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<span class="Comment"># A doubly linked list permits bidirectional traversal.</span>
container duplex-list [
value:location
next:address:duplex-list
prev:address:duplex-list
]
<span class="Comment"># result:address:duplex-list <- push-duplex x:location, in:address:duplex-list</span>
recipe push-duplex [
<span class="Underlined">local</span>-scope
x:location<span class="Special"> <- </span>next-ingredient
<span class="Identifier">in</span>:address:duplex-list<span class="Special"> <- </span>next-ingredient
result:address:duplex-list<span class="Special"> <- </span><span class="Identifier">new</span> duplex-list:<span class="Identifier">type</span>
<span class="Identifier">val</span>:address:location<span class="Special"> <- </span>get-address *result, value:offset
*<span class="Identifier">val</span><span class="Special"> <- </span><span class="Identifier">copy</span> x
next:address:address:duplex-list<span class="Special"> <- </span>get-address *result, next:offset
*next<span class="Special"> <- </span><span class="Identifier">copy</span> <span class="Identifier">in</span>
reply-unless <span class="Identifier">in</span>, result
prev:address:address:duplex-list<span class="Special"> <- </span>get-address *<span class="Identifier">in</span>, prev:offset
*prev<span class="Special"> <- </span><span class="Identifier">copy</span> result
reply result
]
<span class="Comment"># result:location <- first-duplex in:address:duplex-list</span>
recipe first-duplex [
<span class="Underlined">local</span>-scope
<span class="Identifier">in</span>:address:duplex-list<span class="Special"> <- </span>next-ingredient
reply-unless <span class="Identifier">in</span>, 0
result:location<span class="Special"> <- </span>get *<span class="Identifier">in</span>, value:offset
reply result
]
<span class="Comment"># result:address:duplex-list <- next-duplex in:address:duplex-list</span>
recipe next-duplex [
<span class="Underlined">local</span>-scope
<span class="Identifier">in</span>:address:duplex-list<span class="Special"> <- </span>next-ingredient
reply-unless <span class="Identifier">in</span>, 0
result:address:duplex-list<span class="Special"> <- </span>get *<span class="Identifier">in</span>, next:offset
reply result
]
<span class="Comment"># result:address:duplex-list <- prev-duplex in:address:duplex-list</span>
recipe prev-duplex [
<span class="Underlined">local</span>-scope
<span class="Identifier">in</span>:address:duplex-list<span class="Special"> <- </span>next-ingredient
reply-unless <span class="Identifier">in</span>, 0
result:address:duplex-list<span class="Special"> <- </span>get *<span class="Identifier">in</span>, prev:offset
reply result
]
scenario duplex-list-handling [
run [
<span class="Comment"># reserve locations 0, 1 and 2 to check for missing null check</span>
1:number<span class="Special"> <- </span><span class="Identifier">copy</span> 34
2:number<span class="Special"> <- </span><span class="Identifier">copy</span> 35
3:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 0
3:address:duplex-list<span class="Special"> <- </span>push-duplex 3, 3:address:duplex-list
3:address:duplex-list<span class="Special"> <- </span>push-duplex 4, 3:address:duplex-list
3:address:duplex-list<span class="Special"> <- </span>push-duplex 5, 3:address:duplex-list
4:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 3:address:duplex-list
5:number<span class="Special"> <- </span>first-duplex 4:address:duplex-list
4:address:duplex-list<span class="Special"> <- </span>next-duplex 4:address:duplex-list
6:number<span class="Special"> <- </span>first-duplex 4:address:duplex-list
4:address:duplex-list<span class="Special"> <- </span>next-duplex 4:address:duplex-list
7:number<span class="Special"> <- </span>first-duplex 4:address:duplex-list
8:address:duplex-list<span class="Special"> <- </span>next-duplex 4:address:duplex-list
9:number<span class="Special"> <- </span>first-duplex 8:address:duplex-list
10:address:duplex-list<span class="Special"> <- </span>next-duplex 8:address:duplex-list
11:address:duplex-list<span class="Special"> <- </span>prev-duplex 8:address:duplex-list
4:address:duplex-list<span class="Special"> <- </span>prev-duplex 4:address:duplex-list
12:number<span class="Special"> <- </span>first-duplex 4:address:duplex-list
4:address:duplex-list<span class="Special"> <- </span>prev-duplex 4:address:duplex-list
13:number<span class="Special"> <- </span>first-duplex 4:address:duplex-list
14:boolean<span class="Special"> <- </span>equal 3:address:duplex-list, 4:address:duplex-list
]
memory-should-contain [
0<span class="Special"> <- </span>0 <span class="Comment"># no modifications to null pointers</span>
1<span class="Special"> <- </span>34
2<span class="Special"> <- </span>35
5<span class="Special"> <- </span>5 <span class="Comment"># scanning next</span>
6<span class="Special"> <- </span>4
7<span class="Special"> <- </span>3
8<span class="Special"> <- </span>0 <span class="Comment"># null</span>
9<span class="Special"> <- </span>0 <span class="Comment"># first of null</span>
10<span class="Special"> <- </span>0 <span class="Comment"># next of null</span>
11<span class="Special"> <- </span>0 <span class="Comment"># prev of null</span>
12<span class="Special"> <- </span>4 <span class="Comment"># then start scanning prev</span>
13<span class="Special"> <- </span>5
14<span class="Special"> <- </span>1 <span class="Comment"># list back at start</span>
]
]
<span class="Comment"># l:address:duplex-list <- insert-duplex x:location, in:address:duplex-list</span>
<span class="Comment"># Inserts 'x' after 'in'. Returns some pointer into the list.</span>
recipe insert-duplex [
<span class="Underlined">local</span>-scope
x:location<span class="Special"> <- </span>next-ingredient
<span class="Identifier">in</span>:address:duplex-list<span class="Special"> <- </span>next-ingredient
<span class="Identifier">new</span>-node:address:duplex-list<span class="Special"> <- </span><span class="Identifier">new</span> duplex-list:<span class="Identifier">type</span>
<span class="Identifier">val</span>:address:location<span class="Special"> <- </span>get-address *<span class="Identifier">new</span>-node, value:offset
*<span class="Identifier">val</span><span class="Special"> <- </span><span class="Identifier">copy</span> x
next-node:address:duplex-list<span class="Special"> <- </span>get *<span class="Identifier">in</span>, next:offset
<span class="Comment"># in.next = new-node</span>
y:address:address:duplex-list<span class="Special"> <- </span>get-address *<span class="Identifier">in</span>, next:offset
*y<span class="Special"> <- </span><span class="Identifier">copy</span> <span class="Identifier">new</span>-node
<span class="Comment"># new-node.prev = in</span>
y<span class="Special"> <- </span>get-address *<span class="Identifier">new</span>-node, prev:offset
*y<span class="Special"> <- </span><span class="Identifier">copy</span> <span class="Identifier">in</span>
<span class="Comment"># new-node.next = next-node</span>
y<span class="Special"> <- </span>get-address *<span class="Identifier">new</span>-node, next:offset
*y<span class="Special"> <- </span><span class="Identifier">copy</span> next-node
<span class="Comment"># if next-node is not null</span>
reply-unless next-node, <span class="Identifier">new</span>-node
<span class="Comment"># next-node.prev = new-node</span>
y<span class="Special"> <- </span>get-address *next-node, prev:offset
*y<span class="Special"> <- </span><span class="Identifier">copy</span> <span class="Identifier">new</span>-node
reply <span class="Identifier">new</span>-node <span class="Comment"># just signalling something changed; don't rely on the result</span>
]
scenario inserting-into-duplex-list [
run [
1:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 0 <span class="Comment"># 1 points to head of list</span>
1:address:duplex-list<span class="Special"> <- </span>push-duplex 3, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 4, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 5, 1:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 1:address:duplex-list <span class="Comment"># 2 points inside list</span>
2:address:duplex-list<span class="Special"> <- </span>insert-duplex 6, 2:address:duplex-list
<span class="Comment"># check structure like before</span>
2:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 1:address:duplex-list
3:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
4:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
5:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
6:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>prev-duplex 2:address:duplex-list
7:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>prev-duplex 2:address:duplex-list
8:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>prev-duplex 2:address:duplex-list
9:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
10:boolean<span class="Special"> <- </span>equal 1:address:duplex-list, 2:address:duplex-list
]
memory-should-contain [
3<span class="Special"> <- </span>5 <span class="Comment"># scanning next</span>
4<span class="Special"> <- </span>4
5<span class="Special"> <- </span>6 <span class="Comment"># inserted element</span>
6<span class="Special"> <- </span>3
7<span class="Special"> <- </span>6 <span class="Comment"># then prev</span>
8<span class="Special"> <- </span>4
9<span class="Special"> <- </span>5
10<span class="Special"> <- </span>1 <span class="Comment"># list back at start</span>
]
]
scenario inserting-at-end-of-duplex-list [
run [
1:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 0 <span class="Comment"># 1 points to head of list</span>
1:address:duplex-list<span class="Special"> <- </span>push-duplex 3, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 4, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 5, 1:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 1:address:duplex-list <span class="Comment"># 2 points inside list</span>
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list <span class="Comment"># now at end of list</span>
2:address:duplex-list<span class="Special"> <- </span>insert-duplex 6, 2:address:duplex-list
<span class="Comment"># check structure like before</span>
2:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 1:address:duplex-list
3:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
4:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
5:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
6:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>prev-duplex 2:address:duplex-list
7:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>prev-duplex 2:address:duplex-list
8:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>prev-duplex 2:address:duplex-list
9:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
10:boolean<span class="Special"> <- </span>equal 1:address:duplex-list, 2:address:duplex-list
]
memory-should-contain [
3<span class="Special"> <- </span>5 <span class="Comment"># scanning next</span>
4<span class="Special"> <- </span>4
5<span class="Special"> <- </span>3
6<span class="Special"> <- </span>6 <span class="Comment"># inserted element</span>
7<span class="Special"> <- </span>3 <span class="Comment"># then prev</span>
8<span class="Special"> <- </span>4
9<span class="Special"> <- </span>5
10<span class="Special"> <- </span>1 <span class="Comment"># list back at start</span>
]
]
scenario inserting-after-start-of-duplex-list [
run [
1:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 0 <span class="Comment"># 1 points to head of list</span>
1:address:duplex-list<span class="Special"> <- </span>push-duplex 3, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 4, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 5, 1:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>insert-duplex 6, 1:address:duplex-list
<span class="Comment"># check structure like before</span>
2:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 1:address:duplex-list
3:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
4:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
5:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
6:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>prev-duplex 2:address:duplex-list
7:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>prev-duplex 2:address:duplex-list
8:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>prev-duplex 2:address:duplex-list
9:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
10:boolean<span class="Special"> <- </span>equal 1:address:duplex-list, 2:address:duplex-list
]
memory-should-contain [
3<span class="Special"> <- </span>5 <span class="Comment"># scanning next</span>
4<span class="Special"> <- </span>6 <span class="Comment"># inserted element</span>
5<span class="Special"> <- </span>4
6<span class="Special"> <- </span>3
7<span class="Special"> <- </span>4 <span class="Comment"># then prev</span>
8<span class="Special"> <- </span>6
9<span class="Special"> <- </span>5
10<span class="Special"> <- </span>1 <span class="Comment"># list back at start</span>
]
]
<span class="Comment"># l:address:duplex-list <- remove-duplex in:address:duplex-list</span>
<span class="Comment"># Removes 'in' from its surrounding list. Returns some valid pointer into the</span>
<span class="Comment"># rest of the list.</span>
#
<span class="Comment"># Returns null if and only if list is empty. Beware: in that case any pointers</span>
<span class="Comment"># to the head are now invalid.</span>
recipe remove-duplex [
<span class="Underlined">local</span>-scope
<span class="Identifier">in</span>:address:duplex-list<span class="Special"> <- </span>next-ingredient
<span class="Comment"># if 'in' is null, return</span>
reply-unless <span class="Identifier">in</span>, <span class="Identifier">in</span>
next-node:address:duplex-list<span class="Special"> <- </span>get *<span class="Identifier">in</span>, next:offset
prev-node:address:duplex-list<span class="Special"> <- </span>get *<span class="Identifier">in</span>, prev:offset
<span class="Comment"># null in's pointers</span>
x:address:address:duplex-list<span class="Special"> <- </span>get-address *<span class="Identifier">in</span>, next:offset
*x<span class="Special"> <- </span><span class="Identifier">copy</span> 0
x<span class="Special"> <- </span>get-address *<span class="Identifier">in</span>, prev:offset
*x<span class="Special"> <- </span><span class="Identifier">copy</span> 0
{
<span class="Comment"># if next-node is not null</span>
break-unless next-node
<span class="Comment"># next-node.prev = prev-node</span>
x<span class="Special"> <- </span>get-address *next-node, prev:offset
*x<span class="Special"> <- </span><span class="Identifier">copy</span> prev-node
}
{
<span class="Comment"># if prev-node is not null</span>
break-unless prev-node
<span class="Comment"># prev-node.next = next-node</span>
x<span class="Special"> <- </span>get-address *prev-node, next:offset
*x<span class="Special"> <- </span><span class="Identifier">copy</span> next-node
reply prev-node
}
reply next-node
]
scenario removing-from-duplex-list [
run [
1:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 0 <span class="Comment"># 1 points to head of list</span>
1:address:duplex-list<span class="Special"> <- </span>push-duplex 3, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 4, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 5, 1:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 1:address:duplex-list <span class="Comment"># 2 points at second element</span>
2:address:duplex-list<span class="Special"> <- </span>remove-duplex 2:address:duplex-list
3:boolean<span class="Special"> <- </span>equal 2:address:duplex-list, 0
<span class="Comment"># check structure like before</span>
2:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 1:address:duplex-list
4:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
5:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
6:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>prev-duplex 2:address:duplex-list
7:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
8:boolean<span class="Special"> <- </span>equal 1:address:duplex-list, 2:address:duplex-list
]
memory-should-contain [
3<span class="Special"> <- </span>0 <span class="Comment"># remove returned non-null</span>
4<span class="Special"> <- </span>5 <span class="Comment"># scanning next, skipping deleted element</span>
5<span class="Special"> <- </span>3
6<span class="Special"> <- </span>0 <span class="Comment"># no more elements</span>
7<span class="Special"> <- </span>5 <span class="Comment"># prev of final element</span>
8<span class="Special"> <- </span>1 <span class="Comment"># list back at start</span>
]
]
scenario removing-from-start-of-duplex-list [
run [
1:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 0 <span class="Comment"># 1 points to head of list</span>
1:address:duplex-list<span class="Special"> <- </span>push-duplex 3, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 4, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 5, 1:address:duplex-list
<span class="Comment"># removing from head? return value matters.</span>
1:address:duplex-list<span class="Special"> <- </span>remove-duplex 1:address:duplex-list
<span class="Comment"># check structure like before</span>
2:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 1:address:duplex-list
3:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
4:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
5:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>prev-duplex 2:address:duplex-list
6:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
7:boolean<span class="Special"> <- </span>equal 1:address:duplex-list, 2:address:duplex-list
]
memory-should-contain [
3<span class="Special"> <- </span>4 <span class="Comment"># scanning next, skipping deleted element</span>
4<span class="Special"> <- </span>3
5<span class="Special"> <- </span>0 <span class="Comment"># no more elements</span>
6<span class="Special"> <- </span>4 <span class="Comment"># prev of final element</span>
7<span class="Special"> <- </span>1 <span class="Comment"># list back at start</span>
]
]
scenario removing-from-end-of-duplex-list [
run [
1:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 0 <span class="Comment"># 1 points to head of list</span>
1:address:duplex-list<span class="Special"> <- </span>push-duplex 3, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 4, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 5, 1:address:duplex-list
<span class="Comment"># delete last element</span>
2:address:duplex-list<span class="Special"> <- </span>next-duplex 1:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>remove-duplex 2:address:duplex-list
3:boolean<span class="Special"> <- </span>equal 2:address:duplex-list, 0
<span class="Comment"># check structure like before</span>
2:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 1:address:duplex-list
4:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
5:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
6:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>prev-duplex 2:address:duplex-list
7:number<span class="Special"> <- </span>first-duplex 2:address:duplex-list
8:boolean<span class="Special"> <- </span>equal 1:address:duplex-list, 2:address:duplex-list
]
memory-should-contain [
3<span class="Special"> <- </span>0 <span class="Comment"># remove returned non-null</span>
4<span class="Special"> <- </span>5 <span class="Comment"># scanning next, skipping deleted element</span>
5<span class="Special"> <- </span>4
6<span class="Special"> <- </span>0 <span class="Comment"># no more elements</span>
7<span class="Special"> <- </span>5 <span class="Comment"># prev of final element</span>
8<span class="Special"> <- </span>1 <span class="Comment"># list back at start</span>
]
]
scenario removing-from-singleton-list [
run [
1:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 0 <span class="Comment"># 1 points to singleton list</span>
1:address:duplex-list<span class="Special"> <- </span>push-duplex 3, 1:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>remove-duplex 1:address:duplex-list
3:address:duplex-list<span class="Special"> <- </span>get *1:address:duplex-list, next:offset
4:address:duplex-list<span class="Special"> <- </span>get *1:address:duplex-list, prev:offset
]
memory-should-contain [
2<span class="Special"> <- </span>0 <span class="Comment"># remove returned null</span>
3<span class="Special"> <- </span>0 <span class="Comment"># removed node is also detached</span>
4<span class="Special"> <- </span>0
]
]
<span class="Comment"># l:address:duplex-list <- remove-duplex-between start:address:duplex-list, end:address:duplex-list</span>
<span class="Comment"># Remove values between 'start' and 'end' (both exclusive). Returns some valid</span>
<span class="Comment"># pointer into the rest of the list.</span>
<span class="Comment"># Also clear pointers back out from start/end for hygiene.</span>
recipe remove-duplex-between [
<span class="Underlined">local</span>-scope
start:address:duplex-list<span class="Special"> <- </span>next-ingredient
end:address:duplex-list<span class="Special"> <- </span>next-ingredient
reply-unless start, start
<span class="Comment"># start->next->prev = 0</span>
<span class="Comment"># start->next = end</span>
next:address:address:duplex-list<span class="Special"> <- </span>get-address *start, next:offset
nothing-to-<span class="Identifier">delete</span>?:boolean<span class="Special"> <- </span>equal *next, end
reply-if nothing-to-<span class="Identifier">delete</span>?, start
prev:address:address:duplex-list<span class="Special"> <- </span>get-address **next, prev:offset
*prev<span class="Special"> <- </span><span class="Identifier">copy</span> 0
*next<span class="Special"> <- </span><span class="Identifier">copy</span> end
reply-unless end, start
<span class="Comment"># end->prev->next = 0</span>
<span class="Comment"># end->prev = start</span>
prev<span class="Special"> <- </span>get-address *end, prev:offset
next<span class="Special"> <- </span>get-address **prev, next:offset
*next<span class="Special"> <- </span><span class="Identifier">copy</span> 0
*prev<span class="Special"> <- </span><span class="Identifier">copy</span> start
reply start
]
scenario remove-range [
<span class="Comment"># construct a duplex list with six elements [13, 14, 15, 16, 17, 18]</span>
1:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 0 <span class="Comment"># 1 points to singleton list</span>
1:address:duplex-list<span class="Special"> <- </span>push-duplex 18, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 17, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 16, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 15, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 14, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 13, 1:address:duplex-list
run [
<span class="Comment"># delete 16 onwards</span>
<span class="Comment"># first pointer: to the third element</span>
2:address:duplex-list<span class="Special"> <- </span>next-duplex 1:address:duplex-list
2:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
remove-duplex-between 2:address:duplex-list, 0
<span class="Comment"># now check the list</span>
4:number<span class="Special"> <- </span>get *1:address:duplex-list, value:offset
5:address:duplex-list<span class="Special"> <- </span>next-duplex 1:address:duplex-list
6:number<span class="Special"> <- </span>get *5:address:duplex-list, value:offset
7:address:duplex-list<span class="Special"> <- </span>next-duplex 5:address:duplex-list
8:number<span class="Special"> <- </span>get *7:address:duplex-list, value:offset
9:address:duplex-list<span class="Special"> <- </span>next-duplex 7:address:duplex-list
]
memory-should-contain [
4<span class="Special"> <- </span>13
6<span class="Special"> <- </span>14
8<span class="Special"> <- </span>15
9<span class="Special"> <- </span>0
]
]
scenario remove-range-to-end [
<span class="Comment"># construct a duplex list with six elements [13, 14, 15, 16, 17, 18]</span>
1:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 0 <span class="Comment"># 1 points to singleton list</span>
1:address:duplex-list<span class="Special"> <- </span>push-duplex 18, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 17, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 16, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 15, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 14, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 13, 1:address:duplex-list
run [
<span class="Comment"># delete 15, 16 and 17</span>
<span class="Comment"># first pointer: to the third element</span>
2:address:duplex-list<span class="Special"> <- </span>next-duplex 1:address:duplex-list
<span class="Comment"># second pointer: to the fifth element</span>
3:address:duplex-list<span class="Special"> <- </span>next-duplex 2:address:duplex-list
3:address:duplex-list<span class="Special"> <- </span>next-duplex 3:address:duplex-list
3:address:duplex-list<span class="Special"> <- </span>next-duplex 3:address:duplex-list
3:address:duplex-list<span class="Special"> <- </span>next-duplex 3:address:duplex-list
remove-duplex-between 2:address:duplex-list, 3:address:duplex-list
<span class="Comment"># now check the list</span>
4:number<span class="Special"> <- </span>get *1:address:duplex-list, value:offset
5:address:duplex-list<span class="Special"> <- </span>next-duplex 1:address:duplex-list
6:number<span class="Special"> <- </span>get *5:address:duplex-list, value:offset
7:address:duplex-list<span class="Special"> <- </span>next-duplex 5:address:duplex-list
8:number<span class="Special"> <- </span>get *7:address:duplex-list, value:offset
9:address:duplex-list<span class="Special"> <- </span>next-duplex 7:address:duplex-list
]
memory-should-contain [
4<span class="Special"> <- </span>13
6<span class="Special"> <- </span>14
8<span class="Special"> <- </span>18
9<span class="Special"> <- </span>0
]
]
scenario remove-range-empty [
<span class="Comment"># construct a duplex list with six elements [13, 14, 15, 16, 17, 18]</span>
1:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> 0 <span class="Comment"># 1 points to singleton list</span>
1:address:duplex-list<span class="Special"> <- </span>push-duplex 14, 1:address:duplex-list
1:address:duplex-list<span class="Special"> <- </span>push-duplex 13, 1:address:duplex-list
run [
<span class="Comment"># delete 16 onwards</span>
<span class="Comment"># first pointer: to the third element</span>
2:address:duplex-list<span class="Special"> <- </span>next-duplex 1:address:duplex-list
remove-duplex-between 1:address:duplex-list, 2:address:duplex-list
<span class="Comment"># now check the list</span>
4:number<span class="Special"> <- </span>get *1:address:duplex-list, value:offset
5:address:duplex-list<span class="Special"> <- </span>next-duplex 1:address:duplex-list
6:number<span class="Special"> <- </span>get *5:address:duplex-list, value:offset
7:address:duplex-list<span class="Special"> <- </span>next-duplex 5:address:duplex-list
]
memory-should-contain [
4<span class="Special"> <- </span>13
6<span class="Special"> <- </span>14
7<span class="Special"> <- </span>0
]
]
<span class="Comment"># l:address:duplex-list <- insert-duplex-range in:address:duplex-list, new:address:duplex-list</span>
<span class="Comment"># Inserts list beginning at 'new' after 'in'. Returns some pointer into the list.</span>
recipe insert-duplex-range [
<span class="Underlined">local</span>-scope
<span class="Identifier">in</span>:address:duplex-list<span class="Special"> <- </span>next-ingredient
start:address:duplex-list<span class="Special"> <- </span>next-ingredient
reply-unless <span class="Identifier">in</span>, <span class="Identifier">in</span>
reply-unless start, <span class="Identifier">in</span>
end:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> start
{
next:address:duplex-list<span class="Special"> <- </span>next-duplex end
break-unless next
end<span class="Special"> <- </span><span class="Identifier">copy</span> next
loop
}
next:address:duplex-list<span class="Special"> <- </span>next-duplex <span class="Identifier">in</span>
dest:address:address:duplex-list<span class="Special"> <- </span>get-address *end, next:offset
*dest<span class="Special"> <- </span><span class="Identifier">copy</span> next
{
break-unless next
dest<span class="Special"> <- </span>get-address *next, prev:offset
*dest<span class="Special"> <- </span><span class="Identifier">copy</span> end
}
dest<span class="Special"> <- </span>get-address *<span class="Identifier">in</span>, next:offset
*dest<span class="Special"> <- </span><span class="Identifier">copy</span> start
dest<span class="Special"> <- </span>get-address *start, prev:offset
*dest<span class="Special"> <- </span><span class="Identifier">copy</span> <span class="Identifier">in</span>
reply <span class="Identifier">in</span>
]
recipe <span class="Identifier">append</span>-duplex [
<span class="Underlined">local</span>-scope
<span class="Identifier">in</span>:address:duplex-list<span class="Special"> <- </span>next-ingredient
<span class="Identifier">new</span>:address:duplex-list<span class="Special"> <- </span>next-ingredient
<span class="Identifier">last</span>:address:duplex-list<span class="Special"> <- </span><span class="Identifier">last</span>-duplex <span class="Identifier">in</span>
dest:address:address:duplex-list<span class="Special"> <- </span>get-address *<span class="Identifier">last</span>, next:offset
*dest<span class="Special"> <- </span><span class="Identifier">copy</span> <span class="Identifier">new</span>
reply-unless <span class="Identifier">new</span>, <span class="Identifier">in</span>/same-as-ingredient:0
dest<span class="Special"> <- </span>get-address *<span class="Identifier">new</span>, prev:offset
*dest<span class="Special"> <- </span><span class="Identifier">copy</span> <span class="Identifier">last</span>
reply <span class="Identifier">in</span>/same-as-ingredient:0
]
recipe <span class="Identifier">last</span>-duplex [
<span class="Underlined">local</span>-scope
<span class="Identifier">in</span>:address:duplex-list<span class="Special"> <- </span>next-ingredient
result:address:duplex-list<span class="Special"> <- </span><span class="Identifier">copy</span> <span class="Identifier">in</span>
{
next:address:duplex-list<span class="Special"> <- </span>next-duplex result
break-unless next
result<span class="Special"> <- </span><span class="Identifier">copy</span> next
loop
}
reply result
]
<span class="Comment"># helper for debugging</span>
recipe dump-duplex-from [
<span class="Underlined">local</span>-scope
x:address:duplex-list<span class="Special"> <- </span>next-ingredient
$<span class="Identifier">print</span> x, [: ]
{
break-unless x
c:character<span class="Special"> <- </span>get *x, value:offset
$<span class="Identifier">print</span> c, [ ]
x<span class="Special"> <- </span>next-duplex x
{
<span class="Identifier">is</span>-newline?:boolean<span class="Special"> <- </span>equal c, 10/newline
break-unless <span class="Identifier">is</span>-newline?
$<span class="Identifier">print</span> 10/newline
$<span class="Identifier">print</span> x, [: ]
}
loop
}
$<span class="Identifier">print</span> 10/newline, [---], 10/newline
]
</pre>
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