delimiter">)</span> &lt;&lt; reply_inst<span class="Delimiter">.</span>name &lt;&lt; <span class="Constant">&quot; ingredient &quot;</span> &lt;&lt; lhs<span class="Delimiter">.</span>original_string &lt;&lt; <span class="Constant">&quot; can't be saved in &quot;</span> &lt;&lt; rhs<span class="Delimiter">.</span>original_string &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
+          raise &lt;&lt; to_string<span class="Delimiter">(</span>lhs<span class="Delimiter">.</span>type<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot; vs &quot;</span> &lt;&lt; to_string<span class="Delimiter">(</span>rhs<span class="Delimiter">.</span>type<span class="Delimiter">)</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
+          <span class="Identifier">goto</span> finish_reply_check<span class="Delimiter">;</span>
+        <span class="Delimiter">}</span>
+      <span class="Delimiter">}</span>
+      <span class="Comment">// check that any reply ingredients with /same-as-ingredient connect up</span>
+      <span class="Comment">// the corresponding ingredient and product in the caller.</span>
+      <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">int</span> i = <span class="Constant">0</span><span class="Delimiter">;</span> i &lt; SIZE<span class="Delimiter">(</span>caller_instruction<span class="Delimiter">.</span>products<span class="Delimiter">);</span> ++i<span class="Delimiter">)</span> <span class="Delimiter">{</span>
+        <span class="Normal">if</span> <span class="Delimiter">(</span>has_property<span class="Delimiter">(</span>reply_inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">),</span> <span class="Constant">&quot;same-as-ingredient&quot;</span><span class="Delimiter">))</span> <span class="Delimiter">{</span>
+          string_tree* tmp = property<span class="Delimiter">(</span>reply_inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">),</span> <span class="Constant">&quot;same-as-ingredient&quot;</span><span class="Delimiter">);</span>
+          <span class="Normal">if</span> <span class="Delimiter">(</span>!tmp || tmp<span class="Delimiter">-&gt;</span>right<span class="Delimiter">)</span> <span class="Delimiter">{</span>
+            raise &lt;&lt; maybe<span class="Delimiter">(</span>caller<span class="Delimiter">.</span>name<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;'same-as-ingredient' metadata should take exactly one value in &quot;</span> &lt;&lt; to_original_string<span class="Delimiter">(</span>reply_inst<span class="Delimiter">)</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
+            <span class="Identifier">goto</span> finish_reply_check<span class="Delimiter">;</span>
+          <span class="Delimiter">}</span>
+          <span class="Normal">int</span> ingredient_index = to_integer<span class="Delimiter">(</span>tmp<span class="Delimiter">-&gt;</span>value<span class="Delimiter">);</span>
+          <span class="Normal">if</span> <span class="Delimiter">(</span>ingredient_index &gt;= SIZE<span class="Delimiter">(</span>caller_instruction<span class="Delimiter">.</span>ingredients<span class="Delimiter">))</span> <span class="Delimiter">{</span>
+            raise &lt;&lt; maybe<span class="Delimiter">(</span>caller<span class="Delimiter">.</span>name<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;too few ingredients in '&quot;</span> &lt;&lt; to_original_string<span class="Delimiter">(</span>caller_instruction<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;'</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
+            <span class="Identifier">goto</span> finish_reply_check<span class="Delimiter">;</span>
+          <span class="Delimiter">}</span>
+          <span class="Normal">if</span> <span class="Delimiter">(</span>!is_dummy<span class="Delimiter">(</span>caller_instruction<span class="Delimiter">.</span>products<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">))</span> &amp;&amp; !is_literal<span class="Delimiter">(</span>caller_instruction<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span>ingredient_index<span class="Delimiter">))</span> &amp;&amp; caller_instruction<span class="Delimiter">.</span>products<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">).</span>name != caller_instruction<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span>ingredient_index<span class="Delimiter">).</span>name<span class="Delimiter">)</span> <span class="Delimiter">{</span>
+            raise &lt;&lt; maybe<span class="Delimiter">(</span>caller<span class="Delimiter">.</span>name<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;'&quot;</span> &lt;&lt; to_original_string<span class="Delimiter">(</span>caller_instruction<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;' should write to &quot;</span> &lt;&lt; caller_instruction<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span>ingredient_index<span class="Delimiter">).</span>original_string &lt;&lt; <span class="Constant">&quot; rather than &quot;</span> &lt;&lt; caller_instruction<span class="Delimiter">.</span>products<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">).</span>original_string &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
+          <span class="Delimiter">}</span>
+        <span class="Delimiter">}</span>
+      <span class="Delimiter">}</span>
+      <span class="Normal">finish_reply_check</span>:<span class="Delimiter">;</span>
+    <span class="Delimiter">}</span>
+  <span class="Delimiter">}</span>
+<span class="Delimiter">}</span>
+
+<span class="Delimiter">:(scenario reply_type_mismatch)</span>
+<span class="Special">% Hide_errors = true;</span>
+def main [
+  <span class="Constant">3</span>:number<span class="Special"> &lt;- </span>f <span class="Constant">2</span>
+]
+def f [
+  <span class="Constant">12</span>:number<span class="Special"> &lt;- </span>next-ingredient
+  <span class="Constant">13</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">35</span>
+  <span class="Constant">14</span>:point<span class="Special"> &lt;- </span>copy <span class="Constant">12</span>:point/<span class="Special">raw</span>
+  <span class="Identifier">return</span> <span class="Constant">14</span>:point
+]
+<span class="traceContains">+error: f: return ingredient 14:point can't be saved in 3:number</span>
+
+<span class="Comment">//: In mu we'd like to assume that any instruction doesn't modify its</span>
+<span class="Comment">//: ingredients unless they're also products. The /same-as-ingredient inside</span>
+<span class="Comment">//: the recipe's 'reply' will help catch accidental misuse of such</span>
+<span class="Comment">//: 'ingredient-products' (sometimes called in-out parameters in other languages).</span>
+
+<span class="Delimiter">:(scenario reply_same_as_ingredient)</span>
+<span class="Special">% Hide_errors = true;</span>
+def main [
+  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">0</span>
+  <span class="Constant">2</span>:number<span class="Special"> &lt;- </span>test1 <span class="Constant">1</span>:number  <span class="Comment"># call with different ingredient and product</span>
+]
+def test1 [
+  <span class="Constant">10</span>:number<span class="Special"> &lt;- </span>next-ingredient
+  <span class="Identifier">return</span> <span class="Constant">10</span>:number/same-as-ingredient:<span class="Constant">0</span>
+]
+<span class="traceContains">+error: main: '2:number &lt;- test1 1:number' should write to 1:number rather than 2:number</span>
+
+<span class="Delimiter">:(scenario reply_same_as_ingredient_dummy)</span>
+def main [
+  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">0</span>
+  _<span class="Special"> &lt;- </span>test1 <span class="Constant">1</span>:number  <span class="Comment"># call with different ingredient and product</span>
+]
+def test1 [
+  <span class="Constant">10</span>:number<span class="Special"> &lt;- </span>next-ingredient
+  <span class="Identifier">return</span> <span class="Constant">10</span>:number/same-as-ingredient:<span class="Constant">0</span>
+]
+$error: <span class="Constant">0</span>
+
+<span class="Delimiter">:(code)</span>
+string to_string<span class="Delimiter">(</span><span class="Normal">const</span> vector&lt;<span class="Normal">double</span>&gt;&amp; in<span class="Delimiter">)</span> <span class="Delimiter">{</span>
+  <span class="Normal">if</span> <span class="Delimiter">(</span>in<span class="Delimiter">.</span>empty<span class="Delimiter">())</span> <span class="Identifier">return</span> <span class="Constant">&quot;[]&quot;</span><span class="Delimiter">;</span>
+  ostringstream out<span class="Delimiter">;</span>
+  <span class="Normal">if</span> <span class="Delimiter">(</span>SIZE<span class="Delimiter">(</span>in<span class="Delimiter">)</span> == <span class="Constant">1</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
+    out &lt;&lt; no_scientific<span class="Delimiter">(</span>in<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">));</span>
+    <span class="Identifier">return</span> out<span class="Delimiter">.</span>str<span class="Delimiter">();</span>
+  <span class="Delimiter">}</span>
+  out &lt;&lt; <span class="Constant">&quot;[&quot;</span><span class="Delimiter">;</span>
+  <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">int</span> i = <span class="Constant">0</span><span class="Delimiter">;</span> i &lt; SIZE<span class="Delimiter">(</span>in<span class="Delimiter">);</span> ++i<span class="Delimiter">)</span> <span class="Delimiter">{</span>
+    <span class="Normal">if</span> <span class="Delimiter">(</span>i &gt; <span class="Constant">0</span><span class="Delimiter">)</span> out &lt;&lt; <span class="Constant">&quot;, &quot;</span><span class="Delimiter">;</span>
+    out &lt;&lt; no_scientific<span class="Delimiter">(</span>in<span class="Delimiter">.</span>at<span class="Delimiter">(</span>i<span class="Delimiter">));</span>
+  <span class="Delimiter">}</span>
+  out &lt;&lt; <span class="Constant">&quot;]&quot;</span><span class="Delimiter">;</span>
+  <span class="Identifier">return</span> out<span class="Delimiter">.</span>str<span class="Delimiter">();</span>
+<span class="Delimiter">}</span>
+
+<span class="Comment">//: Conditional reply.</span>
+
+<span class="Delimiter">:(scenario reply_if)</span>
+def main [
+  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>test1
+]
+def test1 [
+  <span class="Identifier">return</span>-<span class="Normal">if</span> <span class="Constant">0</span><span class="Delimiter">,</span> <span class="Constant">34</span>
+  <span class="Identifier">return</span> <span class="Constant">35</span>
+]
+<span class="traceContains">+mem: storing 35 in location 1</span>
+
+<span class="Delimiter">:(scenario reply_if_2)</span>
+def main [
+  <span class="Constant">1</span>:number<span class="Special"> &lt;- </span>test1
+]
+def test1 [
+  <span class="Identifier">return</span>-<span class="Normal">if</span> <span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">34</span>
+  <span class="Identifier">return</span> <span class="Constant">35</span>
+]
+<span class="traceContains">+mem: storing 34 in location 1</span>
+
+<span class="Delimiter">:(before &quot;End Rewrite Instruction(curr, recipe result)&quot;)</span>
+<span class="Comment">// rewrite `reply-if a, b, c, ...` to</span>
+<span class="Comment">//   ```</span>
+<span class="Comment">//   jump-unless a, 1:offset</span>
+<span class="Comment">//   reply b, c, ...</span>
+<span class="Comment">//   ```</span>
+<span class="Normal">if</span> <span class="Delimiter">(</span>curr<span class="Delimiter">.</span>name == <span class="Constant">&quot;reply-if&quot;</span> || curr<span class="Delimiter">.</span>name == <span class="Constant">&quot;return-if&quot;</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
+  <span class="Normal">if</span> <span class="Delimiter">(</span>curr<span class="Delimiter">.</span>products<span class="Delimiter">.</span>empty<span class="Delimiter">())</span> <span class="Delimiter">{</span>
+    curr<span class="Delimiter">.</span>operation = get<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> <span class="Constant">&quot;jump-unless&quot;</span><span class="Delimiter">);</span>
+    curr<span class="Delimiter">.</span>name = <span class="Constant">&quot;jump-unless&quot;</span><span class="Delimiter">;</span>
+    vector&lt;reagent&gt; results<span class="Delimiter">;</span>
+    copy<span class="Delimiter">(</span>++curr<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>begin<span class="Delimiter">(),</span> curr<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>end<span class="Delimiter">(),</span> inserter<span class="Delimiter">(</span>results<span class="Delimiter">,</span> results<span class="Delimiter">.</span>end<span class="Delimiter">()));</span>
+    curr<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>resize<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
+    curr<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>reagent<span class="Delimiter">(</span><span class="Constant">&quot;1:offset&quot;</span><span class="Delimiter">));</span>
+    result<span class="Delimiter">.</span>steps<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>curr<span class="Delimiter">);</span>
+    curr<span class="Delimiter">.</span>clear<span class="Delimiter">();</span>
+    curr<span class="Delimiter">.</span>operation = get<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> <span class="Constant">&quot;reply&quot;</span><span class="Delimiter">);</span>
+    curr<span class="Delimiter">.</span>name = <span class="Constant">&quot;reply&quot;</span><span class="Delimiter">;</span>
+    curr<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>swap<span class="Delimiter">(</span>results<span class="Delimiter">);</span>
+  <span class="Delimiter">}</span>
+  <span class="Normal">else</span> <span class="Delimiter">{</span>
+    raise &lt;&lt; <span class="Constant">&quot;'&quot;</span> &lt;&lt; curr<span class="Delimiter">.</span>name &lt;&lt; <span class="Constant">&quot;' never yields any products</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
+  <span class="Delimiter">}</span>
+<span class="Delimiter">}</span>
+<span class="Comment">// rewrite `reply-unless a, b, c, ...` to</span>
+<span class="Comment">//   ```</span>
+<span class="Comment">//   jump-if a, 1:offset</span>
+<span class="Comment">//   reply b, c, ...</span>
+<span class="Comment">//   ```</span>
+<span class="Normal">if</span> <span class="Delimiter">(</span>curr<span class="Delimiter">.</span>name == <span class="Constant">&quot;reply-unless&quot;</span> || curr<span class="Delimiter">.</span>name == <span class="Constant">&quot;return-unless&quot;</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
+  <span class="Normal">if</span> <span class="Delimiter">(</span>curr<span class="Delimiter">.</span>products<span class="Delimiter">.</span>empty<span class="Delimiter">())</span> <span class="Delimiter">{</span>
+    curr<span class="Delimiter">.</span>operation = get<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> <span class="Constant">&quot;jump-if&quot;</span><span class="Delimiter">);</span>
+    curr<span class="Delimiter">.</span>name = <span class="Constant">&quot;jump-if&quot;</span><span class="Delimiter">;</span>
+    vector&lt;reagent&gt; results<span class="Delimiter">;</span>
+    copy<span class="Delimiter">(</span>++curr<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>begin<span class="Delimiter">(),</span> curr<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>end<span class="Delimiter">(),</span> inserter<span class="Delimiter">(</span>results<span class="Delimiter">,</span> results<span class="Delimiter">.</span>end<span class="Delimiter">()));</span>
+    curr<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>resize<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
+    curr<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>reagent<span class="Delimiter">(</span><span class="Constant">&quot;1:offset&quot;</span><span class="Delimiter">));</span>
+    result<span class="Delimiter">.</span>steps<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>curr<span class="Delimiter">);</span>
+    curr<span class="Delimiter">.</span>clear<span class="Delimiter">();</span>
+    curr<span class="Delimiter">.</span>operation = get<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> <span class="Constant">&quot;reply&quot;</span><span class="Delimiter">);</span>
+    curr<span class="Delimiter">.</span>name = <span class="Constant">&quot;reply&quot;</span><span class="Delimiter">;</span>
+    curr<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>swap<span class="Delimiter">(</span>results<span class="Delimiter">);</span>
+  <span class="Delimiter">}</span>
+  <span class="Normal">else</span> <span class="Delimiter">{</span>
+    raise &lt;&lt; <span class="Constant">&quot;'&quot;</span> &lt;&lt; curr<span class="Delimiter">.</span>name &lt;&lt; <span class="Constant">&quot;' never yields any products</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
+  <span class="Delimiter">}</span>
+<span class="Delimiter">}</span>
+</pre>
+</body>
+</html>
+<!-- vim: set foldmethod=manual : -->