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annotate lib/js/urweb.js @ 846:0d30e6338c65

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Some standard library reorgs and additions; handle mutual datatypes better in Specialize
author Adam Chlipala <adamc@hcoop.net>
date Tue, 09 Jun 2009 18:11:59 -0400
parents 44c2c089ca15
children 0f7e2cca6d9b
rev   line source
adamc@692 1 // Lists
adamc@692 2
adamc@580 3 function cons(v, ls) {
adamc@690 4 return { next : ls, data : v };
adamc@690 5 }
adamc@690 6 function concat(ls1, ls2) {
adamc@690 7 return (ls1 ? cons(ls1.data, concat(ls1.next, ls2)) : ls2);
adamc@690 8 }
adamc@690 9 function member(x, ls) {
adamc@690 10 for (; ls; ls = ls.next)
adamc@690 11 if (ls.data == x)
adamc@690 12 return true;
adamc@690 13 return false;
adamc@690 14 }
adamc@690 15 function remove(x, ls) {
adamc@690 16 return (ls ? (ls.data == x ? ls.next : cons(ls.data, remove(x, ls.next))) : null);
adamc@690 17 }
adamc@690 18 function union(ls1, ls2) {
adamc@690 19 return (ls1 ? (member(ls1.data, ls2) ? union(ls1.next, ls2) : cons(ls1.data, union(ls1.next, ls2))) : ls2);
adamc@580 20 }
adamc@703 21 function length(ls) {
adamc@703 22 return (ls ? 1 + length(ls.next) : 0);
adamc@703 23 }
adamc@670 24
adamc@690 25
adamc@729 26 // Error handling
adamc@729 27
adamc@729 28 function whine(msg) {
adamc@729 29 alert(msg);
adamc@729 30 throw msg;
adamc@729 31 }
adamc@729 32
adamc@810 33 function pf(loc) {
adamc@835 34 throw ("Pattern match failure (" + loc + ")");
adamc@729 35 }
adamc@729 36
adamc@798 37 function runHandlers(kind, ls, arg) {
adamc@798 38 if (ls == null)
adamc@798 39 alert(kind + ": " + arg);
adamc@729 40 for (; ls; ls = ls.next)
adamc@729 41 try {
adamc@729 42 ls.data(arg)(null);
adamc@729 43 } catch (v) { }
adamc@729 44 }
adamc@729 45
adamc@729 46 var errorHandlers = null;
adamc@729 47
adamc@729 48 function onError(f) {
adamc@729 49 errorHandlers = cons(f, errorHandlers);
adamc@729 50 }
adamc@729 51
adamc@729 52 function er(s) {
adamc@798 53 runHandlers("Error", errorHandlers, s);
adamc@729 54 throw {uw_error: s};
adamc@729 55 }
adamc@729 56
adamc@729 57 var failHandlers = null;
adamc@729 58
adamc@729 59 function onFail(f) {
adamc@729 60 failHandlers = cons(f, failHandlers);
adamc@729 61 }
adamc@729 62
adamc@729 63 function doExn(v) {
adamc@729 64 if (v == null || v.uw_error == null) {
adamc@729 65 var s = (v == null ? "null" : v.toString());
adamc@798 66 runHandlers("Fail", failHandlers, s);
adamc@729 67 }
adamc@729 68 }
adamc@729 69
adamc@729 70 var disconnectHandlers = null;
adamc@729 71
adamc@729 72 function onDisconnect(f) {
adamc@729 73 disconnectHandlers = cons(function (_){return f}, disconnectHandlers);
adamc@729 74 }
adamc@729 75
adamc@729 76 function discon() {
adamc@798 77 runHandlers("Disconnect", disconnectHandlers, null);
adamc@729 78 }
adamc@729 79
adamc@729 80 var connectHandlers = null;
adamc@729 81
adamc@729 82 function onConnectFail(f) {
adamc@729 83 connectHandlers = cons(function (_){return f}, connectHandlers);
adamc@729 84 }
adamc@729 85
adamc@729 86 function conn() {
adamc@798 87 runHandlers("Connect", connectHandlers, null);
adamc@729 88 }
adamc@729 89
adamc@729 90 var serverHandlers = null;
adamc@729 91
adamc@729 92 function onServerError(f) {
adamc@729 93 serverHandlers = cons(f, serverHandlers);
adamc@729 94 }
adamc@729 95
adamc@729 96 function servErr(s) {
adamc@824 97 window.setTimeout(function () { runHandlers("Server", serverHandlers, s); }, 0);
adamc@729 98 }
adamc@729 99
adamc@729 100
adamc@692 101 // Embedding closures in XML strings
adamc@692 102
adamc@693 103 function cs(f) {
adamc@693 104 return {closure: f};
adamc@693 105 }
adamc@693 106
adamc@693 107 function isWeird(v) {
adamc@693 108 return v.closure != null || v.cat1 != null;
adamc@693 109 }
adamc@693 110
adamc@692 111 function cat(s1, s2) {
adamc@693 112 if (isWeird(s1) || isWeird(s2))
adamc@693 113 return {cat1: s1, cat2: s2};
adamc@693 114 else
adamc@692 115 return s1 + s2;
adamc@692 116 }
adamc@692 117
adamc@692 118 var closures = [];
adamc@703 119 var freeClosures = null;
adamc@692 120
adamc@692 121 function newClosure(f) {
adamc@703 122 var n;
adamc@703 123 if (freeClosures == null) {
adamc@703 124 n = closures.length;
adamc@703 125 } else {
adamc@703 126 n = freeClosures.data;
adamc@703 127 freeClosures = freeClosures.next;
adamc@703 128 }
adamc@692 129 closures[n] = f;
adamc@692 130 return n;
adamc@692 131 }
adamc@692 132
adamc@703 133 function freeClosure(n) {
adamc@703 134 closures[n] = null;
adamc@703 135 freeClosures = cons(n, freeClosures);
adamc@703 136 }
adamc@703 137
adamc@692 138 function cr(n) {
adamc@692 139 return closures[n]();
adamc@692 140 }
adamc@692 141
adamc@703 142 function flatten(cls, tr) {
adamc@693 143 if (tr.cat1 != null)
adamc@703 144 return flatten(cls, tr.cat1) + flatten(cls, tr.cat2);
adamc@703 145 else if (tr.closure != null) {
adamc@703 146 var cl = newClosure(tr.closure);
adamc@703 147 cls.v = cons(cl, cls.v);
adamc@703 148 return "cr(" + cl + ")";
adamc@703 149 } else
adamc@692 150 return tr;
adamc@692 151 }
adamc@692 152
adamc@728 153 function flattenLocal(s) {
adamc@728 154 var cls = {v : null};
adamc@728 155 var r = flatten(cls, s);
adamc@728 156 for (cl = cls.v; cl != null; cl = cl.next)
adamc@728 157 freeClosure(cl.data);
adamc@728 158 return r;
adamc@728 159 }
adamc@728 160
adamc@692 161
adamc@692 162
adamc@692 163 // Dynamic tree management
adamc@692 164
adamc@690 165 function populate(node) {
adamc@690 166 var s = node.signal;
adamc@690 167 var oldSources = node.sources;
adamc@729 168 try {
adamc@729 169 var sr = s();
adamc@729 170 var newSources = sr.sources;
adamc@690 171
adamc@729 172 for (var sp = oldSources; sp; sp = sp.next)
adamc@729 173 if (!member(sp.data, newSources))
adamc@729 174 sp.data.dyns = remove(node, sp.data.dyns);
adamc@690 175
adamc@729 176 for (var sp = newSources; sp; sp = sp.next)
adamc@729 177 if (!member(sp.data, oldSources))
adamc@729 178 sp.data.dyns = cons(node, sp.data.dyns);
adamc@690 179
adamc@729 180 node.sources = newSources;
adamc@729 181 node.recreate(sr.data);
adamc@729 182 } catch (v) {
adamc@729 183 doExn(v);
adamc@729 184 }
adamc@579 185 }
adamc@574 186
adamc@580 187 function sc(v) {
adamc@690 188 return {data : v, dyns : null};
adamc@580 189 }
adamc@580 190 function sv(s, v) {
adamc@690 191 s.data = v;
adamc@690 192 for (var ls = s.dyns; ls; ls = ls.next)
adamc@690 193 if (!ls.dead)
adamc@690 194 populate(ls.data);
adamc@580 195 }
adamc@601 196 function sg(s) {
adamc@690 197 return s.data;
adamc@601 198 }
adamc@579 199
adamc@580 200 function ss(s) {
adamc@690 201 return function() { return {sources : cons(s, null), data : s.data } };
adamc@580 202 }
adamc@580 203 function sr(v) {
adamc@690 204 return function() { return {sources : null, data : v } };
adamc@580 205 }
adamc@580 206 function sb(x,y) {
adamc@690 207 return function() {
adamc@690 208 var xr = x();
adamc@690 209 var yr = y(xr.data)();
adamc@690 210 return {sources : union(xr.sources, yr.sources), data : yr.data};
adamc@690 211 };
adamc@580 212 }
adamc@841 213 function scur(s) {
adamc@841 214 return s().data;
adamc@841 215 }
adamc@571 216
adamc@604 217 function lastParent() {
adamc@604 218 var pos = document;
adamc@604 219
adamc@600 220 while (pos.lastChild && pos.lastChild.nodeType == 1)
adamc@600 221 pos = pos.lastChild;
adamc@600 222
adamc@600 223 return pos.parentNode;
adamc@600 224 }
adamc@600 225
adamc@604 226 function addNode(node) {
adamc@604 227 if (thisScript) {
adamc@604 228 thisScript.parentNode.appendChild(node);
adamc@604 229 thisScript.parentNode.removeChild(thisScript);
adamc@604 230 } else
adamc@604 231 lastParent().appendChild(node);
adamc@603 232 }
adamc@603 233
adamc@812 234 function setHTML(html) {
adamc@812 235 var x = document.createElement("span");
adamc@812 236 x.dead = false;
adamc@812 237 x.signal = null;
adamc@812 238 x.sources = null;
adamc@812 239 x.closures = null;
adamc@812 240 x.innerHTML = html;
adamc@812 241 addNode(x);
adamc@812 242 runScripts(x);
adamc@812 243 }
adamc@812 244
adamc@690 245 var thisScript = null;
adamc@690 246
adamc@604 247 function runScripts(node) {
adamc@604 248 var savedScript = thisScript;
adamc@603 249
adamc@692 250 var scripts = node.getElementsByTagName("script"), scriptsCopy = [];
adamc@604 251 var len = scripts.length;
adamc@646 252 for (var i = 0; i < len; ++i)
adamc@646 253 scriptsCopy[i] = scripts[i];
adamc@604 254 for (var i = 0; i < len; ++i) {
adamc@646 255 thisScript = scriptsCopy[i];
adamc@729 256 try {
adamc@729 257 eval(thisScript.textContent);
adamc@729 258 } catch (v) {
adamc@729 259 doExn(v);
adamc@729 260 }
adamc@604 261 }
adamc@604 262
adamc@604 263 thisScript = savedScript;
adamc@603 264 }
adamc@603 265
adamc@603 266
adamc@692 267 // Dynamic tree entry points
adamc@692 268
adamc@692 269 var dynDepth = 0;
adamc@692 270
adamc@571 271 function dyn(s) {
adamc@571 272 var x = document.createElement("span");
adamc@690 273 x.dead = false;
adamc@690 274 x.signal = s;
adamc@690 275 x.sources = null;
adamc@703 276 x.closures = null;
adamc@690 277 x.recreate = function(v) {
adamc@703 278 for (var ls = x.closures; ls; ls = ls.next)
adamc@703 279 freeClosure(ls.data);
adamc@692 280
adamc@690 281 var spans = x.getElementsByTagName("span");
adamc@690 282 for (var i = 0; i < spans.length; ++i) {
adamc@690 283 var span = spans[i];
adamc@690 284 span.dead = true;
adamc@690 285 for (var ls = span.sources; ls; ls = ls.next)
adamc@690 286 ls.data.dyns = remove(span, ls.data.dyns);
adamc@703 287 for (var ls = span.closures; ls; ls = ls.next)
adamc@703 288 freeClosure(ls.data);
adamc@690 289 }
adamc@690 290
adamc@703 291 var cls = {v : null};
adamc@703 292 x.innerHTML = flatten(cls, v);
adamc@703 293 x.closures = cls.v;
adamc@690 294 runScripts(x);
adamc@690 295 };
adamc@703 296 addNode(x);
adamc@690 297 populate(x);
adamc@571 298 }
adamc@582 299
adamc@817 300 function input(t, s, recreate) {
adamc@598 301 var x = document.createElement(t);
adamc@690 302 x.dead = false;
adamc@690 303 x.signal = ss(s);
adamc@690 304 x.sources = null;
adamc@817 305 x.recreate = recreate(x);
adamc@690 306 populate(x);
adamc@604 307 addNode(x);
adamc@816 308
adamc@816 309 return x;
adamc@816 310 }
adamc@816 311
adamc@816 312 function inp(s) {
adamc@817 313 var x = input("input", s, function(x) { return function(v) { if (x.value != v) x.value = v; }; });
adamc@816 314 x.value = s.data;
adamc@816 315 x.onkeyup = function() { sv(s, x.value) };
adamc@816 316
adamc@816 317 return x;
adamc@816 318 }
adamc@816 319
adamc@816 320 function sel(s, content) {
adamc@817 321 var x = input("select", s, function(x) { return function(v) { if (x.value != v) x.value = v; }; });
adamc@816 322 x.innerHTML = content;
adamc@816 323 x.value = s.data;
adamc@835 324 if (x.value != s.data)
adamc@835 325 sv(s, x.value);
adamc@816 326 x.onchange = function() { sv(s, x.value) };
adamc@797 327
adamc@835 328
adamc@606 329 return x;
adamc@598 330 }
adamc@598 331
adamc@817 332 function chk(s) {
adamc@817 333 var x = input("input", s, function(x) { return function(v) { if (x.checked != v) x.checked = v; }; });
adamc@817 334 x.type = "checkbox";
adamc@817 335 x.checked = s.data;
adamc@817 336 x.onchange = function() { sv(s, x.checked) };
adamc@817 337
adamc@817 338 return x;
adamc@817 339 }
adamc@817 340
adamc@800 341 function addOnChange(x, f) {
adamc@800 342 var old = x.onchange;
adamc@800 343 x.onchange = function() { old(); f (); };
adamc@800 344 }
adamc@800 345
adamc@692 346
adamc@692 347 // Basic string operations
adamc@692 348
adamc@597 349 function eh(x) {
adamc@800 350 if (x == null)
adamc@800 351 return "NULL";
adamc@800 352 else
adamc@800 353 return x.split("&").join("&amp;").split("<").join("&lt;").split(">").join("&gt;");
adamc@597 354 }
adamc@597 355
adamc@582 356 function ts(x) { return x.toString() }
adamc@586 357 function bs(b) { return (b ? "True" : "False") }
adamc@586 358
adamc@828 359 function sub(s, i) { return s[i]; }
adamc@828 360 function suf(s, i) { return s.substring(i); }
adamc@828 361 function slen(s) { return s.length; }
adamc@829 362 function sidx(s, ch) {
adamc@829 363 var r = s.indexOf(ch);
adamc@829 364 if (r == -1)
adamc@829 365 return null;
adamc@829 366 else
adamc@829 367 return r;
adamc@829 368 }
adamc@831 369 function sspn(s, chs) {
adamc@831 370 for (var i = 0; i < s.length; ++i)
adamc@831 371 if (chs.indexOf(s[i]) != -1)
adamc@831 372 return i;
adamc@831 373
adamc@831 374 return null;
adamc@831 375 }
adamc@829 376 function schr(s, ch) {
adamc@829 377 var r = s.indexOf(ch);
adamc@829 378 if (r == -1)
adamc@829 379 return null;
adamc@829 380 else
adamc@829 381 return s.substring(r);
adamc@829 382 }
adamc@829 383 function ssub(s, start, len) {
adamc@829 384 return s.substring(start, start+len);
adamc@829 385 }
adamc@821 386
adamc@649 387 function pi(s) {
adamc@649 388 var r = parseInt(s);
adamc@649 389 if (r.toString() == s)
adamc@649 390 return r;
adamc@649 391 else
adamc@729 392 er("Can't parse int: " + s);
adamc@649 393 }
adamc@649 394
adamc@649 395 function pfl(s) {
adamc@649 396 var r = parseFloat(s);
adamc@649 397 if (r.toString() == s)
adamc@649 398 return r;
adamc@649 399 else
adamc@729 400 er("Can't parse float: " + s);
adamc@649 401 }
adamc@649 402
adamc@838 403 function pio(s) {
adamc@838 404 var r = parseInt(s);
adamc@838 405 if (r.toString() == s)
adamc@838 406 return r;
adamc@838 407 else
adamc@838 408 return null;
adamc@838 409 }
adamc@838 410
adamc@838 411 function pflo(s) {
adamc@838 412 var r = parseFloat(s);
adamc@838 413 if (r.toString() == s)
adamc@838 414 return r;
adamc@838 415 else
adamc@838 416 return null;
adamc@838 417 }
adamc@838 418
adamc@692 419 function uf(s) {
adamc@692 420 return escape(s).replace(new RegExp ("/", "g"), "%2F");
adamc@691 421 }
adamc@691 422
adamc@692 423 function uu(s) {
adamc@692 424 return unescape(s).replace(new RegExp ("\\+", "g"), " ");
adamc@692 425 }
adamc@692 426
adamc@692 427
adamc@603 428
adamc@692 429 // Remote calls
adamc@609 430
adamc@703 431 var client_id = null;
adamc@668 432 var client_pass = 0;
adamc@668 433 var url_prefix = "/";
adamc@673 434 var timeout = 60;
adamc@668 435
adamc@668 436 function getXHR(uri)
adamc@609 437 {
adamc@609 438 try {
adamc@609 439 return new XMLHttpRequest();
adamc@609 440 } catch (e) {
adamc@609 441 try {
adamc@609 442 return new ActiveXObject("Msxml2.XMLHTTP");
adamc@609 443 } catch (e) {
adamc@609 444 try {
adamc@609 445 return new ActiveXObject("Microsoft.XMLHTTP");
adamc@609 446 } catch (e) {
adamc@609 447 throw "Your browser doesn't seem to support AJAX.";
adamc@609 448 }
adamc@609 449 }
adamc@609 450 }
adamc@609 451 }
adamc@609 452
adamc@736 453 var sig = null;
adamc@736 454
adamc@736 455 function requestUri(xhr, uri, needsSig) {
adamc@668 456 xhr.open("GET", uri, true);
adamc@668 457
adamc@703 458 if (client_id != null) {
adamc@668 459 xhr.setRequestHeader("UrWeb-Client", client_id.toString());
adamc@668 460 xhr.setRequestHeader("UrWeb-Pass", client_pass.toString());
adamc@668 461 }
adamc@668 462
adamc@736 463 if (needsSig) {
adamc@736 464 if (sig == null)
adamc@736 465 whine("Missing cookie signature!");
adamc@736 466
adamc@736 467 xhr.setRequestHeader("UrWeb-Sig", sig);
adamc@736 468 }
adamc@736 469
adamc@668 470 xhr.send(null);
adamc@668 471 }
adamc@668 472
adamc@736 473 function rc(uri, parse, k, needsSig) {
adamc@728 474 uri = flattenLocal(uri);
adamc@609 475 var xhr = getXHR();
adamc@609 476
adamc@609 477 xhr.onreadystatechange = function() {
adamc@612 478 if (xhr.readyState == 4) {
adamc@612 479 var isok = false;
adamc@612 480
adamc@612 481 try {
adamc@612 482 if (xhr.status == 200)
adamc@612 483 isok = true;
adamc@612 484 } catch (e) { }
adamc@612 485
adamc@729 486 if (isok) {
adamc@729 487 try {
adamc@729 488 k(parse(xhr.responseText));
adamc@729 489 } catch (v) {
adamc@729 490 doExn(v);
adamc@729 491 }
adamc@729 492 } else {
adamc@729 493 conn();
adamc@649 494 }
adamc@612 495 }
adamc@609 496 };
adamc@609 497
adamc@736 498 requestUri(xhr, uri, needsSig);
adamc@609 499 }
adamc@667 500
adamc@667 501 function path_join(s1, s2) {
adamc@667 502 if (s1.length > 0 && s1[s1.length-1] == '/')
adamc@667 503 return s1 + s2;
adamc@667 504 else
adamc@667 505 return s1 + "/" + s2;
adamc@667 506 }
adamc@667 507
adamc@670 508 var channels = [];
adamc@670 509
adamc@670 510 function newQueue() {
adamc@670 511 return { front : null, back : null };
adamc@670 512 }
adamc@670 513 function enqueue(q, v) {
adamc@670 514 if (q.front == null) {
adamc@670 515 q.front = cons(v, null);
adamc@670 516 q.back = q.front;
adamc@670 517 } else {
adamc@670 518 var node = cons(v, null);
adamc@690 519 q.back.next = node;
adamc@670 520 q.back = node;
adamc@670 521 }
adamc@670 522 }
adamc@670 523 function dequeue(q) {
adamc@670 524 if (q.front == null)
adamc@670 525 return null;
adamc@670 526 else {
adamc@690 527 var r = q.front.data;
adamc@690 528 q.front = q.front.next;
adamc@670 529 if (q.front == null)
adamc@670 530 q.back = null;
adamc@670 531 return r;
adamc@670 532 }
adamc@670 533 }
adamc@670 534
adamc@670 535 function newChannel() {
adamc@670 536 return { msgs : newQueue(), listeners : newQueue() };
adamc@670 537 }
adamc@670 538
adamc@667 539 function listener() {
adamc@668 540 var uri = path_join(url_prefix, ".msgs");
adamc@667 541 var xhr = getXHR();
adamc@673 542 var tid, orsc, onTimeout;
adamc@673 543
adamc@673 544 var connect = function () {
adamc@673 545 xhr.onreadystatechange = orsc;
adamc@673 546 tid = window.setTimeout(onTimeout, timeout * 500);
adamc@736 547 requestUri(xhr, uri, false);
adamc@673 548 }
adamc@673 549
adamc@673 550 orsc = function() {
adamc@667 551 if (xhr.readyState == 4) {
adamc@673 552 window.clearTimeout(tid);
adamc@673 553
adamc@667 554 var isok = false;
adamc@667 555
adamc@667 556 try {
adamc@667 557 if (xhr.status == 200)
adamc@667 558 isok = true;
adamc@667 559 } catch (e) { }
adamc@667 560
adamc@668 561 if (isok) {
adamc@669 562 var lines = xhr.responseText.split("\n");
adamc@729 563 if (lines.length < 2) {
adamc@729 564 discon();
adamc@729 565 return;
adamc@729 566 }
adamc@669 567
adamc@669 568 for (var i = 0; i+1 < lines.length; i += 2) {
adamc@670 569 var chn = lines[i];
adamc@670 570 var msg = lines[i+1];
adamc@670 571
adamc@670 572 if (chn < 0)
adamc@670 573 whine("Out-of-bounds channel in message from remote server");
adamc@670 574
adamc@670 575 var ch;
adamc@670 576
adamc@670 577 if (chn >= channels.length || channels[chn] == null) {
adamc@670 578 ch = newChannel();
adamc@670 579 channels[chn] = ch;
adamc@670 580 } else
adamc@670 581 ch = channels[chn];
adamc@670 582
adamc@670 583 var listener = dequeue(ch.listeners);
adamc@670 584 if (listener == null) {
adamc@670 585 enqueue(ch.msgs, msg);
adamc@670 586 } else {
adamc@728 587 try {
adamc@728 588 listener(msg);
adamc@728 589 } catch (v) {
adamc@728 590 doExn(v);
adamc@728 591 }
adamc@670 592 }
adamc@669 593 }
adamc@669 594
adamc@673 595 connect();
adamc@668 596 }
adamc@667 597 else {
adamc@729 598 try {
adamc@824 599 if (xhr.status != 0)
adamc@824 600 servErr("Error querying remote server for messages: " + xhr.status);
adamc@736 601 } catch (e) { servErr("Error querying remote server for messages"); }
adamc@667 602 }
adamc@667 603 }
adamc@667 604 };
adamc@667 605
adamc@673 606 onTimeout = function() {
adamc@673 607 xhr.abort();
adamc@673 608 connect();
adamc@673 609 };
adamc@673 610
adamc@673 611 connect();
adamc@667 612 }
adamc@670 613
adamc@670 614 function rv(chn, parse, k) {
adamc@682 615 if (chn == null)
adamc@682 616 return;
adamc@682 617
adamc@670 618 if (chn < 0)
adamc@670 619 whine("Out-of-bounds channel receive");
adamc@670 620
adamc@670 621 var ch;
adamc@670 622
adamc@670 623 if (chn >= channels.length || channels[chn] == null) {
adamc@670 624 ch = newChannel();
adamc@670 625 channels[chn] = ch;
adamc@670 626 } else
adamc@670 627 ch = channels[chn];
adamc@670 628
adamc@670 629 var msg = dequeue(ch.msgs);
adamc@670 630 if (msg == null) {
adamc@670 631 enqueue(ch.listeners, function(msg) { k(parse(msg))(null); });
adamc@670 632 } else {
adamc@728 633 try {
adamc@728 634 k(parse(msg))(null);
adamc@728 635 } catch (v) {
adamc@728 636 doExn(v);
adamc@728 637 }
adamc@670 638 }
adamc@670 639 }
adamc@693 640
adamc@693 641
adamc@693 642 // App-specific code
adamc@693 643