/jsmeter/parse.js
JavaScript | 782 lines | 682 code | 60 blank | 40 comment | 114 complexity | f6beebda37eb0020a7b12cc969525cc6 MD5 | raw file
1// parse.js 2// Parser for Simplified JavaScript written in Simplified JavaScript 3// From Top Down Operator Precedence 4// http://javascript.crockford.com/tdop/index.html 5// Douglas Crockford 6// 2008-07-07 7 8exports.make_parse = function () { 9 var scope; 10 var symbol_table = {}; 11 var token; 12 var tokens; 13 var token_nr; 14 var nextComments = [ ]; 15 16 var itself = function () { 17 return this; 18 }; 19 20 var original_scope = { 21 define: function (n) { 22 var t = this.def[n.value]; 23 /*if (typeof t === "object") { 24 n.error(t.reserved ? "Already reserved." : "Already defined."); 25 }*/ 26 this.def[n.value] = n; 27 n.reserved = false; 28 n.nud = itself; 29 n.led = null; 30 n.std = null; 31 n.lbp = 0; 32 n.scope = scope; 33 return n; 34 }, 35 find: function (n) { 36 var e = this, o; 37 while (true) { 38 o = e.def[n]; 39 if (o && o.nud) { 40 return o; 41 } 42 e = e.parent; 43 if (!e) { 44 if (!symbol_table.hasOwnProperty(n)) { 45 var s = symbol(n); 46 s.nud = function() { 47 return this; 48 } 49 } 50 return symbol_table[n]; 51 } 52 } 53 }, 54 pop: function () { 55 scope = this.parent; 56 }, 57 reserve: function (n) { 58 if (n.arity !== "name" || n.reserved) { 59 return; 60 } 61 var t = this.def[n.value]; 62 if (t) { 63 if (t.reserved) { 64 return; 65 } 66 if (t.arity === "name") { 67 //n.error("Already defined."); 68 } 69 } 70 this.def[n.value] = n; 71 n.reserved = true; 72 } 73 }; 74 75 var new_scope = function () { 76 var s = scope; 77 scope = Object.create(original_scope); 78 scope.def = {}; 79 scope.parent = s; 80 return scope; 81 }; 82 83 var advance = function (id) { 84 var a, o, t, v, cl, cli; 85 if (id && token.id !== id) { 86 token.error("Expected '" + id + "'."); 87 } 88 if (token_nr >= tokens.length) { 89 token = symbol_table["(end)"]; 90 return; 91 } 92 t = tokens[token_nr]; 93 token_nr += 1; 94 v = t.value; 95 a = t.type; 96 if (a === "name") { 97 o = scope.find(v); 98 } else if (a === "operator") { 99 o = symbol_table[v]; 100 if (!o) { 101 t.error("Unknown operator."); 102 } 103 } else if (a === "string" || a === "number" || a === "regexp" || a === "regexpops") { 104 o = symbol_table["(literal)"]; 105 a = "literal"; 106 } else if (a === "comment") { 107 o = symbol_table["(comment)"]; 108 } else { 109 t.error("Unexpected token."); 110 } 111 token = Object.create(o); 112 token.from = t.from; 113 token.to = t.to; 114 token.line = t.line; 115 token.value = v; 116 token.arity = a; 117 //window.status = JSON.stringify(token); 118 119 if (token.arity === "comment") { 120 cl = v.split(/\n/g); 121 for (cli=0; cli<cl.length; cli++) { 122 nextComments.push(cl[cli]); 123 } 124 advance(); 125 } 126 127 return token; 128 }; 129 130 var expression = function (rbp) { 131 var left; 132 var t = token; 133 advance(); 134 left = t.nud(); 135 while (rbp < token.lbp) { 136 t = token; 137 advance(); 138 left = t.led(left); 139 } 140 if (left) { 141 left.comments = nextComments; 142 nextComments = [ ]; 143 } 144 return left; 145 }; 146 147 var statement = function () { 148 var n = token, v; 149 150 if (n.std) { 151 advance(); 152 scope.reserve(n); 153 return n.std(); 154 } 155 v = expression(0); 156 /*if (!v.assignment && 157 v.id !== "(" && 158 v.id!== "++" && 159 v.id!== "--" && 160 v.value!=="use strict" && 161 v.id!=="typeof") { 162 v.error("Bad expression statement."); 163 }*/ 164 /*if (v.assignment && v.arity==="function") { 165 advance(); 166 } else { 167 advance(";"); 168 }*/ 169 if (token.id===";") { 170 advance(";"); 171 } 172 if (v) { 173 v.comments = nextComments; 174 nextComments = [ ]; 175 } 176 return v; 177 }; 178 179 var statements = function () { 180 var a = [], s; 181 while (true) { 182 if (token.id === "}" || token.id === "(end)") { 183 break; 184 } 185 s = statement(); 186 if (s) { 187 a.push(s); 188 } 189 } 190 return a.length === 0 ? null : a.length === 1 ? a[0] : a; 191 }; 192 193 var block = function () { 194 var t = token; 195 advance("{"); 196 return t.std(); 197 }; 198 199 var original_symbol = { 200 nud: function () { 201 //this.error("Undefined."); 202 }, 203 led: function (left) { 204 this.error("Missing operator."); 205 } 206 }; 207 208 var symbol = function (id, bp) { 209 var s = symbol_table[id]; 210 bp = bp || 0; 211 if (s) { 212 if (bp >= s.lbp) { 213 s.lbp = bp; 214 } 215 } else { 216 s = Object.create(original_symbol); 217 s.id = s.value = id; 218 s.lbp = bp; 219 symbol_table[id] = s; 220 } 221 return s; 222 }; 223 224 var constant = function (s, v) { 225 var x = symbol(s); 226 x.nud = function () { 227 scope.reserve(this); 228 this.value = symbol_table[this.id].value; 229 this.arity = "literal"; 230 return this; 231 }; 232 x.value = v; 233 return x; 234 }; 235 236 var infix = function (id, bp, led) { 237 var s = symbol(id, bp); 238 s.led = led || function (left) { 239 this.first = left; 240 this.second = expression(bp); 241 this.arity = "binary"; 242 return this; 243 }; 244 return s; 245 }; 246 247 var infixr = function (id, bp, led) { 248 var s = symbol(id, bp); 249 s.led = led || function (left) { 250 this.first = left; 251 this.second = expression(bp - 1); 252 this.arity = "binary"; 253 return this; 254 }; 255 return s; 256 }; 257 258 var assignment = function (id) { 259 return infixr(id, 10, function (left) { 260 if (left.id !== "." && left.id !== "[" && left.arity !== "name") { 261 left.error("Bad lvalue."); 262 } 263 this.first = left; 264 this.second = expression(9); 265 this.assignment = true; 266 this.arity = "binary"; 267 if (token.id===",") { 268 advance(","); 269 } 270 return this; 271 }); 272 }; 273 274 var prefix = function (id, nud) { 275 var s = symbol(id); 276 s.nud = nud || function () { 277 scope.reserve(this); 278 this.first = expression(70); 279 this.arity = "unary"; 280 return this; 281 }; 282 return s; 283 }; 284 285 var stmt = function (s, f) { 286 var x = symbol(s); 287 x.std = f; 288 return x; 289 }; 290 291 symbol("(end)"); 292 symbol("(name)"); 293 symbol(":"); 294 symbol(";"); 295 symbol(")"); 296 symbol("]"); 297 symbol("}"); 298 symbol(","); 299 symbol("else"); 300 301 constant("true", true); 302 constant("false", false); 303 constant("null", null); 304 constant("pi", 3.141592653589793); 305 constant("Object", {}); 306 constant("Array", []); 307 constant("Date", "Date"); 308 constant("Math", "Math"); 309 310 symbol("(literal)").nud = itself; 311 symbol("(comment)"); 312 313 symbol("this").nud = function () { 314 scope.reserve(this); 315 this.arity = "this"; 316 return this; 317 }; 318 319 assignment("="); 320 assignment("+="); 321 assignment("-="); 322 assignment("*="); 323 assignment("/="); 324 assignment("%="); 325 assignment("&="); 326 assignment("|="); 327 assignment("^="); 328 assignment(">>="); 329 assignment(">>>="); 330 assignment("<<="); 331 332 infix("?", 20, function (left) { 333 this.first = left; 334 this.second = expression(0); 335 advance(":"); 336 this.third = expression(0); 337 this.arity = "ternary"; 338 return this; 339 }); 340 341 infixr("&", 20); 342 infixr("|", 20); 343 344 infixr("&&", 30); 345 infixr("||", 30); 346 347 infixr("in", 40); 348 infixr("==", 40); 349 infixr("!=", 40); 350 infixr("===", 40); 351 infixr("!==", 40); 352 infixr("<", 40); 353 infixr("<=", 40); 354 infixr(">", 40); 355 infixr(">=", 40); 356 infixr(">>", 40); 357 infixr(">>>", 40); 358 infixr("<<", 40); 359 360 infixr("instanceof", 45); 361 infix("+", 50); 362 infix("-", 50); 363 364 infix("^", 60); 365 infix("*", 60); 366 infix("/", 60); 367 infix("%", 60); 368 369 infix("++", 65, function (left) { 370 this.first = left; 371 this.arity = "unary"; 372 return this; 373 }); 374 infix("--", 65, function (left) { 375 this.first = left; 376 this.arity = "unary"; 377 return this; 378 }); 379 380 infix(".", 80, function (left) { 381 this.first = left; 382 //if (token.arity !== "name") { 383 // token.error("Expected a property name."); 384 //} 385 token.arity = "literal"; 386 this.second = token; 387 this.arity = "binary"; 388 advance(); 389 return this; 390 }); 391 392 infix("[", 80, function (left) { 393 this.first = left; 394 this.second = expression(0); 395 this.arity = "binary"; 396 advance("]"); 397 return this; 398 }); 399 400 infix("(", 80, function (left) { 401 var a = []; 402 if (left && (left.id === "." || left.id === "[")) { 403 this.arity = "ternary"; 404 this.first = left.first; 405 this.second = left.second; 406 this.third = a; 407 } else { 408 this.arity = "binary"; 409 this.first = left; 410 this.second = a; 411 /*if ((left.arity !== "unary" || left.id !== "function") && 412 left.arity !== "name" && left.id !== "(" && 413 left.id !== "&&" && left.id !== "||" && left.id !== "?" && 414 left.id !== "function") { 415 left.error("Expected a variable name."); 416 }*/ 417 } 418 if (token.id !== ")") { 419 while (true) { 420 a.push(expression(0)); 421 if (token.id !== ",") { 422 break; 423 } 424 advance(","); 425 } 426 } 427 advance(")"); 428 return this; 429 }); 430 431 prefix("new"); 432 433 prefix("!"); 434 prefix("~"); 435 prefix("-"); 436 prefix("+"); 437 prefix("--"); 438 prefix("++"); 439 prefix("typeof", function() { 440 var e = expression(0); 441 this.first = e; 442 return this; 443 }); 444 445 prefix("(", function () { 446 var e = expression(0); 447 advance(")"); 448 return e; 449 }); 450 451 prefix("function", function () { 452 var a = []; 453 new_scope(); 454 if (token.arity === "name") { 455 scope.define(token); 456 this.name = token.value; 457 advance(); 458 } 459 if (token.id !== "(") { 460 scope.define(token); 461 this.name = token.value; 462 advance(); 463 } 464 advance("("); 465 if (token.id !== ")") { 466 while (true) { 467 if (token.arity !== "name") { 468 token.error("Expected a parameter name."); 469 } 470 scope.define(token); 471 a.push(token); 472 advance(); 473 if (token.id !== ",") { 474 break; 475 } 476 advance(","); 477 } 478 } 479 this.first = a; 480 advance(")"); 481 this.second = block(); 482 /*advance("{"); 483 this.second = statements(); 484 advance("}");*/ 485 this.arity = "function"; 486 this.assignment = true; 487 scope.pop(); 488 return this; 489 }); 490 491 prefix("[", function () { 492 var a = []; 493 if (token.id !== "]") { 494 while (true) { 495 a.push(expression(0)); 496 if (token.id !== ",") { 497 break; 498 } 499 advance(","); 500 } 501 } 502 advance("]"); 503 this.first = a; 504 this.arity = "unary"; 505 return this; 506 }); 507 508 prefix("{", function () { 509 var a = [], n, v; 510 if (token.id !== "}") { 511 while (true) { 512 n = token; 513 if (n.arity !== "name" && n.arity !== "literal") { 514 token.error("Bad property name."); 515 } 516 advance(); 517 advance(":"); 518 v = expression(0); 519 v.key = n.value; 520 a.push(v); 521 if (token.id !== ",") { 522 break; 523 } 524 advance(","); 525 } 526 } 527 advance("}"); 528 this.first = a; 529 this.arity = "unary"; 530 return this; 531 }); 532 533 stmt("<script", function() { 534 while (token.value!==">") { 535 advance(); 536 } 537 advance(">"); 538 }); 539 540 stmt("</script", function() { 541 while (token.value!==">") { 542 advance(); 543 } 544 advance(">"); 545 }); 546 547 stmt("{", function () { 548 new_scope(); 549 var a = statements(); 550 advance("}"); 551 scope.pop(); 552 return a; 553 }); 554 555 stmt("var", function () { 556 var a = [], n, t; 557 while (true) { 558 n = token; 559 if (n.arity !== "name") { 560 n.error("Expected a new variable name."); 561 } 562 scope.define(n); 563 advance(); 564 if (token.id === "=") { 565 t = token; 566 advance("="); 567 t.first = n; 568 t.second = expression(0); 569 t.arity = "binary"; 570 a.push(t); 571 } 572 if (token.id === "in") { 573 t = token; 574 advance("in"); 575 t.first = n; 576 t.second = expression(0); 577 t.arity = "binary"; 578 a.push(t); 579 } 580 if (token.id !== ",") { 581 break; 582 } 583 advance(","); 584 } 585 if (token.id === ";") { 586 advance(";"); 587 } 588 return a.length === 0 ? null : a.length === 1 ? a[0] : a; 589 }); 590 591 stmt("try", function() { 592 this.first = block(); 593 if (token.value === "catch") { 594 this.second = statement(); 595 } 596 if (token.value === "finally") { 597 //this.third = statement(); 598 } 599 this.arity = "statement"; 600 return this; 601 }); 602 603 stmt("catch", function() { 604 advance("("); 605 if (token.id!==")") { 606 this.first = expression(0); 607 } 608 advance(")"); 609 this.second = block(); 610 this.arity = "statement"; 611 return this; 612 }); 613 614 stmt("finally", function() { 615 this.first = block(); 616 this.arity = "statement"; 617 return this; 618 }); 619 620 stmt("if", function () { 621 advance("("); 622 this.first = expression(0); 623 advance(")"); 624 if (token.value==="{") { 625 this.second = block(); 626 } else { 627 this.second = statement(); 628 } 629 if (token.id === "else") { 630 scope.reserve(token); 631 advance("else"); 632 if (token.id==="if") { 633 this.third = statement(); 634 } else if (token.value==="{") { 635 this.third = block(); 636 } else { 637 this.third = statement(); 638 } 639 //this.third = token.id === "if" ? statement() : block(); 640 } else { 641 this.third = null; 642 } 643 this.arity = "statement"; 644 return this; 645 }); 646 647 stmt("debugger", function() { 648 if (token.id === ";") { 649 advance(";"); 650 } 651 this.arity = "statement"; 652 return this; 653 }); 654 655 stmt("return", function () { 656 this.first = null; 657 this.second = null; 658 if (token.id !== ";") { 659 this.first = expression(0); 660 } 661 if (token.id === ";") { 662 advance(";"); 663 } 664 this.arity = "statement"; 665 return this; 666 }); 667 668 stmt("throw", function() { 669 this.first = expression(0); 670 if (token.id === ";") { 671 advance(";"); 672 } 673 this.arity = "statement"; 674 return this; 675 }); 676 677 stmt("delete", function() { 678 this.first = expression(0); 679 if (token.id === ";") { 680 advance(";"); 681 } 682 this.arity = "statement"; 683 return this; 684 }); 685 686 stmt("break", function () { 687 if (token.id === ";") { 688 advance(";"); 689 } 690 if (token.id !== "}" && token.id !== "case" && token.id !== "default" && token.id !== "return") { 691 //token.error("Unreachable statement."); 692 } 693 this.arity = "statement"; 694 return this; 695 }); 696 697 stmt("while", function () { 698 advance("("); 699 this.first = expression(0); 700 advance(")"); 701 if (token.value==="{") { 702 this.second = block(); 703 } else { 704 this.second = statement(); 705 } 706 this.arity = "statement"; 707 return this; 708 }); 709 710 stmt("switch", function() { 711 advance("("); 712 this.first = expression(0); 713 advance(")"); 714 this.second = block(); 715 this.arity = "statement"; 716 return this; 717 }); 718 719 stmt("case", function() { 720 this.first = expression(0); 721 advance(":"); 722 this.arity = "statement"; 723 return this; 724 }); 725 726 stmt("default", function() { 727 advance(":"); 728 this.arity = "statement"; 729 return this; 730 }); 731 732 stmt("for", function() { 733 this.first = [ ]; 734 advance("("); 735 if (token.value==="var") { 736 this.first.push(statement()); 737 } else if (token.value!==";") { 738 while (token.id!==";" && token.id!==")") { 739 this.first.push(expression(0)); 740 } 741 if (token.id===";") { 742 advance(";"); 743 } 744 } else { 745 advance(";"); 746 } 747 while (token.id!==")") { 748 if (token.value!==";") { 749 this.first.push(expression(0)); 750 if (token.id===";") { 751 advance(";"); 752 } 753 } else { 754 advance(";"); 755 } 756 } 757 advance(")"); 758 if (token.value==="{") { 759 this.second = block(); 760 } else { 761 this.second = statement(); 762 } 763 this.arity = "statement"; 764 return this; 765 }); 766 767 return function (source) { 768 tokens = source.tokens('=<>!+-*&|/%^', '=<>&|+-/'); 769 token_nr = 0; 770 new_scope(); 771 advance(); 772 var s = statements(); 773 advance("(end)"); 774 scope.pop(); 775 if (s.length) { 776 s[s.length-1].comments = nextComments; 777 } else { 778 s.comments = nextComments; 779 } 780 return s; 781 }; 782};