about summary refs log tree commit diff stats
path: root/html/076continuation.cc.html
blob: db9ae8c5ca03619387308a0d3a2e3b6712ff2e28 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
<!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 - 076continuation.cc</title>
<meta name="Generator" content="Vim/7.4">
<meta name="plugin-version" content="vim7.4_v2">
<meta name="syntax" content="cpp">
<meta name="settings" content="number_lines,use_css,pre_wrap,no_foldcolumn,expand_tabs,line_ids,prevent_copy=">
<meta name="colorscheme" content="minimal">
<style type="text/css">
<!--
pre { white-space: pre-wrap; font-family: monospace; color: #aaaaaa; background-color: #080808; }
body { font-size: 12pt; font-family: monospace; color: #aaaaaa; background-color: #080808; }
a { color:#eeeeee; text-decoration: none; }
a:hover { text-decoration: underline; }
* { font-size: 12pt; font-size: 1em; }
.Constant { color: #00a0a0; }
.muRecipe { color: #ff8700; }
.Special { color: #c00000; }
.Conceal { color: #4e4e4e; }
.traceAbsent { color: #c00000; }
.Comment { color: #9090ff; }
.Comment a { color:#0000ee; text-decoration:underline; }
.Delimiter { color: #800080; }
.LineNr { color: #444444; }
.Identifier { color: #c0a020; }
.Normal { color: #aaaaaa; background-color: #080808; padding-bottom: 1px; }
.cSpecial { color: #008000; }
.traceContains { color: #008000; }
-->
</style>

<script type='text/javascript'>
<!--

/* function to open any folds containing a jumped-to line before jumping to it */
function JumpToLine()
{
  var lineNum;
  lineNum = window.location.hash;
  lineNum = lineNum.substr(1); /* strip off '#' */

  if (lineNum.indexOf('L') == -1) {
    lineNum = 'L'+lineNum;
  }
  lineElem = document.getElementById(lineNum);
  /* Always jump to new location even if the line was hidden inside a fold, or
   * we corrected the raw number to a line ID.
   */
  if (lineElem) {
    lineElem.scrollIntoView(true);
  }
  return true;
}
if ('onhashchange' in window) {
  window.onhashchange = JumpToLine;
}

-->
</script>
</head>
<body onload='JumpToLine();'>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr">  1 </span><span class="Comment">//: Continuations are a powerful primitive for constructing advanced kinds of</span>
<span id="L2" class="LineNr">  2 </span><span class="Comment">//: control *policies* like back-tracking.</span>
<span id="L3" class="LineNr">  3 </span><span class="Comment">//:</span>
<span id="L4" class="LineNr">  4 </span><span class="Comment">//: In Mu, continuations are first-class and delimited, and are constructed</span>
<span id="L5" class="LineNr">  5 </span><span class="Comment">//: out of two primitives:</span>
<span id="L6" class="LineNr">  6 </span><span class="Comment">//:</span>
<span id="L7" class="LineNr">  7 </span><span class="Comment">//:  * 'call-with-continuation-mark' marks the top of the call stack and then</span>
<span id="L8" class="LineNr">  8 </span><span class="Comment">//:    calls the provided function.</span>
<span id="L9" class="LineNr">  9 </span><span class="Comment">//:  * 'return-continuation-until-mark' copies the top of the stack</span>
<span id="L10" class="LineNr"> 10 </span><span class="Comment">//:    until the mark, and returns it as the result of</span>
<span id="L11" class="LineNr"> 11 </span><span class="Comment">//:    call-with-continuation-mark (which might be a distant ancestor on the call</span>
<span id="L12" class="LineNr"> 12 </span><span class="Comment">//:    stack; intervening calls don't return)</span>
<span id="L13" class="LineNr"> 13 </span><span class="Comment">//:</span>
<span id="L14" class="LineNr"> 14 </span><span class="Comment">//: The resulting slice of the stack can now be called just like a regular</span>
<span id="L15" class="LineNr"> 15 </span><span class="Comment">//: function.</span>
<span id="L16" class="LineNr"> 16 </span>
<span id="L17" class="LineNr"> 17 </span><span class="Delimiter">:(before &quot;End Mu Types Initialization&quot;)</span>
<span id="L18" class="LineNr"> 18 </span><a href='010vm.cc.html#L123'>type_ordinal</a> continuation = Type_ordinal[<span class="Constant">&quot;continuation&quot;</span>] = Next_type_ordinal++<span class="Delimiter">;</span>
<span id="L19" class="LineNr"> 19 </span>Type[continuation]<span class="Delimiter">.</span>name = <span class="Constant">&quot;continuation&quot;</span><span class="Delimiter">;</span>
<span id="L20" class="LineNr"> 20 </span>
<span id="L21" class="LineNr"> 21 </span><span class="Comment">//: A continuation can be called like a recipe.</span>
<span id="L22" class="LineNr"> 22 </span><span class="Delimiter">:(before &quot;End <a href='072recipe.cc.html#L277'>is_mu_recipe</a> Atom Cases(r)&quot;)</span>
<span id="L23" class="LineNr"> 23 </span><span class="Normal">if</span> <span class="Delimiter">(</span>r<span class="Delimiter">.</span>type<span class="Delimiter">-&gt;</span>name == <span class="Constant">&quot;continuation&quot;</span><span class="Delimiter">)</span> <span class="Identifier">return</span> <span class="Constant">true</span><span class="Delimiter">;</span>
<span id="L24" class="LineNr"> 24 </span>
<span id="L25" class="LineNr"> 25 </span><span class="Comment">//: However, it can't be type-checked like most recipes. Pretend it's like a</span>
<span id="L26" class="LineNr"> 26 </span><span class="Comment">//: header-less recipe.</span>
<span id="L27" class="LineNr"> 27 </span><span class="Delimiter">:(after &quot;Begin Reagent-&gt;Recipe(r, recipe_header)&quot;)</span>
<span id="L28" class="LineNr"> 28 </span><span class="Normal">if</span> <span class="Delimiter">(</span>r<span class="Delimiter">.</span>type<span class="Delimiter">-&gt;</span>atom &amp;&amp; r<span class="Delimiter">.</span>type<span class="Delimiter">-&gt;</span>name == <span class="Constant">&quot;continuation&quot;</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L29" class="LineNr"> 29 </span>  result_header<span class="Delimiter">.</span>has_header = <span class="Constant">false</span><span class="Delimiter">;</span>
<span id="L30" class="LineNr"> 30 </span>  <span class="Identifier">return</span> result_header<span class="Delimiter">;</span>
<span id="L31" class="LineNr"> 31 </span><span class="Delimiter">}</span>
<span id="L32" class="LineNr"> 32 </span>
<span id="L33" class="LineNr"> 33 </span><span class="Delimiter">:(scenario delimited_continuation)</span>
<span id="L34" class="LineNr"> 34 </span><span class="muRecipe"><a href='010vm.cc.html#L19'>recipe</a></span> <a href='000organization.cc.html#L113'>main</a> [
<span id="L35" class="LineNr"> 35 </span>  <span class="Constant">1</span>:continuation<span class="Special"> &lt;- </span>call-with-continuation-mark f<span class="Delimiter">,</span> <span class="Constant">77</span>  <span class="Comment"># 77 is an argument to f</span>
<span id="L36" class="LineNr"> 36 </span>  <span class="Constant">2</span>:number<span class="Special"> &lt;- </span>copy <span class="Constant">5</span>
<span id="L37" class="LineNr"> 37 </span>  <span class="Delimiter">{</span>
<span id="L38" class="LineNr"> 38 </span>  <span class="Conceal">¦</span> <span class="Constant">2</span>:number<span class="Special"> &lt;- </span>call <span class="Constant">1</span>:continuation<span class="Delimiter">,</span> <span class="Constant">2</span>:number  <span class="Comment"># 2 is an argument to g, the 'top' of the continuation</span>
<span id="L39" class="LineNr"> 39 </span>  <span class="Conceal">¦</span> <span class="Constant">3</span>:boolean<span class="Special"> &lt;- </span>greater-<span class="Normal">or</span>-equal <span class="Constant">2</span>:number<span class="Delimiter">,</span> <span class="Constant">8</span>
<span id="L40" class="LineNr"> 40 </span>  <span class="Conceal">¦</span> <span class="Identifier">break</span>-<span class="Normal">if</span> <span class="Constant">3</span>:boolean
<span id="L41" class="LineNr"> 41 </span>  <span class="Conceal">¦</span> loop
<span id="L42" class="LineNr"> 42 </span>  <span class="Delimiter">}</span>
<span id="L43" class="LineNr"> 43 </span>]
<span id="L44" class="LineNr"> 44 </span><span class="muRecipe"><a href='010vm.cc.html#L19'>recipe</a></span> f [
<span id="L45" class="LineNr"> 45 </span>  <span class="Constant">11</span>:number<span class="Special"> &lt;- </span>next-ingredient
<span id="L46" class="LineNr"> 46 </span>  <span class="Constant">12</span>:number<span class="Special"> &lt;- </span>g <span class="Constant">11</span>:number
<span id="L47" class="LineNr"> 47 </span>  <span class="Identifier">return</span> <span class="Constant">12</span>:number
<span id="L48" class="LineNr"> 48 </span>]
<span id="L49" class="LineNr"> 49 </span><span class="muRecipe"><a href='010vm.cc.html#L19'>recipe</a></span> g [
<span id="L50" class="LineNr"> 50 </span>  <span class="Constant">21</span>:number<span class="Special"> &lt;- </span>next-ingredient
<span id="L51" class="LineNr"> 51 </span>  rewind-ingredients
<span id="L52" class="LineNr"> 52 </span>  <span class="Identifier">return</span>-continuation-until-mark
<span id="L53" class="LineNr"> 53 </span>  <span class="Comment"># calls of the continuation start from here</span>
<span id="L54" class="LineNr"> 54 </span>  <span class="Constant">22</span>:number<span class="Special"> &lt;- </span>next-ingredient
<span id="L55" class="LineNr"> 55 </span>  <span class="Constant">23</span>:number<span class="Special"> &lt;- </span>add <span class="Constant">22</span>:number<span class="Delimiter">,</span> <span class="Constant">1</span>
<span id="L56" class="LineNr"> 56 </span>  <span class="Identifier">return</span> <span class="Constant">23</span>:number
<span id="L57" class="LineNr"> 57 </span>]
<span id="L58" class="LineNr"> 58 </span><span class="Comment"># first call of 'g' executes the part before return-continuation-until-mark</span>
<span id="L59" class="LineNr"> 59 </span><span class="traceContains">+mem: storing 77 in location 21</span>
<span id="L60" class="LineNr"> 60 </span><span class="traceContains">+run: {2: &quot;number&quot;} &lt;- copy {5: &quot;literal&quot;}</span>
<span id="L61" class="LineNr"> 61 </span><span class="traceContains">+mem: storing 5 in location 2</span>
<span id="L62" class="LineNr"> 62 </span><span class="Comment"># calls of the continuation execute the part after return-continuation-until-mark</span>
<span id="L63" class="LineNr"> 63 </span><span class="traceContains">+run: {2: &quot;number&quot;} &lt;- call {1: &quot;continuation&quot;}, {2: &quot;number&quot;}</span>
<span id="L64" class="LineNr"> 64 </span><span class="traceContains">+mem: storing 5 in location 22</span>
<span id="L65" class="LineNr"> 65 </span><span class="traceContains">+mem: storing 6 in location 2</span>
<span id="L66" class="LineNr"> 66 </span><span class="traceContains">+run: {2: &quot;number&quot;} &lt;- call {1: &quot;continuation&quot;}, {2: &quot;number&quot;}</span>
<span id="L67" class="LineNr"> 67 </span><span class="traceContains">+mem: storing 6 in location 22</span>
<span id="L68" class="LineNr"> 68 </span><span class="traceContains">+mem: storing 7 in location 2</span>
<span id="L69" class="LineNr"> 69 </span><span class="traceContains">+run: {2: &quot;number&quot;} &lt;- call {1: &quot;continuation&quot;}, {2: &quot;number&quot;}</span>
<span id="L70" class="LineNr"> 70 </span><span class="traceContains">+mem: storing 7 in location 22</span>
<span id="L71" class="LineNr"> 71 </span><span class="traceContains">+mem: storing 8 in location 2</span>
<span id="L72" class="LineNr"> 72 </span><span class="Comment"># first call of 'g' does not execute the part after return-continuation-until-mark</span>
<span id="L73" class="LineNr"> 73 </span><span class="traceAbsent">-mem: storing 77 in location 22</span>
<span id="L74" class="LineNr"> 74 </span><span class="Comment"># calls of the continuation don't execute the part before return-continuation-until-mark</span>
<span id="L75" class="LineNr"> 75 </span><span class="traceAbsent">-mem: storing 5 in location 21</span>
<span id="L76" class="LineNr"> 76 </span><span class="traceAbsent">-mem: storing 6 in location 21</span>
<span id="L77" class="LineNr"> 77 </span><span class="traceAbsent">-mem: storing 7 in location 21</span>
<span id="L78" class="LineNr"> 78 </span><span class="Comment"># termination</span>
<span id="L79" class="LineNr"> 79 </span><span class="traceAbsent">-mem: storing 9 in location 2</span>
<span id="L80" class="LineNr"> 80 </span>
<span id="L81" class="LineNr"> 81 </span><span class="Delimiter">:(before &quot;End call Fields&quot;)</span>
<span id="L82" class="LineNr"> 82 </span><span class="Normal">bool</span> is_base_of_continuation<span class="Delimiter">;</span>
<span id="L83" class="LineNr"> 83 </span><span class="Delimiter">:(before &quot;End call Constructor&quot;)</span>
<span id="L84" class="LineNr"> 84 </span>is_base_of_continuation = <span class="Constant">false</span><span class="Delimiter">;</span>
<span id="L85" class="LineNr"> 85 </span>
<span id="L86" class="LineNr"> 86 </span><span class="Delimiter">:(before &quot;End Primitive Recipe Declarations&quot;)</span>
<span id="L87" class="LineNr"> 87 </span>CALL_WITH_CONTINUATION_MARK<span class="Delimiter">,</span>
<span id="L88" class="LineNr"> 88 </span><span class="Delimiter">:(before &quot;End Primitive Recipe Numbers&quot;)</span>
<span id="L89" class="LineNr"> 89 </span>Recipe_ordinal[<span class="Constant">&quot;call-with-continuation-mark&quot;</span>] = CALL_WITH_CONTINUATION_MARK<span class="Delimiter">;</span>
<span id="L90" class="LineNr"> 90 </span><span class="Delimiter">:(before &quot;End Primitive Recipe Checks&quot;)</span>
<span id="L91" class="LineNr"> 91 </span><span class="Normal">case</span> CALL_WITH_CONTINUATION_MARK: <span class="Delimiter">{</span>
<span id="L92" class="LineNr"> 92 </span>  <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L93" class="LineNr"> 93 </span><span class="Delimiter">}</span>
<span id="L94" class="LineNr"> 94 </span><span class="Delimiter">:(before &quot;End Primitive Recipe Implementations&quot;)</span>
<span id="L95" class="LineNr"> 95 </span><span class="Normal">case</span> CALL_WITH_CONTINUATION_MARK: <span class="Delimiter">{</span>
<span id="L96" class="LineNr"> 96 </span>  <span class="Comment">// like call, but mark the current call as a 'base of continuation' call</span>
<span id="L97" class="LineNr"> 97 </span>  <span class="Comment">// before pushing the next one on it</span>
<span id="L98" class="LineNr"> 98 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>Trace_stream<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L99" class="LineNr"> 99 </span>  <span class="Conceal">¦</span> ++Trace_stream<span class="Delimiter">-&gt;</span>callstack_depth<span class="Delimiter">;</span>
<span id="L100" class="LineNr">100 </span>  <span class="Conceal">¦</span> <a href='003trace.cc.html#L161'>trace</a><span class="Delimiter">(</span><span class="Constant">&quot;trace&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;delimited continuation; incrementing callstack depth to &quot;</span> &lt;&lt; Trace_stream<span class="Delimiter">-&gt;</span>callstack_depth &lt;&lt; <a href='003trace.cc.html#L197'>end</a><span class="Delimiter">();</span>
<span id="L101" class="LineNr">101 </span>  <span class="Conceal">¦</span> assert<span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>callstack_depth &lt; <span class="Constant">9000</span><span class="Delimiter">);</span>  <span class="Comment">// 9998-101 plus cushion</span>
<span id="L102" class="LineNr">102 </span>  <span class="Delimiter">}</span>
<span id="L103" class="LineNr">103 </span>  <span class="Normal">const</span> instruction&amp; caller_instruction = <a href='026call.cc.html#L85'>current_instruction</a><span class="Delimiter">();</span>
<span id="L104" class="LineNr">104 </span>  Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span>front<span class="Delimiter">().</span>is_base_of_continuation = <span class="Constant">true</span><span class="Delimiter">;</span>
<span id="L105" class="LineNr">105 </span>  Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span>push_front<span class="Delimiter">(</span>call<span class="Delimiter">(</span>Recipe_ordinal[current_instruction<span class="Delimiter">().</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>name]<span class="Delimiter">));</span>
<span id="L106" class="LineNr">106 </span>  ingredients<span class="Delimiter">.</span>erase<span class="Delimiter">(</span>ingredients<span class="Delimiter">.</span>begin<span class="Delimiter">());</span>  <span class="Comment">// drop the callee</span>
<span id="L107" class="LineNr">107 </span>  finish_call_housekeeping<span class="Delimiter">(</span>caller_instruction<span class="Delimiter">,</span> ingredients<span class="Delimiter">);</span>
<span id="L108" class="LineNr">108 </span>  <span class="Identifier">continue</span><span class="Delimiter">;</span>
<span id="L109" class="LineNr">109 </span><span class="Delimiter">}</span>
<span id="L110" class="LineNr">110 </span>
<span id="L111" class="LineNr">111 </span><span class="Comment">//: save the slice of current call stack until the 'call-with-continuation-mark'</span>
<span id="L112" class="LineNr">112 </span><span class="Comment">//: call, and return it as the result.</span>
<span id="L113" class="LineNr">113 </span><span class="Comment">//: todo: implement delimited continuations in Mu's memory</span>
<span id="L114" class="LineNr">114 </span><span class="Delimiter">:(before &quot;End Globals&quot;)</span>
<span id="L115" class="LineNr">115 </span>map&lt;<span class="Normal">long</span> <span class="Normal">long</span> <span class="Normal">int</span><span class="Delimiter">,</span> call_stack&gt; Delimited_continuation<span class="Delimiter">;</span>
<span id="L116" class="LineNr">116 </span><span class="Normal">long</span> <span class="Normal">long</span> <span class="Normal">int</span> Next_delimited_continuation_id = <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L117" class="LineNr">117 </span><span class="Delimiter">:(before &quot;End Reset&quot;)</span>
<span id="L118" class="LineNr">118 </span>Delimited_continuation<span class="Delimiter">.</span><a href='050scenario.cc.html#L60'>clear</a><span class="Delimiter">();</span>
<span id="L119" class="LineNr">119 </span>Next_delimited_continuation_id = <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L120" class="LineNr">120 </span>
<span id="L121" class="LineNr">121 </span><span class="Delimiter">:(before &quot;End Primitive Recipe Declarations&quot;)</span>
<span id="L122" class="LineNr">122 </span>RETURN_CONTINUATION_UNTIL_MARK<span class="Delimiter">,</span>
<span id="L123" class="LineNr">123 </span><span class="Delimiter">:(before &quot;End Primitive Recipe Numbers&quot;)</span>
<span id="L124" class="LineNr">124 </span>Recipe_ordinal[<span class="Constant">&quot;return-continuation-until-mark&quot;</span>] = RETURN_CONTINUATION_UNTIL_MARK<span class="Delimiter">;</span>
<span id="L125" class="LineNr">125 </span><span class="Delimiter">:(before &quot;End Primitive Recipe Checks&quot;)</span>
<span id="L126" class="LineNr">126 </span><span class="Normal">case</span> RETURN_CONTINUATION_UNTIL_MARK: <span class="Delimiter">{</span>
<span id="L127" class="LineNr">127 </span>  <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L128" class="LineNr">128 </span><span class="Delimiter">}</span>
<span id="L129" class="LineNr">129 </span><span class="Delimiter">:(before &quot;End Primitive Recipe Implementations&quot;)</span>
<span id="L130" class="LineNr">130 </span><span class="Normal">case</span> RETURN_CONTINUATION_UNTIL_MARK: <span class="Delimiter">{</span>
<span id="L131" class="LineNr">131 </span>  <span class="Comment">// first clear any existing ingredients, to isolate the creation of the</span>
<span id="L132" class="LineNr">132 </span>  <span class="Comment">// continuation from its calls</span>
<span id="L133" class="LineNr">133 </span>  Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span>front<span class="Delimiter">().</span>ingredient_atoms<span class="Delimiter">.</span><a href='050scenario.cc.html#L60'>clear</a><span class="Delimiter">();</span>
<span id="L134" class="LineNr">134 </span>  Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span>front<span class="Delimiter">().</span>next_ingredient_to_process = <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L135" class="LineNr">135 </span>  <span class="Comment">// copy the current call stack until the most recent marked call</span>
<span id="L136" class="LineNr">136 </span>  call_stack::iterator find_base_of_continuation<span class="Delimiter">(</span>call_stack&amp; c<span class="Delimiter">);</span>  <span class="Comment">// manual prototype containing '::'</span>
<span id="L137" class="LineNr">137 </span>  call_stack::iterator base = find_base_of_continuation<span class="Delimiter">(</span>Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">);</span>
<span id="L138" class="LineNr">138 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>base == Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span><a href='003trace.cc.html#L197'>end</a><span class="Delimiter">())</span> <span class="Delimiter">{</span>
<span id="L139" class="LineNr">139 </span>  <span class="Conceal">¦</span> <a href='003trace.cc.html#L168'>raise</a> &lt;&lt; <a href='013update_operation.cc.html#L25'>maybe</a><span class="Delimiter">(</span><a href='026call.cc.html#L83'>current_recipe_name</a><span class="Delimiter">())</span> &lt;&lt; <span class="Constant">&quot;couldn't find a 'call-with-continuation-mark' to return to</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L140" class="LineNr">140 </span>  <span class="Conceal">¦</span> <a href='003trace.cc.html#L168'>raise</a> &lt;&lt; <a href='013update_operation.cc.html#L25'>maybe</a><span class="Delimiter">(</span><a href='026call.cc.html#L83'>current_recipe_name</a><span class="Delimiter">())</span> &lt;&lt; <span class="Constant">&quot;call stack:</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; <a href='003trace.cc.html#L197'>end</a><span class="Delimiter">();</span>
<span id="L141" class="LineNr">141 </span>  <span class="Conceal">¦</span> <span class="Normal">for</span> <span class="Delimiter">(</span>call_stack::iterator p = Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span>begin<span class="Delimiter">();</span>  p != Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span><a href='003trace.cc.html#L197'>end</a><span class="Delimiter">();</span>  ++p<span class="Delimiter">)</span>
<span id="L142" class="LineNr">142 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <a href='003trace.cc.html#L168'>raise</a> &lt;&lt; <a href='013update_operation.cc.html#L25'>maybe</a><span class="Delimiter">(</span><a href='026call.cc.html#L83'>current_recipe_name</a><span class="Delimiter">())</span> &lt;&lt; <span class="Constant">&quot;  &quot;</span> &lt;&lt; get<span class="Delimiter">(</span>Recipe<span class="Delimiter">,</span> p<span class="Delimiter">-&gt;</span>running_recipe<span class="Delimiter">).</span>name &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; <a href='003trace.cc.html#L197'>end</a><span class="Delimiter">();</span>
<span id="L143" class="LineNr">143 </span>  <span class="Conceal">¦</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L144" class="LineNr">144 </span>  <span class="Delimiter">}</span>
<span id="L145" class="LineNr">145 </span>  Delimited_continuation[Next_delimited_continuation_id] = call_stack<span class="Delimiter">(</span>Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span>begin<span class="Delimiter">(),</span> base<span class="Delimiter">);</span>
<span id="L146" class="LineNr">146 </span>  <span class="Normal">while</span> <span class="Delimiter">(</span>Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span>begin<span class="Delimiter">()</span> != base<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L147" class="LineNr">147 </span>  <span class="Conceal">¦</span> <span class="Normal">if</span> <span class="Delimiter">(</span>Trace_stream<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L148" class="LineNr">148 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> --Trace_stream<span class="Delimiter">-&gt;</span>callstack_depth<span class="Delimiter">;</span>
<span id="L149" class="LineNr">149 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> assert<span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>callstack_depth &gt;= <span class="Constant">0</span><span class="Delimiter">);</span>
<span id="L150" class="LineNr">150 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L151" class="LineNr">151 </span>  <span class="Conceal">¦</span> Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span>pop_front<span class="Delimiter">();</span>
<span id="L152" class="LineNr">152 </span>  <span class="Delimiter">}</span>
<span id="L153" class="LineNr">153 </span>  <span class="Comment">// return it as the result of the marked call</span>
<span id="L154" class="LineNr">154 </span>  products<span class="Delimiter">.</span>resize<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span id="L155" class="LineNr">155 </span>  products<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>push_back<span class="Delimiter">(</span>Next_delimited_continuation_id<span class="Delimiter">);</span>
<span id="L156" class="LineNr">156 </span>  ++Next_delimited_continuation_id<span class="Delimiter">;</span>
<span id="L157" class="LineNr">157 </span>  <span class="Identifier">break</span><span class="Delimiter">;</span>  <span class="Comment">// continue to process rest of marked call</span>
<span id="L158" class="LineNr">158 </span><span class="Delimiter">}</span>
<span id="L159" class="LineNr">159 </span>
<span id="L160" class="LineNr">160 </span><span class="Delimiter">:(code)</span>
<span id="L161" class="LineNr">161 </span>call_stack::iterator find_base_of_continuation<span class="Delimiter">(</span>call_stack&amp; c<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L162" class="LineNr">162 </span>  <span class="Normal">for</span> <span class="Delimiter">(</span>call_stack::iterator p = c<span class="Delimiter">.</span>begin<span class="Delimiter">();</span> p != c<span class="Delimiter">.</span><a href='003trace.cc.html#L197'>end</a><span class="Delimiter">();</span> ++p<span class="Delimiter">)</span>
<span id="L163" class="LineNr">163 </span>  <span class="Conceal">¦</span> <span class="Normal">if</span> <span class="Delimiter">(</span>p<span class="Delimiter">-&gt;</span>is_base_of_continuation<span class="Delimiter">)</span> <span class="Identifier">return</span> p<span class="Delimiter">;</span>
<span id="L164" class="LineNr">164 </span>  <span class="Identifier">return</span> c<span class="Delimiter">.</span><a href='003trace.cc.html#L197'>end</a><span class="Delimiter">();</span>
<span id="L165" class="LineNr">165 </span><span class="Delimiter">}</span>
<span id="L166" class="LineNr">166 </span>
<span id="L167" class="LineNr">167 </span><span class="Comment">//: overload 'call' for continuations</span>
<span id="L168" class="LineNr">168 </span><span class="Delimiter">:(after &quot;Begin Call&quot;)</span>
<span id="L169" class="LineNr">169 </span><span class="Normal">if</span> <span class="Delimiter">(</span><a href='026call.cc.html#L85'>current_instruction</a><span class="Delimiter">().</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>type<span class="Delimiter">-&gt;</span>atom
<span id="L170" class="LineNr">170 </span>  <span class="Conceal">¦</span> &amp;&amp; <a href='026call.cc.html#L85'>current_instruction</a><span class="Delimiter">().</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>type<span class="Delimiter">-&gt;</span>name == <span class="Constant">&quot;continuation&quot;</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L171" class="LineNr">171 </span>  <span class="Comment">// copy multiple calls on to current call stack</span>
<span id="L172" class="LineNr">172 </span>  assert<span class="Delimiter">(</span>scalar<span class="Delimiter">(</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">)));</span>
<span id="L173" class="LineNr">173 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>Delimited_continuation<span class="Delimiter">.</span>find<span class="Delimiter">(</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">))</span> == Delimited_continuation<span class="Delimiter">.</span><a href='003trace.cc.html#L197'>end</a><span class="Delimiter">())</span>
<span id="L174" class="LineNr">174 </span>  <span class="Conceal">¦</span> <a href='003trace.cc.html#L168'>raise</a> &lt;&lt; <a href='013update_operation.cc.html#L25'>maybe</a><span class="Delimiter">(</span><a href='026call.cc.html#L83'>current_recipe_name</a><span class="Delimiter">())</span> &lt;&lt; <span class="Constant">&quot;no such delimited continuation &quot;</span> &lt;&lt; <a href='026call.cc.html#L85'>current_instruction</a><span class="Delimiter">().</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>original_string &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; <a href='003trace.cc.html#L197'>end</a><span class="Delimiter">();</span>
<span id="L175" class="LineNr">175 </span>  <span class="Normal">const</span> call_stack&amp; new_calls = Delimited_continuation[ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">)</span>]<span class="Delimiter">;</span>
<span id="L176" class="LineNr">176 </span>  <span class="Normal">const</span> call&amp; caller = <span class="Delimiter">(</span><a href='001help.cc.html#L141'>SIZE</a><span class="Delimiter">(</span>new_calls<span class="Delimiter">)</span> &gt; <span class="Constant">1</span><span class="Delimiter">)</span> ? *++new_calls<span class="Delimiter">.</span>begin<span class="Delimiter">()</span> : Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span>front<span class="Delimiter">();</span>
<span id="L177" class="LineNr">177 </span>  <span class="Normal">for</span> <span class="Delimiter">(</span>call_stack::const_reverse_iterator p = new_calls<span class="Delimiter">.</span>rbegin<span class="Delimiter">();</span> p != new_calls<span class="Delimiter">.</span>rend<span class="Delimiter">();</span> ++p<span class="Delimiter">)</span>
<span id="L178" class="LineNr">178 </span>  <span class="Conceal">¦</span> Current_routine<span class="Delimiter">-&gt;</span>calls<span class="Delimiter">.</span>push_front<span class="Delimiter">(</span>*p<span class="Delimiter">);</span>
<span id="L179" class="LineNr">179 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>Trace_stream<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L180" class="LineNr">180 </span>  <span class="Conceal">¦</span> Trace_stream<span class="Delimiter">-&gt;</span>callstack_depth += <a href='001help.cc.html#L141'>SIZE</a><span class="Delimiter">(</span>new_calls<span class="Delimiter">);</span>
<span id="L181" class="LineNr">181 </span>  <span class="Conceal">¦</span> <a href='003trace.cc.html#L161'>trace</a><span class="Delimiter">(</span><span class="Constant">&quot;trace&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;calling delimited continuation; growing callstack depth to &quot;</span> &lt;&lt; Trace_stream<span class="Delimiter">-&gt;</span>callstack_depth &lt;&lt; <a href='003trace.cc.html#L197'>end</a><span class="Delimiter">();</span>
<span id="L182" class="LineNr">182 </span>  <span class="Conceal">¦</span> assert<span class="Delimiter">(</span>Trace_stream<span class="Delimiter">-&gt;</span>callstack_depth &lt; <span class="Constant">9000</span><span class="Delimiter">);</span>  <span class="Comment">// 9998-101 plus cushion</span>
<span id="L183" class="LineNr">183 </span>  <span class="Delimiter">}</span>
<span id="L184" class="LineNr">184 </span>  ++current_step_index<span class="Delimiter">();</span>  <span class="Comment">// skip past the return-continuation-until-mark</span>
<span id="L185" class="LineNr">185 </span>  ingredients<span class="Delimiter">.</span>erase<span class="Delimiter">(</span>ingredients<span class="Delimiter">.</span>begin<span class="Delimiter">());</span>  <span class="Comment">// drop the callee</span>
<span id="L186" class="LineNr">186 </span>  finish_call_housekeeping<span class="Delimiter">(</span><a href='026call.cc.html#L84'>to_instruction</a><span class="Delimiter">(</span>caller<span class="Delimiter">),</span> ingredients<span class="Delimiter">);</span>
<span id="L187" class="LineNr">187 </span>  <span class="Identifier">continue</span><span class="Delimiter">;</span>
<span id="L188" class="LineNr">188 </span><span class="Delimiter">}</span>
</pre>
</body>
</html>
<!-- vim: set foldmethod=manual : -->