html/075channel.mu.html


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
generated by cgit-pink 1.4.1-2-gfad0 (git 2.36.2.497.gbbea4dcf42) at 2025-06-07 14:44:29 +0000
 

25' href='#n425'>425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586

<!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 - 075channel.mu</title>
<meta name="Generator" content="Vim/7.4">
<meta name="plugin-version" content="vim7.4_v2">
<meta name="syntax" content="none">
<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; }
.Conceal { color: #4e4e4e; }
.muScenario { color: #00af00; }
.Special { color: #c00000; }
.Delimiter { color: #800080; }
.SalientComment { color: #00ffff; }
.Comment { color: #9090ff; }
.Comment a { color:#0000ee; text-decoration:underline; }
.Constant { color: #00a0a0; }
.LineNr { color: #444444; }
.muRecipe { color: #ff8700; }
.muControl { color: #c0a020; }
.CommentedCode { color: #6c6c6c; }
.muData { color: #ffff00; }
-->
</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"># Mu synchronizes between routines using channels rather than locks, like</span>
<span id="L2" class="LineNr">  2 </span><span class="Comment"># Erlang and Go.</span>
<span id="L3" class="LineNr">  3 </span><span class="Comment">#</span>
<span id="L4" class="LineNr">  4 </span><span class="Comment"># Key properties of channels:</span>
<span id="L5" class="LineNr">  5 </span><span class="Comment">#</span>
<span id="L6" class="LineNr">  6 </span><span class="Comment">#   a) Writing to a full channel or reading from an empty one will put the</span>
<span id="L7" class="LineNr">  7 </span><span class="Comment">#   current routine in 'waiting' state until the operation can be completed.</span>
<span id="L8" class="LineNr">  8 </span><span class="Comment">#</span>
<span id="L9" class="LineNr">  9 </span><span class="Comment">#   b) Writing to a channel implicitly performs a deep copy. This prevents</span>
<span id="L10" class="LineNr"> 10 </span><span class="Comment">#   addresses from being shared between routines, and therefore eliminates all</span>
<span id="L11" class="LineNr"> 11 </span><span class="Comment">#   possibility of race conditions.</span>
<span id="L12" class="LineNr"> 12 </span><span class="Comment">#</span>
<span id="L13" class="LineNr"> 13 </span><span class="Comment"># There's still a narrow window for race conditions: the inputs passed in</span>
<span id="L14" class="LineNr"> 14 </span><span class="Comment"># to 'start-running'. Pass only channels into routines and you should be fine.</span>
<span id="L15" class="LineNr"> 15 </span><span class="Comment"># Any other mutable inputs will require locks.</span>
<span id="L16" class="LineNr"> 16 </span>
<span id="L17" class="LineNr"> 17 </span><span class="muScenario">scenario</span> channel [
<span id="L18" class="LineNr"> 18 </span>  run [
<span id="L19" class="LineNr"> 19 </span>  <span class="Conceal">¦</span> <span class="Constant">local-scope</span>
<span id="L20" class="LineNr"> 20 </span>  <span class="Conceal">¦</span> <a href='075channel.mu.html#L43'>source</a>:&amp;:<a href='075channel.mu.html#L43'>source</a>:num, <a href='075channel.mu.html#L47'>sink</a>:&amp;:<a href='075channel.mu.html#L47'>sink</a>:num <span class="Special">&lt;-</span> <a href='075channel.mu.html#L51'>new-channel</a> <span class="Constant">3/capacity</span>
<span id="L21" class="LineNr"> 21 </span>  <span class="Conceal">¦</span> <a href='075channel.mu.html#L47'>sink</a> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>,<span class="Constant"> 34</span>
<span id="L22" class="LineNr"> 22 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span>, 11:bool/<span class="Special">raw</span>, <a href='075channel.mu.html#L43'>source</a> <span class="Special">&lt;-</span> read <a href='075channel.mu.html#L43'>source</a>
<span id="L23" class="LineNr"> 23 </span>  ]
<span id="L24" class="LineNr"> 24 </span>  memory-should-contain [
<span id="L25" class="LineNr"> 25 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 34</span>
<span id="L26" class="LineNr"> 26 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># read was successful</span>
<span id="L27" class="LineNr"> 27 </span>  ]
<span id="L28" class="LineNr"> 28 </span>]
<span id="L29" class="LineNr"> 29 </span>
<span id="L30" class="LineNr"> 30 </span><span class="muData">container</span> channel:_elem [
<span id="L31" class="LineNr"> 31 </span>  lock:bool  <span class="Comment"># inefficient but simple: serialize all reads as well as writes</span>
<span id="L32" class="LineNr"> 32 </span>  first-full:num  <span class="Comment"># for write</span>
<span id="L33" class="LineNr"> 33 </span>  first-free:num  <span class="Comment"># for read</span>
<span id="L34" class="LineNr"> 34 </span>  <span class="Comment"># A circular buffer contains values from index first-full up to (but not</span>
<span id="L35" class="LineNr"> 35 </span>  <span class="Comment"># including) index first-free. The reader always modifies it at first-full,</span>
<span id="L36" class="LineNr"> 36 </span>  <span class="Comment"># while the writer always modifies it at first-free.</span>
<span id="L37" class="LineNr"> 37 </span>  data:&amp;:@:_elem
<span id="L38" class="LineNr"> 38 </span>]
<span id="L39" class="LineNr"> 39 </span>
<span id="L40" class="LineNr"> 40 </span><span class="Comment"># Since channels have two ends, and since it's an error to use either end from</span>
<span id="L41" class="LineNr"> 41 </span><span class="Comment"># multiple routines, let's distinguish the ends.</span>
<span id="L42" class="LineNr"> 42 </span>
<span id="L43" class="LineNr"> 43 </span><span class="muData">container</span> <a href='075channel.mu.html#L43'>source</a>:_elem [
<span id="L44" class="LineNr"> 44 </span>  chan:&amp;:channel:_elem
<span id="L45" class="LineNr"> 45 </span>]
<span id="L46" class="LineNr"> 46 </span>
<span id="L47" class="LineNr"> 47 </span><span class="muData">container</span> <a href='075channel.mu.html#L47'>sink</a>:_elem [
<span id="L48" class="LineNr"> 48 </span>  chan:&amp;:channel:_elem
<span id="L49" class="LineNr"> 49 </span>]
<span id="L50" class="LineNr"> 50 </span>
<span id="L51" class="LineNr"> 51 </span><span class="muRecipe">def</span> <a href='075channel.mu.html#L51'>new-channel</a> <a href='075channel.mu.html#L399'>capacity</a>:num<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='075channel.mu.html#L43'>source</a>:_elem, out:&amp;:<a href='075channel.mu.html#L47'>sink</a>:_elem [
<span id="L52" class="LineNr"> 52 </span>  <span class="Constant">local-scope</span>
<span id="L53" class="LineNr"> 53 </span>  <span class="Constant">load-inputs</span>
<span id="L54" class="LineNr"> 54 </span>  result:&amp;:channel:_elem <span class="Special">&lt;-</span> new <span class="Delimiter">{</span>(channel _elem): type<span class="Delimiter">}</span>
<span id="L55" class="LineNr"> 55 </span>  *result <span class="Special">&lt;-</span> put *result, <span class="Constant">first-full:offset</span>,<span class="Constant"> 0</span>
<span id="L56" class="LineNr"> 56 </span>  *result <span class="Special">&lt;-</span> put *result, <span class="Constant">first-free:offset</span>,<span class="Constant"> 0</span>
<span id="L57" class="LineNr"> 57 </span>  <a href='075channel.mu.html#L399'>capacity</a> <span class="Special">&lt;-</span> add <a href='075channel.mu.html#L399'>capacity</a>,<span class="Constant"> 1</span>  <span class="Comment"># unused slot for 'full?' below</span>
<span id="L58" class="LineNr"> 58 </span>  data:&amp;:@:_elem <span class="Special">&lt;-</span> new <span class="Constant">_elem:type</span>, <a href='075channel.mu.html#L399'>capacity</a>
<span id="L59" class="LineNr"> 59 </span>  *result <span class="Special">&lt;-</span> put *result, <span class="Constant">data:offset</span>, data
<span id="L60" class="LineNr"> 60 </span>  in <span class="Special">&lt;-</span> new <span class="Delimiter">{</span>(source _elem): type<span class="Delimiter">}</span>
<span id="L61" class="LineNr"> 61 </span>  *in <span class="Special">&lt;-</span> put *in, <span class="Constant">chan:offset</span>, result
<span id="L62" class="LineNr"> 62 </span>  out <span class="Special">&lt;-</span> new <span class="Delimiter">{</span>(sink _elem): type<span class="Delimiter">}</span>
<span id="L63" class="LineNr"> 63 </span>  *out <span class="Special">&lt;-</span> put *out, <span class="Constant">chan:offset</span>, result
<span id="L64" class="LineNr"> 64 </span>]
<span id="L65" class="LineNr"> 65 </span>
<span id="L66" class="LineNr"> 66 </span><span class="Comment"># write a value to a channel</span>
<span id="L67" class="LineNr"> 67 </span><span class="muRecipe">def</span> <a href='075channel.mu.html#L67'>write</a> out:&amp;:<a href='075channel.mu.html#L47'>sink</a>:_elem, val:_elem<span class="muRecipe"> -&gt; </span>out:&amp;:<a href='075channel.mu.html#L47'>sink</a>:_elem [
<span id="L68" class="LineNr"> 68 </span>  <span class="Constant">local-scope</span>
<span id="L69" class="LineNr"> 69 </span>  <span class="Constant">load-inputs</span>
<span id="L70" class="LineNr"> 70 </span>  assert out, <span class="Constant">[write to null channel]</span>
<span id="L71" class="LineNr"> 71 </span>  chan:&amp;:channel:_elem <span class="Special">&lt;-</span> get *out, <span class="Constant">chan:offset</span>
<span id="L72" class="LineNr"> 72 </span><span class="Constant">  <a href='075channel.mu.html#L72'>&lt;channel-write-initial&gt;</a></span>
<span id="L73" class="LineNr"> 73 </span>  <span class="Comment"># block until lock is acquired AND queue has room</span>
<span id="L74" class="LineNr"> 74 </span>  lock:location <span class="Special">&lt;-</span> get-location *chan, <span class="Constant">lock:offset</span>
<span id="L75" class="LineNr"> 75 </span><span class="CommentedCode">#?   $print [write], 10/newline</span>
<span id="L76" class="LineNr"> 76 </span>  <span class="Delimiter">{</span>
<span id="L77" class="LineNr"> 77 </span><span class="CommentedCode">#?     $print [trying to acquire lock for writing], 10/newline</span>
<span id="L78" class="LineNr"> 78 </span>  <span class="Conceal">¦</span> wait-for-reset-then-set lock
<span id="L79" class="LineNr"> 79 </span><span class="CommentedCode">#?     $print [lock acquired for writing], 10/newline</span>
<span id="L80" class="LineNr"> 80 </span>  <span class="Conceal">¦</span> full?:bool <span class="Special">&lt;-</span> <a href='075channel.mu.html#L381'>channel-full?</a> chan
<span id="L81" class="LineNr"> 81 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> full?
<span id="L82" class="LineNr"> 82 </span><span class="CommentedCode">#?     $print [but channel is full; relinquishing lock], 10/newline</span>
<span id="L83" class="LineNr"> 83 </span>  <span class="Conceal">¦</span> <span class="Comment"># channel is full; relinquish lock and give a reader the opportunity to</span>
<span id="L84" class="LineNr"> 84 </span>  <span class="Conceal">¦</span> <span class="Comment"># create room on it</span>
<span id="L85" class="LineNr"> 85 </span>  <span class="Conceal">¦</span> reset lock
<span id="L86" class="LineNr"> 86 </span>  <span class="Conceal">¦</span> current-routine-is-blocked
<span id="L87" class="LineNr"> 87 </span>  <span class="Conceal">¦</span> switch  <span class="Comment"># avoid spinlocking</span>
<span id="L88" class="LineNr"> 88 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
<span id="L89" class="LineNr"> 89 </span>  <span class="Delimiter">}</span>
<span id="L90" class="LineNr"> 90 </span>  current-routine-is-unblocked
<span id="L91" class="LineNr"> 91 </span><span class="CommentedCode">#?   $print [performing write], 10/newline</span>
<span id="L92" class="LineNr"> 92 </span>  <span class="Comment"># store a deep copy of val</span>
<span id="L93" class="LineNr"> 93 </span>  circular-buffer:&amp;:@:_elem <span class="Special">&lt;-</span> get *chan, <span class="Constant">data:offset</span>
<span id="L94" class="LineNr"> 94 </span>  free:num <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-free:offset</span>
<span id="L95" class="LineNr"> 95 </span>  val-copy:_elem <span class="Special">&lt;-</span> deep-copy val  <span class="Comment"># on this instruction rests all Mu's concurrency-safety</span>
<span id="L96" class="LineNr"> 96 </span>  *circular-buffer <span class="Special">&lt;-</span> put-index *circular-buffer, free, val-copy
<span id="L97" class="LineNr"> 97 </span>  <span class="Comment"># mark its slot as filled</span>
<span id="L98" class="LineNr"> 98 </span>  free <span class="Special">&lt;-</span> add free,<span class="Constant"> 1</span>
<span id="L99" class="LineNr"> 99 </span>  <span class="Delimiter">{</span>
<span id="L100" class="LineNr">100 </span>  <span class="Conceal">¦</span> <span class="Comment"># wrap free around to 0 if necessary</span>
<span id="L101" class="LineNr">101 </span>  <span class="Conceal">¦</span> len:num <span class="Special">&lt;-</span> length *circular-buffer
<span id="L102" class="LineNr">102 </span>  <span class="Conceal">¦</span> at-end?:bool <span class="Special">&lt;-</span> greater-or-equal free, len
<span id="L103" class="LineNr">103 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-end?
<span id="L104" class="LineNr">104 </span>  <span class="Conceal">¦</span> free <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L105" class="LineNr">105 </span>  <span class="Delimiter">}</span>
<span id="L106" class="LineNr">106 </span>  <span class="Comment"># write back</span>
<span id="L107" class="LineNr">107 </span>  *chan <span class="Special">&lt;-</span> put *chan, <span class="Constant">first-free:offset</span>, free
<span id="L108" class="LineNr">108 </span><span class="CommentedCode">#?   $print [relinquishing lock after writing], 10/newline</span>
<span id="L109" class="LineNr">109 </span>  reset lock
<span id="L110" class="LineNr">110 </span>]
<span id="L111" class="LineNr">111 </span>
<span id="L112" class="LineNr">112 </span><span class="Comment"># read a value from a channel</span>
<span id="L113" class="LineNr">113 </span><span class="muRecipe">def</span> read in:&amp;:<a href='075channel.mu.html#L43'>source</a>:_elem<span class="muRecipe"> -&gt; </span>result:_elem, eof?:bool, in:&amp;:<a href='075channel.mu.html#L43'>source</a>:_elem [
<span id="L114" class="LineNr">114 </span>  <span class="Constant">local-scope</span>
<span id="L115" class="LineNr">115 </span>  <span class="Constant">load-inputs</span>
<span id="L116" class="LineNr">116 </span>  assert in, <span class="Constant">[read on null channel]</span>
<span id="L117" class="LineNr">117 </span>  eof? <span class="Special">&lt;-</span> copy <span class="Constant">0/false</span>  <span class="Comment"># default result</span>
<span id="L118" class="LineNr">118 </span>  chan:&amp;:channel:_elem <span class="Special">&lt;-</span> get *in, <span class="Constant">chan:offset</span>
<span id="L119" class="LineNr">119 </span>  <span class="Comment"># block until lock is acquired AND queue has data</span>
<span id="L120" class="LineNr">120 </span>  lock:location <span class="Special">&lt;-</span> get-location *chan, <span class="Constant">lock:offset</span>
<span id="L121" class="LineNr">121 </span><span class="CommentedCode">#?   $print [read], 10/newline</span>
<span id="L122" class="LineNr">122 </span>  <span class="Delimiter">{</span>
<span id="L123" class="LineNr">123 </span><span class="CommentedCode">#?     $print [trying to acquire lock for reading], 10/newline</span>
<span id="L124" class="LineNr">124 </span>  <span class="Conceal">¦</span> wait-for-reset-then-set lock
<span id="L125" class="LineNr">125 </span><span class="CommentedCode">#?     $print [lock acquired for reading], 10/newline</span>
<span id="L126" class="LineNr">126 </span>  <span class="Conceal">¦</span> empty?:bool <span class="Special">&lt;-</span> <a href='075channel.mu.html#L370'>channel-empty?</a> chan
<span id="L127" class="LineNr">127 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> empty?
<span id="L128" class="LineNr">128 </span><span class="CommentedCode">#?     $print [but channel is empty; relinquishing lock], 10/newline</span>
<span id="L129" class="LineNr">129 </span>  <span class="Conceal">¦</span> <span class="Comment"># channel is empty; relinquish lock and give a writer the opportunity to</span>
<span id="L130" class="LineNr">130 </span>  <span class="Conceal">¦</span> <span class="Comment"># add to it</span>
<span id="L131" class="LineNr">131 </span>  <span class="Conceal">¦</span> reset lock
<span id="L132" class="LineNr">132 </span>  <span class="Conceal">¦</span> current-routine-is-blocked
<span id="L133" class="LineNr">133 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> <a href='075channel.mu.html#L133'>&lt;channel-read-empty&gt;</a></span>
<span id="L134" class="LineNr">134 </span>  <span class="Conceal">¦</span> switch  <span class="Comment"># avoid spinlocking</span>
<span id="L135" class="LineNr">135 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
<span id="L136" class="LineNr">136 </span>  <span class="Delimiter">}</span>
<span id="L137" class="LineNr">137 </span>  current-routine-is-unblocked
<span id="L138" class="LineNr">138 </span>  <span class="Comment"># pull result off</span>
<span id="L139" class="LineNr">139 </span>  full:num <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-full:offset</span>
<span id="L140" class="LineNr">140 </span>  circular-buffer:&amp;:@:_elem <span class="Special">&lt;-</span> get *chan, <span class="Constant">data:offset</span>
<span id="L141" class="LineNr">141 </span>  result <span class="Special">&lt;-</span> index *circular-buffer, full
<span id="L142" class="LineNr">142 </span>  <span class="Comment"># clear the slot</span>
<span id="L143" class="LineNr">143 </span>  empty:&amp;:_elem <span class="Special">&lt;-</span> new <span class="Constant">_elem:type</span>
<span id="L144" class="LineNr">144 </span>  *circular-buffer <span class="Special">&lt;-</span> put-index *circular-buffer, full, *empty
<span id="L145" class="LineNr">145 </span>  <span class="Comment"># mark its slot as empty</span>
<span id="L146" class="LineNr">146 </span>  full <span class="Special">&lt;-</span> add full,<span class="Constant"> 1</span>
<span id="L147" class="LineNr">147 </span>  <span class="Delimiter">{</span>
<span id="L148" class="LineNr">148 </span>  <span class="Conceal">¦</span> <span class="Comment"># wrap full around to 0 if necessary</span>
<span id="L149" class="LineNr">149 </span>  <span class="Conceal">¦</span> len:num <span class="Special">&lt;-</span> length *circular-buffer
<span id="L150" class="LineNr">150 </span>  <span class="Conceal">¦</span> at-end?:bool <span class="Special">&lt;-</span> greater-or-equal full, len
<span id="L151" class="LineNr">151 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-end?
<span id="L152" class="LineNr">152 </span>  <span class="Conceal">¦</span> full <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L153" class="LineNr">153 </span>  <span class="Delimiter">}</span>
<span id="L154" class="LineNr">154 </span>  <span class="Comment"># write back</span>
<span id="L155" class="LineNr">155 </span>  *chan <span class="Special">&lt;-</span> put *chan, <span class="Constant">first-full:offset</span>, full
<span id="L156" class="LineNr">156 </span><span class="CommentedCode">#?   $print [relinquishing lock after reading], 10/newline</span>
<span id="L157" class="LineNr">157 </span>  reset lock
<span id="L158" class="LineNr">158 </span>]
<span id="L159" class="LineNr">159 </span>
<span id="L160" class="LineNr">160 </span><span class="Comment"># todo: create a notion of iterator and iterable so we can read/write whole</span>
<span id="L161" class="LineNr">161 </span><span class="Comment"># aggregates (arrays, lists, ..) of _elems at once.</span>
<span id="L162" class="LineNr">162 </span>
<span id="L163" class="LineNr">163 </span><span class="muScenario">scenario</span> channel-initialization [
<span id="L164" class="LineNr">164 </span>  run [
<span id="L165" class="LineNr">165 </span>  <span class="Conceal">¦</span> <span class="Constant">local-scope</span>
<span id="L166" class="LineNr">166 </span>  <span class="Conceal">¦</span> <a href='075channel.mu.html#L43'>source</a>:&amp;:<a href='075channel.mu.html#L43'>source</a>:num <span class="Special">&lt;-</span> <a href='075channel.mu.html#L51'>new-channel</a> <span class="Constant">3/capacity</span>
<span id="L167" class="LineNr">167 </span>  <span class="Conceal">¦</span> chan:&amp;:channel:num <span class="Special">&lt;-</span> get *source, <span class="Constant">chan:offset</span>
<span id="L168" class="LineNr">168 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-full:offset</span>
<span id="L169" class="LineNr">169 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-free:offset</span>
<span id="L170" class="LineNr">170 </span>  ]
<span id="L171" class="LineNr">171 </span>  memory-should-contain [
<span id="L172" class="LineNr">172 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># first-full</span>
<span id="L173" class="LineNr">173 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># first-free</span>
<span id="L174" class="LineNr">174 </span>  ]
<span id="L175" class="LineNr">175 </span>]
<span id="L176" class="LineNr">176 </span>
<span id="L177" class="LineNr">177 </span><span class="muScenario">scenario</span> channel-write-increments-free [
<span id="L178" class="LineNr">178 </span>  <span class="Constant">local-scope</span>
<span id="L179" class="LineNr">179 </span>  _, <a href='075channel.mu.html#L47'>sink</a>:&amp;:<a href='075channel.mu.html#L47'>sink</a>:num <span class="Special">&lt;-</span> <a href='075channel.mu.html#L51'>new-channel</a> <span class="Constant">3/capacity</span>
<span id="L180" class="LineNr">180 </span>  run [
<span id="L181" class="LineNr">181 </span>  <span class="Conceal">¦</span> <a href='075channel.mu.html#L47'>sink</a> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>,<span class="Constant"> 34</span>
<span id="L182" class="LineNr">182 </span>  <span class="Conceal">¦</span> chan:&amp;:channel:num <span class="Special">&lt;-</span> get *sink, <span class="Constant">chan:offset</span>
<span id="L183" class="LineNr">183 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-full:offset</span>
<span id="L184" class="LineNr">184 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-free:offset</span>
<span id="L185" class="LineNr">185 </span>  ]
<span id="L186" class="LineNr">186 </span>  memory-should-contain [
<span id="L187" class="LineNr">187 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># first-full</span>
<span id="L188" class="LineNr">188 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># first-free</span>
<span id="L189" class="LineNr">189 </span>  ]
<span id="L190" class="LineNr">190 </span>]
<span id="L191" class="LineNr">191 </span>
<span id="L192" class="LineNr">192 </span><span class="muScenario">scenario</span> channel-read-increments-full [
<span id="L193" class="LineNr">193 </span>  <span class="Constant">local-scope</span>
<span id="L194" class="LineNr">194 </span>  <a href='075channel.mu.html#L43'>source</a>:&amp;:<a href='075channel.mu.html#L43'>source</a>:num, <a href='075channel.mu.html#L47'>sink</a>:&amp;:<a href='075channel.mu.html#L47'>sink</a>:num <span class="Special">&lt;-</span> <a href='075channel.mu.html#L51'>new-channel</a> <span class="Constant">3/capacity</span>
<span id="L195" class="LineNr">195 </span>  <a href='075channel.mu.html#L47'>sink</a> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>,<span class="Constant"> 34</span>
<span id="L196" class="LineNr">196 </span>  run [
<span id="L197" class="LineNr">197 </span>  <span class="Conceal">¦</span> _, _, <a href='075channel.mu.html#L43'>source</a> <span class="Special">&lt;-</span> read <a href='075channel.mu.html#L43'>source</a>
<span id="L198" class="LineNr">198 </span>  <span class="Conceal">¦</span> chan:&amp;:channel:num <span class="Special">&lt;-</span> get *source, <span class="Constant">chan:offset</span>
<span id="L199" class="LineNr">199 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-full:offset</span>
<span id="L200" class="LineNr">200 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-free:offset</span>
<span id="L201" class="LineNr">201 </span>  ]
<span id="L202" class="LineNr">202 </span>  memory-should-contain [
<span id="L203" class="LineNr">203 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># first-full</span>
<span id="L204" class="LineNr">204 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># first-free</span>
<span id="L205" class="LineNr">205 </span>  ]
<span id="L206" class="LineNr">206 </span>]
<span id="L207" class="LineNr">207 </span>
<span id="L208" class="LineNr">208 </span><span class="muScenario">scenario</span> channel-wrap [
<span id="L209" class="LineNr">209 </span>  <span class="Constant">local-scope</span>
<span id="L210" class="LineNr">210 </span>  <span class="Comment"># channel with just 1 slot</span>
<span id="L211" class="LineNr">211 </span>  <a href='075channel.mu.html#L43'>source</a>:&amp;:<a href='075channel.mu.html#L43'>source</a>:num, <a href='075channel.mu.html#L47'>sink</a>:&amp;:<a href='075channel.mu.html#L47'>sink</a>:num <span class="Special">&lt;-</span> <a href='075channel.mu.html#L51'>new-channel</a> <span class="Constant">1/capacity</span>
<span id="L212" class="LineNr">212 </span>  chan:&amp;:channel:num <span class="Special">&lt;-</span> get *source, <span class="Constant">chan:offset</span>
<span id="L213" class="LineNr">213 </span>  <span class="Comment"># write and read a value</span>
<span id="L214" class="LineNr">214 </span>  <a href='075channel.mu.html#L47'>sink</a> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>,<span class="Constant"> 34</span>
<span id="L215" class="LineNr">215 </span>  _, _, <a href='075channel.mu.html#L43'>source</a> <span class="Special">&lt;-</span> read <a href='075channel.mu.html#L43'>source</a>
<span id="L216" class="LineNr">216 </span>  run [
<span id="L217" class="LineNr">217 </span>  <span class="Conceal">¦</span> <span class="Comment"># first-free will now be 1</span>
<span id="L218" class="LineNr">218 </span>  <span class="Conceal">¦</span> 10:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-free:offset</span>
<span id="L219" class="LineNr">219 </span>  <span class="Conceal">¦</span> 11:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-free:offset</span>
<span id="L220" class="LineNr">220 </span>  <span class="Conceal">¦</span> <span class="Comment"># write second value, verify that first-free wraps</span>
<span id="L221" class="LineNr">221 </span>  <span class="Conceal">¦</span> <a href='075channel.mu.html#L47'>sink</a> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>,<span class="Constant"> 34</span>
<span id="L222" class="LineNr">222 </span>  <span class="Conceal">¦</span> 20:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-free:offset</span>
<span id="L223" class="LineNr">223 </span>  <span class="Conceal">¦</span> <span class="Comment"># read second value, verify that first-full wraps</span>
<span id="L224" class="LineNr">224 </span>  <span class="Conceal">¦</span> _, _, <a href='075channel.mu.html#L43'>source</a> <span class="Special">&lt;-</span> read <a href='075channel.mu.html#L43'>source</a>
<span id="L225" class="LineNr">225 </span>  <span class="Conceal">¦</span> 30:num/<span class="Special">raw</span> <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-full:offset</span>
<span id="L226" class="LineNr">226 </span>  ]
<span id="L227" class="LineNr">227 </span>  memory-should-contain [
<span id="L228" class="LineNr">228 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># first-free after first write</span>
<span id="L229" class="LineNr">229 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># first-full after first read</span>
<span id="L230" class="LineNr">230 </span>  <span class="Conceal">¦</span><span class="Constant"> 20</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># first-free after second write, wrapped</span>
<span id="L231" class="LineNr">231 </span>  <span class="Conceal">¦</span><span class="Constant"> 30</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># first-full after second read, wrapped</span>
<span id="L232" class="LineNr">232 </span>  ]
<span id="L233" class="LineNr">233 </span>]
<span id="L234" class="LineNr">234 </span>
<span id="L235" class="LineNr">235 </span><span class="muScenario">scenario</span> channel-new-empty-not-full [
<span id="L236" class="LineNr">236 </span>  run [
<span id="L237" class="LineNr">237 </span>  <span class="Conceal">¦</span> <span class="Constant">local-scope</span>
<span id="L238" class="LineNr">238 </span>  <span class="Conceal">¦</span> <a href='075channel.mu.html#L43'>source</a>:&amp;:<a href='075channel.mu.html#L43'>source</a>:num <span class="Special">&lt;-</span> <a href='075channel.mu.html#L51'>new-channel</a> <span class="Constant">3/capacity</span>
<span id="L239" class="LineNr">239 </span>  <span class="Conceal">¦</span> chan:&amp;:channel:num <span class="Special">&lt;-</span> get *source, <span class="Constant">chan:offset</span>
<span id="L240" class="LineNr">240 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L370'>channel-empty?</a> chan
<span id="L241" class="LineNr">241 </span>  <span class="Conceal">¦</span> 11:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L381'>channel-full?</a> chan
<span id="L242" class="LineNr">242 </span>  ]
<span id="L243" class="LineNr">243 </span>  memory-should-contain [
<span id="L244" class="LineNr">244 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># empty?</span>
<span id="L245" class="LineNr">245 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># full?</span>
<span id="L246" class="LineNr">246 </span>  ]
<span id="L247" class="LineNr">247 </span>]
<span id="L248" class="LineNr">248 </span>
<span id="L249" class="LineNr">249 </span><span class="muScenario">scenario</span> channel-write-not-empty [
<span id="L250" class="LineNr">250 </span>  <span class="Constant">local-scope</span>
<span id="L251" class="LineNr">251 </span>  <a href='075channel.mu.html#L43'>source</a>:&amp;:<a href='075channel.mu.html#L43'>source</a>:num, <a href='075channel.mu.html#L47'>sink</a>:&amp;:<a href='075channel.mu.html#L47'>sink</a>:num <span class="Special">&lt;-</span> <a href='075channel.mu.html#L51'>new-channel</a> <span class="Constant">3/capacity</span>
<span id="L252" class="LineNr">252 </span>  chan:&amp;:channel:num <span class="Special">&lt;-</span> get *source, <span class="Constant">chan:offset</span>
<span id="L253" class="LineNr">253 </span>  run [
<span id="L254" class="LineNr">254 </span>  <span class="Conceal">¦</span> <a href='075channel.mu.html#L47'>sink</a> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>,<span class="Constant"> 34</span>
<span id="L255" class="LineNr">255 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L370'>channel-empty?</a> chan
<span id="L256" class="LineNr">256 </span>  <span class="Conceal">¦</span> 11:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L381'>channel-full?</a> chan
<span id="L257" class="LineNr">257 </span>  ]
<span id="L258" class="LineNr">258 </span>  memory-should-contain [
<span id="L259" class="LineNr">259 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># empty?</span>
<span id="L260" class="LineNr">260 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># full?</span>
<span id="L261" class="LineNr">261 </span>  ]
<span id="L262" class="LineNr">262 </span>]
<span id="L263" class="LineNr">263 </span>
<span id="L264" class="LineNr">264 </span><span class="muScenario">scenario</span> channel-write-full [
<span id="L265" class="LineNr">265 </span>  <span class="Constant">local-scope</span>
<span id="L266" class="LineNr">266 </span>  <a href='075channel.mu.html#L43'>source</a>:&amp;:<a href='075channel.mu.html#L43'>source</a>:num, <a href='075channel.mu.html#L47'>sink</a>:&amp;:<a href='075channel.mu.html#L47'>sink</a>:num <span class="Special">&lt;-</span> <a href='075channel.mu.html#L51'>new-channel</a> <span class="Constant">1/capacity</span>
<span id="L267" class="LineNr">267 </span>  chan:&amp;:channel:num <span class="Special">&lt;-</span> get *source, <span class="Constant">chan:offset</span>
<span id="L268" class="LineNr">268 </span>  run [
<span id="L269" class="LineNr">269 </span>  <span class="Conceal">¦</span> <a href='075channel.mu.html#L47'>sink</a> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>,<span class="Constant"> 34</span>
<span id="L270" class="LineNr">270 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L370'>channel-empty?</a> chan
<span id="L271" class="LineNr">271 </span>  <span class="Conceal">¦</span> 11:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L381'>channel-full?</a> chan
<span id="L272" class="LineNr">272 </span>  ]
<span id="L273" class="LineNr">273 </span>  memory-should-contain [
<span id="L274" class="LineNr">274 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># empty?</span>
<span id="L275" class="LineNr">275 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># full?</span>
<span id="L276" class="LineNr">276 </span>  ]
<span id="L277" class="LineNr">277 </span>]
<span id="L278" class="LineNr">278 </span>
<span id="L279" class="LineNr">279 </span><span class="muScenario">scenario</span> channel-read-not-full [
<span id="L280" class="LineNr">280 </span>  <span class="Constant">local-scope</span>
<span id="L281" class="LineNr">281 </span>  <a href='075channel.mu.html#L43'>source</a>:&amp;:<a href='075channel.mu.html#L43'>source</a>:num, <a href='075channel.mu.html#L47'>sink</a>:&amp;:<a href='075channel.mu.html#L47'>sink</a>:num <span class="Special">&lt;-</span> <a href='075channel.mu.html#L51'>new-channel</a> <span class="Constant">1/capacity</span>
<span id="L282" class="LineNr">282 </span>  chan:&amp;:channel:num <span class="Special">&lt;-</span> get *source, <span class="Constant">chan:offset</span>
<span id="L283" class="LineNr">283 </span>  <a href='075channel.mu.html#L47'>sink</a> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>,<span class="Constant"> 34</span>
<span id="L284" class="LineNr">284 </span>  run [
<span id="L285" class="LineNr">285 </span>  <span class="Conceal">¦</span> _, _, <a href='075channel.mu.html#L43'>source</a> <span class="Special">&lt;-</span> read <a href='075channel.mu.html#L43'>source</a>
<span id="L286" class="LineNr">286 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L370'>channel-empty?</a> chan
<span id="L287" class="LineNr">287 </span>  <span class="Conceal">¦</span> 11:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L381'>channel-full?</a> chan
<span id="L288" class="LineNr">288 </span>  ]
<span id="L289" class="LineNr">289 </span>  memory-should-contain [
<span id="L290" class="LineNr">290 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># empty?</span>
<span id="L291" class="LineNr">291 </span>  <span class="Conceal">¦</span><span class="Constant"> 11</span> <span class="Special">&lt;-</span><span class="Constant"> 0</span>  <span class="Comment"># full?</span>
<span id="L292" class="LineNr">292 </span>  ]
<span id="L293" class="LineNr">293 </span>]
<span id="L294" class="LineNr">294 </span>
<span id="L295" class="LineNr">295 </span><span class="muScenario">scenario</span> channel-clear [
<span id="L296" class="LineNr">296 </span>  <span class="Constant">local-scope</span>
<span id="L297" class="LineNr">297 </span>  <span class="Comment"># create a channel with a few items</span>
<span id="L298" class="LineNr">298 </span>  <a href='075channel.mu.html#L43'>source</a>:&amp;:<a href='075channel.mu.html#L43'>source</a>:num, <a href='075channel.mu.html#L47'>sink</a>:&amp;:<a href='075channel.mu.html#L47'>sink</a>:num <span class="Special">&lt;-</span> <a href='075channel.mu.html#L51'>new-channel</a> <span class="Constant">3/capacity</span>
<span id="L299" class="LineNr">299 </span>  chan:&amp;:channel:num <span class="Special">&lt;-</span> get *sink, <span class="Constant">chan:offset</span>
<span id="L300" class="LineNr">300 </span>  <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>,<span class="Constant"> 30</span>
<span id="L301" class="LineNr">301 </span>  <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>,<span class="Constant"> 31</span>
<span id="L302" class="LineNr">302 </span>  <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>,<span class="Constant"> 32</span>
<span id="L303" class="LineNr">303 </span>  run [
<span id="L304" class="LineNr">304 </span>  <span class="Conceal">¦</span> <a href='075channel.mu.html#L312'>clear</a> <a href='075channel.mu.html#L43'>source</a>
<span id="L305" class="LineNr">305 </span>  <span class="Conceal">¦</span> 10:bool/<span class="Special">raw</span> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L370'>channel-empty?</a> chan
<span id="L306" class="LineNr">306 </span>  ]
<span id="L307" class="LineNr">307 </span>  memory-should-contain [
<span id="L308" class="LineNr">308 </span>  <span class="Conceal">¦</span><span class="Constant"> 10</span> <span class="Special">&lt;-</span><span class="Constant"> 1</span>  <span class="Comment"># after the call to 'clear', the channel should be empty</span>
<span id="L309" class="LineNr">309 </span>  ]
<span id="L310" class="LineNr">310 </span>]
<span id="L311" class="LineNr">311 </span>
<span id="L312" class="LineNr">312 </span><span class="muRecipe">def</span> <a href='075channel.mu.html#L312'>clear</a> in:&amp;:<a href='075channel.mu.html#L43'>source</a>:_elem<span class="muRecipe"> -&gt; </span>in:&amp;:<a href='075channel.mu.html#L43'>source</a>:_elem [
<span id="L313" class="LineNr">313 </span>  <span class="Constant">local-scope</span>
<span id="L314" class="LineNr">314 </span>  <span class="Constant">load-inputs</span>
<span id="L315" class="LineNr">315 </span>  chan:&amp;:channel:_elem <span class="Special">&lt;-</span> get *in, <span class="Constant">chan:offset</span>
<span id="L316" class="LineNr">316 </span>  <span class="Delimiter">{</span>
<span id="L317" class="LineNr">317 </span>  <span class="Conceal">¦</span> empty?:bool <span class="Special">&lt;-</span> <a href='075channel.mu.html#L370'>channel-empty?</a> chan
<span id="L318" class="LineNr">318 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> empty?
<span id="L319" class="LineNr">319 </span>  <span class="Conceal">¦</span> _, _, in <span class="Special">&lt;-</span> read in
<span id="L320" class="LineNr">320 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
<span id="L321" class="LineNr">321 </span>  <span class="Delimiter">}</span>
<span id="L322" class="LineNr">322 </span>]
<span id="L323" class="LineNr">323 </span>
<span id="L324" class="LineNr">324 </span><span class="SalientComment">## cancelling channels</span>
<span id="L325" class="LineNr">325 </span>
<span id="L326" class="LineNr">326 </span><span class="Comment"># every channel comes with a boolean signifying if it's been closed</span>
<span id="L327" class="LineNr">327 </span><span class="Comment"># initially this boolean is false</span>
<span id="L328" class="LineNr">328 </span><span class="muData">container</span> channel:_elem [
<span id="L329" class="LineNr">329 </span>  closed?:bool
<span id="L330" class="LineNr">330 </span>]
<span id="L331" class="LineNr">331 </span>
<span id="L332" class="LineNr">332 </span><span class="Comment"># a channel can be closed from either the source or the sink</span>
<span id="L333" class="LineNr">333 </span><span class="Comment"># both routines can modify the 'closed?' bit, but they can only ever set it, so this is a benign race</span>
<span id="L334" class="LineNr">334 </span><span class="muRecipe">def</span> close x:&amp;:<a href='075channel.mu.html#L43'>source</a>:_elem<span class="muRecipe"> -&gt; </span>x:&amp;:<a href='075channel.mu.html#L43'>source</a>:_elem [
<span id="L335" class="LineNr">335 </span>  <span class="Constant">local-scope</span>
<span id="L336" class="LineNr">336 </span>  <span class="Constant">load-inputs</span>
<span id="L337" class="LineNr">337 </span>  chan:&amp;:channel:_elem <span class="Special">&lt;-</span> get *x, <span class="Constant">chan:offset</span>
<span id="L338" class="LineNr">338 </span>  *chan <span class="Special">&lt;-</span> put *chan, <span class="Constant">closed?:offset</span>, <span class="Constant">1/true</span>
<span id="L339" class="LineNr">339 </span>]
<span id="L340" class="LineNr">340 </span><span class="muRecipe">def</span> close x:&amp;:<a href='075channel.mu.html#L47'>sink</a>:_elem<span class="muRecipe"> -&gt; </span>x:&amp;:<a href='075channel.mu.html#L47'>sink</a>:_elem [
<span id="L341" class="LineNr">341 </span>  <span class="Constant">local-scope</span>
<span id="L342" class="LineNr">342 </span>  <span class="Constant">load-inputs</span>
<span id="L343" class="LineNr">343 </span>  chan:&amp;:channel:_elem <span class="Special">&lt;-</span> get *x, <span class="Constant">chan:offset</span>
<span id="L344" class="LineNr">344 </span>  *chan <span class="Special">&lt;-</span> put *chan, <span class="Constant">closed?:offset</span>, <span class="Constant">1/true</span>
<span id="L345" class="LineNr">345 </span>]
<span id="L346" class="LineNr">346 </span>
<span id="L347" class="LineNr">347 </span><span class="Comment"># once a channel is closed from one side, no further operations are expected from that side</span>
<span id="L348" class="LineNr">348 </span><span class="Comment"># if a channel is closed for reading,</span>
<span id="L349" class="LineNr">349 </span><span class="Comment">#   no further writes will be let through</span>
<span id="L350" class="LineNr">350 </span><span class="Comment"># if a channel is closed for writing,</span>
<span id="L351" class="LineNr">351 </span><span class="Comment">#   future reads continue until the channel empties,</span>
<span id="L352" class="LineNr">352 </span><span class="Comment">#   then the channel is also closed for reading</span>
<span id="L353" class="LineNr">353 </span><span class="muRecipe">after</span> <span class="Constant"><a href='075channel.mu.html#L72'>&lt;channel-write-initial&gt;</a></span> [
<span id="L354" class="LineNr">354 </span>  closed?:bool <span class="Special">&lt;-</span> get *chan, <span class="Constant">closed?:offset</span>
<span id="L355" class="LineNr">355 </span>  <span class="muControl">return-if</span> closed?
<span id="L356" class="LineNr">356 </span>]
<span id="L357" class="LineNr">357 </span><span class="muRecipe">after</span> <span class="Constant"><a href='075channel.mu.html#L133'>&lt;channel-read-empty&gt;</a></span> [
<span id="L358" class="LineNr">358 </span>  closed?:bool <span class="Special">&lt;-</span> get *chan, <span class="Constant">closed?:offset</span>
<span id="L359" class="LineNr">359 </span>  <span class="Delimiter">{</span>
<span id="L360" class="LineNr">360 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> closed?
<span id="L361" class="LineNr">361 </span>  <span class="Conceal">¦</span> empty-result:&amp;:_elem <span class="Special">&lt;-</span> new <span class="Constant">_elem:type</span>
<span id="L362" class="LineNr">362 </span>  <span class="Conceal">¦</span> current-routine-is-unblocked
<span id="L363" class="LineNr">363 </span>  <span class="Conceal">¦</span> <span class="muControl">return</span> *empty-result, <span class="Constant">1/true</span>
<span id="L364" class="LineNr">364 </span>  <span class="Delimiter">}</span>
<span id="L365" class="LineNr">365 </span>]
<span id="L366" class="LineNr">366 </span>
<span id="L367" class="LineNr">367 </span><span class="SalientComment">## helpers</span>
<span id="L368" class="LineNr">368 </span>
<span id="L369" class="LineNr">369 </span><span class="Comment"># An empty channel has first-free and first-full both at the same value.</span>
<span id="L370" class="LineNr">370 </span><span class="muRecipe">def</span> <a href='075channel.mu.html#L370'>channel-empty?</a> chan:&amp;:channel:_elem<span class="muRecipe"> -&gt; </span>result:bool [
<span id="L371" class="LineNr">371 </span>  <span class="Constant">local-scope</span>
<span id="L372" class="LineNr">372 </span>  <span class="Constant">load-inputs</span>
<span id="L373" class="LineNr">373 </span>  <span class="Comment"># return chan.first-full == chan.first-free</span>
<span id="L374" class="LineNr">374 </span>  full:num <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-full:offset</span>
<span id="L375" class="LineNr">375 </span>  free:num <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-free:offset</span>
<span id="L376" class="LineNr">376 </span>  result <span class="Special">&lt;-</span> equal full, free
<span id="L377" class="LineNr">377 </span>]
<span id="L378" class="LineNr">378 </span>
<span id="L379" class="LineNr">379 </span><span class="Comment"># A full channel has first-free just before first-full, wasting one slot.</span>
<span id="L380" class="LineNr">380 </span><span class="Comment"># (Other alternatives: <a href="https://www.snellman.net/blog/archive/2016-12-13-ring-buffers)">https://www.snellman.net/blog/archive/2016-12-13-ring-buffers)</a></span>
<span id="L381" class="LineNr">381 </span><span class="muRecipe">def</span> <a href='075channel.mu.html#L381'>channel-full?</a> chan:&amp;:channel:_elem<span class="muRecipe"> -&gt; </span>result:bool [
<span id="L382" class="LineNr">382 </span>  <span class="Constant">local-scope</span>
<span id="L383" class="LineNr">383 </span>  <span class="Constant">load-inputs</span>
<span id="L384" class="LineNr">384 </span>  <span class="Comment"># tmp = chan.first-free + 1</span>
<span id="L385" class="LineNr">385 </span>  tmp:num <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-free:offset</span>
<span id="L386" class="LineNr">386 </span>  tmp <span class="Special">&lt;-</span> add tmp,<span class="Constant"> 1</span>
<span id="L387" class="LineNr">387 </span>  <span class="Delimiter">{</span>
<span id="L388" class="LineNr">388 </span>  <span class="Conceal">¦</span> <span class="Comment"># if tmp == chan.capacity, tmp = 0</span>
<span id="L389" class="LineNr">389 </span>  <span class="Conceal">¦</span> len:num <span class="Special">&lt;-</span> <a href='075channel.mu.html#L399'>capacity</a> chan
<span id="L390" class="LineNr">390 </span>  <span class="Conceal">¦</span> at-end?:bool <span class="Special">&lt;-</span> greater-or-equal tmp, len
<span id="L391" class="LineNr">391 </span>  <span class="Conceal">¦</span> <span class="muControl">break-unless</span> at-end?
<span id="L392" class="LineNr">392 </span>  <span class="Conceal">¦</span> tmp <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L393" class="LineNr">393 </span>  <span class="Delimiter">}</span>
<span id="L394" class="LineNr">394 </span>  <span class="Comment"># return chan.first-full == tmp</span>
<span id="L395" class="LineNr">395 </span>  full:num <span class="Special">&lt;-</span> get *chan, <span class="Constant">first-full:offset</span>
<span id="L396" class="LineNr">396 </span>  result <span class="Special">&lt;-</span> equal full, tmp
<span id="L397" class="LineNr">397 </span>]
<span id="L398" class="LineNr">398 </span>
<span id="L399" class="LineNr">399 </span><span class="muRecipe">def</span> <a href='075channel.mu.html#L399'>capacity</a> chan:&amp;:channel:_elem<span class="muRecipe"> -&gt; </span>result:num [
<span id="L400" class="LineNr">400 </span>  <span class="Constant">local-scope</span>
<span id="L401" class="LineNr">401 </span>  <span class="Constant">load-inputs</span>
<span id="L402" class="LineNr">402 </span>  q:&amp;:@:_elem <span class="Special">&lt;-</span> get *chan, <span class="Constant">data:offset</span>
<span id="L403" class="LineNr">403 </span>  result <span class="Special">&lt;-</span> length *q
<span id="L404" class="LineNr">404 </span>]
<span id="L405" class="LineNr">405 </span>
<span id="L406" class="LineNr">406 </span><span class="SalientComment">## helpers for channels of characters in particular</span>
<span id="L407" class="LineNr">407 </span>
<span id="L408" class="LineNr">408 </span><span class="muRecipe">def</span> <a href='075channel.mu.html#L408'>buffer-lines</a> in:&amp;:<a href='075channel.mu.html#L43'>source</a>:char, buffered-out:&amp;:<a href='075channel.mu.html#L47'>sink</a>:char<span class="muRecipe"> -&gt; </span>buffered-out:&amp;:<a href='075channel.mu.html#L47'>sink</a>:char, in:&amp;:<a href='075channel.mu.html#L43'>source</a>:char [
<span id="L409" class="LineNr">409 </span>  <span class="Constant">local-scope</span>
<span id="L410" class="LineNr">410 </span>  <span class="Constant">load-inputs</span>
<span id="L411" class="LineNr">411 </span>  <span class="Comment"># repeat forever</span>
<span id="L412" class="LineNr">412 </span>  eof?:bool <span class="Special">&lt;-</span> copy <span class="Constant">0/false</span>
<span id="L413" class="LineNr">413 </span>  <span class="Delimiter">{</span>
<span id="L414" class="LineNr">414 </span>  <span class="Conceal">¦</span> line:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char <span class="Special">&lt;-</span> <a href='061text.mu.html#L125'>new-buffer</a><span class="Constant"> 30</span>
<span id="L415" class="LineNr">415 </span>  <span class="Conceal">¦</span> <span class="Comment"># read characters from 'in' until newline, copy into line</span>
<span id="L416" class="LineNr">416 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
<span id="L417" class="LineNr">417 </span><span class="Constant">  </span><span class="Conceal">¦</span><span class="Constant"> </span><span class="Conceal">¦</span><span class="Constant"> +next-character</span>
<span id="L418" class="LineNr">418 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> c:char, eof?:bool, in <span class="Special">&lt;-</span> read in
<span id="L419" class="LineNr">419 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> eof?
<span id="L420" class="LineNr">420 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># drop a character on backspace</span>
<span id="L421" class="LineNr">421 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
<span id="L422" class="LineNr">422 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># special-case: if it's a backspace</span>
<span id="L423" class="LineNr">423 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> backspace?:bool <span class="Special">&lt;-</span> equal c,<span class="Constant"> 8</span>
<span id="L424" class="LineNr">424 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> backspace?
<span id="L425" class="LineNr">425 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># drop previous character</span>
<span id="L426" class="LineNr">426 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">{</span>
<span id="L427" class="LineNr">427 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> buffer-length:num <span class="Special">&lt;-</span> get *line, <span class="Constant">length:offset</span>
<span id="L428" class="LineNr">428 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> buffer-empty?:bool <span class="Special">&lt;-</span> equal buffer-length,<span class="Constant"> 0</span>
<span id="L429" class="LineNr">429 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> buffer-empty?
<span id="L430" class="LineNr">430 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> buffer-length <span class="Special">&lt;-</span> subtract buffer-length,<span class="Constant"> 1</span>
<span id="L431" class="LineNr">431 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> *line <span class="Special">&lt;-</span> put *line, <span class="Constant">length:offset</span>, buffer-length
<span id="L432" class="LineNr">432 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L433" class="LineNr">433 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># and don't append this one</span>
<span id="L434" class="LineNr">434 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span> <span class="Constant">+next-character</span>
<span id="L435" class="LineNr">435 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L436" class="LineNr">436 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="Comment"># append anything else</span>
<span id="L437" class="LineNr">437 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> line <span class="Special">&lt;-</span> append line, c
<span id="L438" class="LineNr">438 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> line-done?:bool <span class="Special">&lt;-</span> equal c, <span class="Constant">10/newline</span>
<span id="L439" class="LineNr">439 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> line-done?
<span id="L440" class="LineNr">440 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span>
<span id="L441" class="LineNr">441 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L442" class="LineNr">442 </span>  <span class="Conceal">¦</span> <span class="Comment"># copy line into 'buffered-out'</span>
<span id="L443" class="LineNr">443 </span>  <span class="Conceal">¦</span> i:num <span class="Special">&lt;-</span> copy<span class="Constant"> 0</span>
<span id="L444" class="LineNr">444 </span>  <span class="Conceal">¦</span> line-contents:text <span class="Special">&lt;-</span> get *line, <span class="Constant">data:offset</span>
<span id="L445" class="LineNr">445 </span>  <span class="Conceal">¦</span> max:num <span class="Special">&lt;-</span> get *line, <span class="Constant">length:offset</span>
<span id="L446" class="LineNr">446 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
<span id="L447" class="LineNr">447 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> done?:bool <span class="Special">&lt;-</span> greater-or-equal i, max
<span id="L448" class="LineNr">448 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
<span id="L449" class="LineNr">449 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> c:char <span class="Special">&lt;-</span> index *line-contents, i
<span id="L450" class="LineNr">450 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> buffered-out <span class="Special">&lt;-</span> <a href='075channel.mu.html#L67'>write</a> buffered-out, c
<span id="L451" class="LineNr">451 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> i <span class="Special">&lt;-</span> add i,<span class="Constant"> 1</span>
<span id="L452" class="LineNr">452 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">loop</span>
<span id="L453" class="LineNr">453 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L454" class="LineNr">454 </span>  <span class="Conceal">¦</span> <span class="Delimiter">{</span>
<span id="L455" class="LineNr">455 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">break-unless</span> eof?
<span id="L456" class="LineNr">456 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> buffered-out <span class="Special">&lt;-</span> close buffered-out
<span id="L457" class="LineNr">457 </span>  <span class="Conceal">¦</span> <span class="Conceal">¦</span> <span class="muControl">return</span>
<span id="L458" class="LineNr">458 </span>  <span class="Conceal">¦</span> <span class="Delimiter">}</span>
<span id="L459" class="LineNr">459 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
<span id="L460" class="LineNr">460 </span>  <span class="Delimiter">}</span>
<span id="L461" class="LineNr">461 </span>]
<span id="L462" class="LineNr">462 </span>
<span id="L463" class="LineNr">463 </span><span class="muScenario">scenario</span> buffer-lines-blocks-until-newline [
<span id="L464" class="LineNr">464 </span>  run [
<span id="L465" class="LineNr">465 </span>  <span class="Conceal">¦</span> <span class="Constant">local-scope</span>
<span id="L466" class="LineNr">466 </span>  <span class="Conceal">¦</span> <a href='075channel.mu.html#L43'>source</a>:&amp;:<a href='075channel.mu.html#L43'>source</a>:char, <a href='075channel.mu.html#L47'>sink</a>:&amp;:<a href='075channel.mu.html#L47'>sink</a>:char <span class="Special">&lt;-</span> <a href='075channel.mu.html#L51'>new-channel</a> <span class="Constant">10/capacity</span>
<span id="L467" class="LineNr">467 </span>  <span class="Conceal">¦</span> _, buffered-stdin:&amp;:<a href='075channel.mu.html#L47'>sink</a>:char/buffered-stdin <span class="Special">&lt;-</span> <a href='075channel.mu.html#L51'>new-channel</a> <span class="Constant">10/capacity</span>
<span id="L468" class="LineNr">468 </span>  <span class="Conceal">¦</span> buffered-chan:&amp;:channel:char <span class="Special">&lt;-</span> get *buffered-stdin, <span class="Constant">chan:offset</span>
<span id="L469" class="LineNr">469 </span>  <span class="Conceal">¦</span> empty?:bool <span class="Special">&lt;-</span> <a href='075channel.mu.html#L370'>channel-empty?</a> buffered-chan
<span id="L470" class="LineNr">470 </span>  <span class="Conceal">¦</span> assert empty?, <span class="Constant">[ </span>
<span id="L471" class="LineNr">471 </span><span class="Constant">F buffer-lines-blocks-until-newline: channel should be empty after init]</span>
<span id="L472" class="LineNr">472 </span>  <span class="Conceal">¦</span> <span class="Comment"># buffer stdin into buffered-stdin, try to read from buffered-stdin</span>
<span id="L473" class="LineNr">473 </span>  <span class="Conceal">¦</span> buffer-routine:num <span class="Special">&lt;-</span> start-running <a href='075channel.mu.html#L408'>buffer-lines</a>, <a href='075channel.mu.html#L43'>source</a>, buffered-stdin
<span id="L474" class="LineNr">474 </span>  <span class="Conceal">¦</span> wait-for-routine-to-block buffer-routine
<span id="L475" class="LineNr">475 </span>  <span class="Conceal">¦</span> empty? <span class="Special">&lt;-</span> <a href='075channel.mu.html#L370'>channel-empty?</a> buffered-chan
<span id="L476" class="LineNr">476 </span>  <span class="Conceal">¦</span> assert empty?:bool, <span class="Constant">[ </span>
<span id="L477" class="LineNr">477 </span><span class="Constant">F buffer-lines-blocks-until-newline: channel should be empty after <a href='075channel.mu.html#L408'>buffer-lines</a> bring-up]</span>
<span id="L478" class="LineNr">478 </span>  <span class="Conceal">¦</span> <span class="Comment"># write 'a'</span>
<span id="L479" class="LineNr">479 </span>  <span class="Conceal">¦</span> <a href='075channel.mu.html#L47'>sink</a> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>, <span class="Constant">97/a</span>
<span id="L480" class="LineNr">480 </span>  <span class="Conceal">¦</span> restart buffer-routine
<span id="L481" class="LineNr">481 </span>  <span class="Conceal">¦</span> wait-for-routine-to-block buffer-routine
<span id="L482" class="LineNr">482 </span>  <span class="Conceal">¦</span> empty? <span class="Special">&lt;-</span> <a href='075channel.mu.html#L370'>channel-empty?</a> buffered-chan
<span id="L483" class="LineNr">483 </span>  <span class="Conceal">¦</span> assert empty?:bool, <span class="Constant">[ </span>
<span id="L484" class="LineNr">484 </span><span class="Constant">F buffer-lines-blocks-until-newline: channel should be empty after writing 'a']</span>
<span id="L485" class="LineNr">485 </span>  <span class="Conceal">¦</span> <span class="Comment"># write 'b'</span>
<span id="L486" class="LineNr">486 </span>  <span class="Conceal">¦</span> <a href='075channel.mu.html#L47'>sink</a> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>, <span class="Constant">98/b</span>
<span id="L487" class="LineNr">487 </span>  <span class="Conceal">¦</span> restart buffer-routine
<span id="L488" class="LineNr">488 </span>  <span class="Conceal">¦</span> wait-for-routine-to-block buffer-routine
<span id="L489" class="LineNr">489 </span>  <span class="Conceal">¦</span> empty? <span class="Special">&lt;-</span> <a href='075channel.mu.html#L370'>channel-empty?</a> buffered-chan
<span id="L490" class="LineNr">490 </span>  <span class="Conceal">¦</span> assert empty?:bool, <span class="Constant">[ </span>
<span id="L491" class="LineNr">491 </span><span class="Constant">F buffer-lines-blocks-until-newline: channel should be empty after writing 'b']</span>
<span id="L492" class="LineNr">492 </span>  <span class="Conceal">¦</span> <span class="Comment"># write newline</span>
<span id="L493" class="LineNr">493 </span>  <span class="Conceal">¦</span> <a href='075channel.mu.html#L47'>sink</a> <span class="Special">&lt;-</span> <a href='075channel.mu.html#L67'>write</a> <a href='075channel.mu.html#L47'>sink</a>, <span class="Constant">10/newline</span>
<span id="L494" class="LineNr">494 </span>  <span class="Conceal">¦</span> restart buffer-routine
<span id="L495" class="LineNr">495 </span>  <span class="Conceal">¦</span> wait-for-routine-to-block buffer-routine
<span id="L496" class="LineNr">496 </span>  <span class="Conceal">¦</span> empty? <span class="Special">&lt;-</span> <a href='075channel.mu.html#L370'>channel-empty?</a> buffered-chan
<span id="L497" class="LineNr">497 </span>  <span class="Conceal">¦</span> data-emitted?:bool <span class="Special">&lt;-</span> not empty?
<span id="L498" class="LineNr">498 </span>  <span class="Conceal">¦</span> assert data-emitted?, <span class="Constant">[ </span>
<span id="L499" class="LineNr">499 </span><span class="Constant">F buffer-lines-blocks-until-newline: channel should contain data after writing newline]</span>
<span id="L500" class="LineNr">500 </span>  <span class="Conceal">¦</span> trace<span class="Constant"> 1</span>, <span class="Constant">[test]</span>, <span class="Constant">[reached end]</span>
<span id="L501" class="LineNr">501 </span>  ]
<span id="L502" class="LineNr">502 </span>  trace-should-contain [
<span id="L503" class="LineNr">503 </span>  <span class="Conceal">¦</span> test: reached end
<span id="L504" class="LineNr">504 </span>  ]
<span id="L505" class="LineNr">505 </span>]
<span id="L506" class="LineNr">506 </span>
<span id="L507" class="LineNr">507 </span><span class="muRecipe">def</span> <a href='075channel.mu.html#L507'>drain</a> <a href='075channel.mu.html#L43'>source</a>:&amp;:<a href='075channel.mu.html#L43'>source</a>:char<span class="muRecipe"> -&gt; </span>result:text, <a href='075channel.mu.html#L43'>source</a>:&amp;:<a href='075channel.mu.html#L43'>source</a>:char [
<span id="L508" class="LineNr">508 </span>  <span class="Constant">local-scope</span>
<span id="L509" class="LineNr">509 </span>  <span class="Constant">load-inputs</span>
<span id="L510" class="LineNr">510 </span>  buf:&amp;:<a href='061text.mu.html#L120'>buffer</a>:char <span class="Special">&lt;-</span> <a href='061text.mu.html#L125'>new-buffer</a><span class="Constant"> 30</span>
<span id="L511" class="LineNr">511 </span>  <span class="Delimiter">{</span>
<span id="L512" class="LineNr">512 </span>  <span class="Conceal">¦</span> c:char, done?:bool <span class="Special">&lt;-</span> read <a href='075channel.mu.html#L43'>source</a>
<span id="L513" class="LineNr">513 </span>  <span class="Conceal">¦</span> <span class="muControl">break-if</span> done?
<span id="L514" class="LineNr">514 </span>  <span class="Conceal">¦</span> buf <span class="Special">&lt;-</span> append buf, c
<span id="L515" class="LineNr">515 </span>  <span class="Conceal">¦</span> <span class="muControl">loop</span>
<span id="L516" class="LineNr">516 </span>  <span class="Delimiter">}</span>
<span id="L517" class="LineNr">517 </span>  result <span class="Special">&lt;-</span> <a href='061text.mu.html#L338'>buffer-to-array</a> buf
<span id="L518" class="LineNr">518 </span>]
</pre>
</body>
</html>
<!-- vim: set foldmethod=manual : -->