1 /*********************************************************************** 2 3 A JavaScript tokenizer / parser / beautifier / compressor. 4 5 This version is suitable for Node.js. With minimal changes (the 6 exports stuff) it should work on any JS platform. 7 8 This file implements some AST processors. They work on data built 9 by parse-js. 10 11 Exported functions: 12 13 - ast_mangle(ast, include_toplevel) -- mangles the 14 variable/function names in the AST. Returns an AST. Pass true 15 as second argument to mangle toplevel names too. 16 17 - ast_squeeze(ast) -- employs various optimizations to make the 18 final generated code even smaller. Returns an AST. 19 20 - gen_code(ast, beautify) -- generates JS code from the AST. Pass 21 true (or an object, see the code for some options) as second 22 argument to get "pretty" (indented) code. 23 24 -------------------------------- (C) --------------------------------- 25 26 Author: Mihai Bazon 27 <mihai.bazon (at) gmail.com> 28 http://mihai.bazon.net/blog 29 30 Distributed under the BSD license: 31 32 Copyright 2010 (c) Mihai Bazon <mihai.bazon (at) gmail.com> 33 34 Redistribution and use in source and binary forms, with or without 35 modification, are permitted provided that the following conditions 36 are met: 37 38 * Redistributions of source code must retain the above 39 copyright notice, this list of conditions and the following 40 disclaimer. 41 42 * Redistributions in binary form must reproduce the above 43 copyright notice, this list of conditions and the following 44 disclaimer in the documentation and/or other materials 45 provided with the distribution. 46 47 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AS IS AND ANY 48 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 49 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 50 PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE 51 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 52 OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 53 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 54 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 55 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR 56 TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 57 THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 58 SUCH DAMAGE. 59 60 ***********************************************************************/ 61 62 var jsp = require("./parse-js"), 63 slice = jsp.slice, 64 member = jsp.member, 65 PRECEDENCE = jsp.PRECEDENCE, 66 OPERATORS = jsp.OPERATORS; 67 68 /* -----[ helper for AST traversal ]----- */ 69 70 function ast_walker(ast) { 71 function _vardefs(defs) { 72 return [ this[0], MAP(defs, function(def){ 73 var a = [ def[0] ]; 74 if (def.length > 1) 75 a[1] = walk(def[1]); 76 return a; 77 }) ]; 78 }; 79 var walkers = { 80 "string": function(str) { 81 return [ this[0], str ]; 82 }, 83 "num": function(num) { 84 return [ this[0], num ]; 85 }, 86 "name": function(name) { 87 return [ this[0], name ]; 88 }, 89 "toplevel": function(statements) { 90 return [ this[0], MAP(statements, walk) ]; 91 }, 92 "block": function(statements) { 93 var out = [ this[0] ]; 94 if (statements != null) 95 out.push(MAP(statements, walk)); 96 return out; 97 }, 98 "var": _vardefs, 99 "const": _vardefs, 100 "try": function(t, c, f) { 101 return [ 102 this[0], 103 MAP(t, walk), 104 c != null ? [ c[0], MAP(c[1], walk) ] : null, 105 f != null ? MAP(f, walk) : null 106 ]; 107 }, 108 "throw": function(expr) { 109 return [ this[0], walk(expr) ]; 110 }, 111 "new": function(ctor, args) { 112 return [ this[0], walk(ctor), MAP(args, walk) ]; 113 }, 114 "switch": function(expr, body) { 115 return [ this[0], walk(expr), MAP(body, function(branch){ 116 return [ branch[0] ? walk(branch[0]) : null, 117 MAP(branch[1], walk) ]; 118 }) ]; 119 }, 120 "break": function(label) { 121 return [ this[0], label ]; 122 }, 123 "continue": function(label) { 124 return [ this[0], label ]; 125 }, 126 "conditional": function(cond, t, e) { 127 return [ this[0], walk(cond), walk(t), walk(e) ]; 128 }, 129 "assign": function(op, lvalue, rvalue) { 130 return [ this[0], op, walk(lvalue), walk(rvalue) ]; 131 }, 132 "dot": function(expr) { 133 return [ this[0], walk(expr) ].concat(slice(arguments, 1)); 134 }, 135 "call": function(expr, args) { 136 return [ this[0], walk(expr), MAP(args, walk) ]; 137 }, 138 "function": function(name, args, body) { 139 return [ this[0], name, args.slice(), MAP(body, walk) ]; 140 }, 141 "defun": function(name, args, body) { 142 return [ this[0], name, args.slice(), MAP(body, walk) ]; 143 }, 144 "if": function(conditional, t, e) { 145 return [ this[0], walk(conditional), walk(t), walk(e) ]; 146 }, 147 "for": function(init, cond, step, block) { 148 return [ this[0], walk(init), walk(cond), walk(step), walk(block) ]; 149 }, 150 "for-in": function(has_var, key, hash, block) { 151 return [ this[0], has_var, key, walk(hash), walk(block) ]; 152 }, 153 "while": function(cond, block) { 154 return [ this[0], walk(cond), walk(block) ]; 155 }, 156 "do": function(cond, block) { 157 return [ this[0], walk(cond), walk(block) ]; 158 }, 159 "return": function(expr) { 160 return [ this[0], walk(expr) ]; 161 }, 162 "binary": function(op, left, right) { 163 return [ this[0], op, walk(left), walk(right) ]; 164 }, 165 "unary-prefix": function(op, expr) { 166 return [ this[0], op, walk(expr) ]; 167 }, 168 "unary-postfix": function(op, expr) { 169 return [ this[0], op, walk(expr) ]; 170 }, 171 "sub": function(expr, subscript) { 172 return [ this[0], walk(expr), walk(subscript) ]; 173 }, 174 "object": function(props) { 175 return [ this[0], MAP(props, function(p){ 176 return p.length == 2 177 ? [ p[0], walk(p[1]) ] 178 : [ p[0], walk(p[1]), p[2] ]; // get/set-ter 179 }) ]; 180 }, 181 "regexp": function(rx, mods) { 182 return [ this[0], rx, mods ]; 183 }, 184 "array": function(elements) { 185 return [ this[0], MAP(elements, walk) ]; 186 }, 187 "stat": function(stat) { 188 return [ this[0], walk(stat) ]; 189 }, 190 "seq": function() { 191 return [ this[0] ].concat(MAP(slice(arguments), walk)); 192 }, 193 "label": function(name, block) { 194 return [ this[0], name, walk(block) ]; 195 }, 196 "with": function(expr, block) { 197 return [ this[0], walk(expr), walk(block) ]; 198 }, 199 "atom": function(name) { 200 return [ this[0], name ]; 201 } 202 }; 203 204 var user = {}; 205 var stack = []; 206 function walk(ast) { 207 if (ast == null) 208 return null; 209 try { 210 stack.push(ast); 211 var type = ast[0]; 212 var gen = user[type]; 213 if (gen) { 214 var ret = gen.apply(ast, ast.slice(1)); 215 if (ret != null) 216 return ret; 217 } 218 gen = walkers[type]; 219 return gen.apply(ast, ast.slice(1)); 220 } finally { 221 stack.pop(); 222 } 223 }; 224 225 function with_walkers(walkers, cont){ 226 var save = {}, i; 227 for (i in walkers) if (HOP(walkers, i)) { 228 save[i] = user[i]; 229 user[i] = walkers[i]; 230 } 231 var ret = cont(); 232 for (i in save) if (HOP(save, i)) { 233 if (!save[i]) delete user[i]; 234 else user[i] = save[i]; 235 } 236 return ret; 237 }; 238 239 return { 240 walk: walk, 241 with_walkers: with_walkers, 242 parent: function() { 243 return stack[stack.length - 2]; // last one is current node 244 }, 245 stack: function() { 246 return stack; 247 } 248 }; 249 }; 250 251 /* -----[ Scope and mangling ]----- */ 252 253 function Scope(parent) { 254 this.names = {}; // names defined in this scope 255 this.mangled = {}; // mangled names (orig.name => mangled) 256 this.rev_mangled = {}; // reverse lookup (mangled => orig.name) 257 this.cname = -1; // current mangled name 258 this.refs = {}; // names referenced from this scope 259 this.uses_with = false; // will become TRUE if eval() is detected in this or any subscopes 260 this.uses_eval = false; // will become TRUE if with() is detected in this or any subscopes 261 this.parent = parent; // parent scope 262 this.children = []; // sub-scopes 263 if (parent) { 264 this.level = parent.level + 1; 265 parent.children.push(this); 266 } else { 267 this.level = 0; 268 } 269 }; 270 271 var base54 = (function(){ 272 var DIGITS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_"; 273 return function(num) { 274 var ret = ""; 275 do { 276 ret = DIGITS.charAt(num % 54) + ret; 277 num = Math.floor(num / 54); 278 } while (num > 0); 279 return ret; 280 }; 281 })(); 282 283 Scope.prototype = { 284 has: function(name) { 285 for (var s = this; s; s = s.parent) 286 if (HOP(s.names, name)) 287 return s; 288 }, 289 has_mangled: function(mname) { 290 for (var s = this; s; s = s.parent) 291 if (HOP(s.rev_mangled, mname)) 292 return s; 293 }, 294 toJSON: function() { 295 return { 296 names: this.names, 297 uses_eval: this.uses_eval, 298 uses_with: this.uses_with 299 }; 300 }, 301 302 next_mangled: function() { 303 // we must be careful that the new mangled name: 304 // 305 // 1. doesn't shadow a mangled name from a parent 306 // scope, unless we don't reference the original 307 // name from this scope OR from any sub-scopes! 308 // This will get slow. 309 // 310 // 2. doesn't shadow an original name from a parent 311 // scope, in the event that the name is not mangled 312 // in the parent scope and we reference that name 313 // here OR IN ANY SUBSCOPES! 314 // 315 // 3. doesn't shadow a name that is referenced but not 316 // defined (possibly global defined elsewhere). 317 for (;;) { 318 var m = base54(++this.cname), prior; 319 320 // case 1. 321 prior = this.has_mangled(m); 322 if (prior && this.refs[prior.rev_mangled[m]] === prior) 323 continue; 324 325 // case 2. 326 prior = this.has(m); 327 if (prior && prior !== this && this.refs[m] === prior && !prior.has_mangled(m)) 328 continue; 329 330 // case 3. 331 if (HOP(this.refs, m) && this.refs[m] == null) 332 continue; 333 334 // I got "do" once. :-/ 335 if (!is_identifier(m)) 336 continue; 337 338 return m; 339 } 340 }, 341 get_mangled: function(name, newMangle) { 342 if (this.uses_eval || this.uses_with) return name; // no mangle if eval or with is in use 343 var s = this.has(name); 344 if (!s) return name; // not in visible scope, no mangle 345 if (HOP(s.mangled, name)) return s.mangled[name]; // already mangled in this scope 346 if (!newMangle) return name; // not found and no mangling requested 347 348 var m = s.next_mangled(); 349 s.rev_mangled[m] = name; 350 return s.mangled[name] = m; 351 }, 352 define: function(name) { 353 if (name != null) 354 return this.names[name] = name; 355 } 356 }; 357 358 function ast_add_scope(ast) { 359 360 var current_scope = null; 361 var w = ast_walker(), walk = w.walk; 362 var having_eval = []; 363 364 function with_new_scope(cont) { 365 current_scope = new Scope(current_scope); 366 var ret = current_scope.body = cont(); 367 ret.scope = current_scope; 368 current_scope = current_scope.parent; 369 return ret; 370 }; 371 372 function define(name) { 373 return current_scope.define(name); 374 }; 375 376 function reference(name) { 377 current_scope.refs[name] = true; 378 }; 379 380 function _lambda(name, args, body) { 381 return [ this[0], define(name), args, with_new_scope(function(){ 382 MAP(args, define); 383 return MAP(body, walk); 384 })]; 385 }; 386 387 return with_new_scope(function(){ 388 // process AST 389 var ret = w.with_walkers({ 390 "function": _lambda, 391 "defun": _lambda, 392 "with": function(expr, block) { 393 for (var s = current_scope; s; s = s.parent) 394 s.uses_with = true; 395 }, 396 "var": function(defs) { 397 MAP(defs, function(d){ define(d[0]) }); 398 }, 399 "const": function(defs) { 400 MAP(defs, function(d){ define(d[0]) }); 401 }, 402 "try": function(t, c, f) { 403 if (c != null) return [ 404 this[0], 405 MAP(t, walk), 406 [ define(c[0]), MAP(c[1], walk) ], 407 f != null ? MAP(f, walk) : null 408 ]; 409 }, 410 "name": function(name) { 411 if (name == "eval") 412 having_eval.push(current_scope); 413 reference(name); 414 }, 415 "for-in": function(has_var, name) { 416 if (has_var) define(name); 417 else reference(name); 418 } 419 }, function(){ 420 return walk(ast); 421 }); 422 423 // the reason why we need an additional pass here is 424 // that names can be used prior to their definition. 425 426 // scopes where eval was detected and their parents 427 // are marked with uses_eval, unless they define the 428 // "eval" name. 429 MAP(having_eval, function(scope){ 430 if (!scope.has("eval")) while (scope) { 431 scope.uses_eval = true; 432 scope = scope.parent; 433 } 434 }); 435 436 // for referenced names it might be useful to know 437 // their origin scope. current_scope here is the 438 // toplevel one. 439 function fixrefs(scope, i) { 440 // do children first; order shouldn't matter 441 for (i = scope.children.length; --i >= 0;) 442 fixrefs(scope.children[i]); 443 for (i in scope.refs) if (HOP(scope.refs, i)) { 444 // find origin scope and propagate the reference to origin 445 for (var origin = scope.has(i), s = scope; s; s = s.parent) { 446 s.refs[i] = origin; 447 if (s === origin) break; 448 } 449 } 450 }; 451 fixrefs(current_scope); 452 453 return ret; 454 }); 455 456 }; 457 458 /* -----[ mangle names ]----- */ 459 460 function ast_mangle(ast, do_toplevel) { 461 var w = ast_walker(), walk = w.walk, scope; 462 463 function get_mangled(name, newMangle) { 464 if (!do_toplevel && !scope.parent) return name; // don't mangle toplevel 465 return scope.get_mangled(name, newMangle); 466 }; 467 468 function _lambda(name, args, body) { 469 if (name) name = get_mangled(name); 470 body = with_scope(body.scope, function(){ 471 args = MAP(args, function(name){ return get_mangled(name) }); 472 return MAP(body, walk); 473 }); 474 return [ this[0], name, args, body ]; 475 }; 476 477 function with_scope(s, cont) { 478 var _scope = scope; 479 scope = s; 480 for (var i in s.names) if (HOP(s.names, i)) { 481 get_mangled(i, true); 482 } 483 var ret = cont(); 484 ret.scope = s; 485 scope = _scope; 486 return ret; 487 }; 488 489 function _vardefs(defs) { 490 return [ this[0], MAP(defs, function(d){ 491 return [ get_mangled(d[0]), walk(d[1]) ]; 492 }) ]; 493 }; 494 495 return w.with_walkers({ 496 "function": _lambda, 497 "defun": function() { 498 // move function declarations to the top when 499 // they are not in some block. 500 var ast = _lambda.apply(this, arguments); 501 switch (w.parent()[0]) { 502 case "toplevel": 503 case "function": 504 case "defun": 505 return MAP.at_top(ast); 506 } 507 return ast; 508 }, 509 "var": _vardefs, 510 "const": _vardefs, 511 "name": function(name) { 512 return [ this[0], get_mangled(name) ]; 513 }, 514 "try": function(t, c, f) { 515 return [ this[0], 516 MAP(t, walk), 517 c != null ? [ get_mangled(c[0]), MAP(c[1], walk) ] : null, 518 f != null ? MAP(f, walk) : null ]; 519 }, 520 "toplevel": function(body) { 521 var self = this; 522 return with_scope(self.scope, function(){ 523 return [ self[0], MAP(body, walk) ]; 524 }); 525 }, 526 "for-in": function(has_var, name, obj, stat) { 527 return [ this[0], has_var, get_mangled(name), walk(obj), walk(stat) ]; 528 } 529 }, function() { 530 return walk(ast_add_scope(ast)); 531 }); 532 }; 533 534 /* -----[ 535 - compress foo["bar"] into foo.bar, 536 - remove block brackets {} where possible 537 - join consecutive var declarations 538 - various optimizations for IFs: 539 - if (cond) foo(); else bar(); ==> cond?foo():bar(); 540 - if (cond) foo(); ==> cond&&foo(); 541 - if (foo) return bar(); else return baz(); ==> return foo?bar():baz(); // also for throw 542 - if (foo) return bar(); else something(); ==> {if(foo)return bar();something()} 543 ]----- */ 544 545 var warn = function(){}; 546 547 function best_of(ast1, ast2) { 548 return gen_code(ast1).length > gen_code(ast2[0] == "stat" ? ast2[1] : ast2).length ? ast2 : ast1; 549 }; 550 551 function last_stat(b) { 552 if (b[0] == "block" && b[1] && b[1].length > 0) 553 return b[1][b[1].length - 1]; 554 return b; 555 } 556 557 function aborts(t) { 558 if (t) { 559 t = last_stat(t); 560 if (t[0] == "return" || t[0] == "break" || t[0] == "continue" || t[0] == "throw") 561 return true; 562 } 563 }; 564 565 function boolean_expr(expr) { 566 return ( (expr[0] == "unary-prefix" 567 && member(expr[1], [ "!", "delete" ])) || 568 569 (expr[0] == "binary" 570 && member(expr[1], [ "in", "instanceof", "==", "!=", "===", "!==", "<", "<=", ">=", ">" ])) || 571 572 (expr[0] == "binary" 573 && member(expr[1], [ "&&", "||" ]) 574 && boolean_expr(expr[2]) 575 && boolean_expr(expr[3])) || 576 577 (expr[0] == "conditional" 578 && boolean_expr(expr[2]) 579 && boolean_expr(expr[3])) || 580 581 (expr[0] == "assign" 582 && expr[1] === true 583 && boolean_expr(expr[3])) || 584 585 (expr[0] == "seq" 586 && boolean_expr(expr[expr.length - 1])) 587 ); 588 }; 589 590 function make_conditional(c, t, e) { 591 if (c[0] == "unary-prefix" && c[1] == "!") { 592 return e ? [ "conditional", c[2], e, t ] : [ "binary", "||", c[2], t ]; 593 } else { 594 return e ? [ "conditional", c, t, e ] : [ "binary", "&&", c, t ]; 595 } 596 }; 597 598 function empty(b) { 599 return !b || (b[0] == "block" && (!b[1] || b[1].length == 0)); 600 }; 601 602 function ast_squeeze(ast, options) { 603 options = defaults(options, { 604 make_seqs : true, 605 dead_code : true, 606 keep_comps : true, 607 no_warnings : false 608 }); 609 610 var w = ast_walker(), walk = w.walk, scope; 611 612 function negate(c) { 613 var not_c = [ "unary-prefix", "!", c ]; 614 switch (c[0]) { 615 case "unary-prefix": 616 return c[1] == "!" && boolean_expr(c[2]) ? c[2] : not_c; 617 case "seq": 618 c = slice(c); 619 c[c.length - 1] = negate(c[c.length - 1]); 620 return c; 621 case "conditional": 622 return best_of(not_c, [ "conditional", c[1], negate(c[2]), negate(c[3]) ]); 623 case "binary": 624 var op = c[1], left = c[2], right = c[3]; 625 if (!options.keep_comps) switch (op) { 626 case "<=" : return [ "binary", ">", left, right ]; 627 case "<" : return [ "binary", ">=", left, right ]; 628 case ">=" : return [ "binary", "<", left, right ]; 629 case ">" : return [ "binary", "<=", left, right ]; 630 } 631 switch (op) { 632 case "==" : return [ "binary", "!=", left, right ]; 633 case "!=" : return [ "binary", "==", left, right ]; 634 case "===" : return [ "binary", "!==", left, right ]; 635 case "!==" : return [ "binary", "===", left, right ]; 636 case "&&" : return best_of(not_c, [ "binary", "||", negate(left), negate(right) ]); 637 case "||" : return best_of(not_c, [ "binary", "&&", negate(left), negate(right) ]); 638 } 639 break; 640 } 641 return not_c; 642 }; 643 644 function with_scope(s, cont) { 645 var _scope = scope; 646 scope = s; 647 var ret = cont(); 648 ret.scope = s; 649 scope = _scope; 650 return ret; 651 }; 652 653 function is_constant(node) { 654 return node[0] == "string" || node[0] == "num"; 655 }; 656 657 function rmblock(block) { 658 if (block != null && block[0] == "block" && block[1] && block[1].length == 1) 659 block = block[1][0]; 660 return block; 661 }; 662 663 function _lambda(name, args, body) { 664 return [ this[0], name, args, with_scope(body.scope, function(){ 665 return tighten(MAP(body, walk), "lambda"); 666 }) ]; 667 }; 668 669 // we get here for blocks that have been already transformed. 670 // this function does a few things: 671 // 1. discard useless blocks 672 // 2. join consecutive var declarations 673 // 3. remove obviously dead code 674 // 4. transform consecutive statements using the comma operator 675 // 5. if block_type == "lambda" and it detects constructs like if(foo) return ... - rewrite like if (!foo) { ... } 676 function tighten(statements, block_type) { 677 statements = statements.reduce(function(a, stat){ 678 if (stat[0] == "block") { 679 if (stat[1]) { 680 a.push.apply(a, stat[1]); 681 } 682 } else { 683 a.push(stat); 684 } 685 return a; 686 }, []); 687 688 statements = (function(a, prev){ 689 statements.forEach(function(cur){ 690 if (prev && ((cur[0] == "var" && prev[0] == "var") || 691 (cur[0] == "const" && prev[0] == "const"))) { 692 prev[1] = prev[1].concat(cur[1]); 693 } else { 694 a.push(cur); 695 prev = cur; 696 } 697 }); 698 return a; 699 })([]); 700 701 if (options.dead_code) statements = (function(a, has_quit){ 702 statements.forEach(function(st){ 703 if (has_quit) { 704 if (member(st[0], [ "function", "defun" , "var", "const" ])) { 705 a.push(st); 706 } 707 else if (!options.no_warnings) 708 warn("Removing unreachable code: " + gen_code(st, true)); 709 } 710 else { 711 a.push(st); 712 if (member(st[0], [ "return", "throw", "break", "continue" ])) 713 has_quit = true; 714 } 715 }); 716 return a; 717 })([]); 718 719 if (options.make_seqs) statements = (function(a, prev) { 720 statements.forEach(function(cur){ 721 if (prev && prev[0] == "stat" && cur[0] == "stat") { 722 prev[1] = [ "seq", prev[1], cur[1] ]; 723 } else { 724 a.push(cur); 725 prev = cur; 726 } 727 }); 728 return a; 729 })([]); 730 731 if (block_type == "lambda") statements = (function(i, a, stat){ 732 while (i < statements.length) { 733 stat = statements[i++]; 734 if (stat[0] == "if" && !stat[3]) { 735 if (stat[2][0] == "return" && stat[2][1] == null) { 736 a.push(make_if(negate(stat[1]), [ "block", statements.slice(i) ])); 737 break; 738 } 739 var last = last_stat(stat[2]); 740 if (last[0] == "return" && last[1] == null) { 741 a.push(make_if(stat[1], [ "block", stat[2][1].slice(0, -1) ], [ "block", statements.slice(i) ])); 742 break; 743 } 744 } 745 a.push(stat); 746 } 747 return a; 748 })(0, []); 749 750 return statements; 751 }; 752 753 function make_if(c, t, e) { 754 c = walk(c); 755 t = walk(t); 756 e = walk(e); 757 758 if (empty(t)) { 759 c = negate(c); 760 t = e; 761 e = null; 762 } else if (empty(e)) { 763 e = null; 764 } else { 765 // if we have both else and then, maybe it makes sense to switch them? 766 (function(){ 767 var a = gen_code(c); 768 var n = negate(c); 769 var b = gen_code(n); 770 if (b.length < a.length) { 771 var tmp = t; 772 t = e; 773 e = tmp; 774 c = n; 775 } 776 })(); 777 } 778 if (empty(e) && empty(t)) 779 return [ "stat", c ]; 780 var ret = [ "if", c, t, e ]; 781 if (t[0] == "if" && empty(t[3]) && empty(e)) { 782 ret = best_of(ret, walk([ "if", [ "binary", "&&", c, t[1] ], t[2] ])); 783 } 784 else if (t[0] == "stat") { 785 if (e) { 786 if (e[0] == "stat") { 787 ret = best_of(ret, [ "stat", make_conditional(c, t[1], e[1]) ]); 788 } 789 } 790 else { 791 ret = best_of(ret, [ "stat", make_conditional(c, t[1]) ]); 792 } 793 } 794 else if (e && t[0] == e[0] && (t[0] == "return" || t[0] == "throw")) { 795 ret = best_of(ret, [ t[0], make_conditional(c, t[1], e[1] ) ]); 796 } 797 else if (e && aborts(t)) { 798 ret = [ [ "if", c, t ] ]; 799 if (e[0] == "block") { 800 if (e[1]) ret = ret.concat(e[1]); 801 } 802 else { 803 ret.push(e); 804 } 805 ret = walk([ "block", ret ]); 806 } 807 else if (t && aborts(e)) { 808 ret = [ [ "if", negate(c), e ] ]; 809 if (t[0] == "block") { 810 if (t[1]) ret = ret.concat(t[1]); 811 } else { 812 ret.push(t); 813 } 814 ret = walk([ "block", ret ]); 815 } 816 return ret; 817 }; 818 819 return w.with_walkers({ 820 "sub": function(expr, subscript) { 821 if (subscript[0] == "string") { 822 var name = subscript[1]; 823 if (is_identifier(name)) { 824 return [ "dot", walk(expr), name ]; 825 } 826 } 827 }, 828 "if": make_if, 829 "toplevel": function(body) { 830 return [ "toplevel", with_scope(this.scope, function(){ 831 return tighten(MAP(body, walk)); 832 }) ]; 833 }, 834 "switch": function(expr, body) { 835 var last = body.length - 1; 836 return [ "switch", walk(expr), MAP(body, function(branch, i){ 837 var block = tighten(MAP(branch[1], walk)); 838 if (i == last && block.length > 0) { 839 var node = block[block.length - 1]; 840 if (node[0] == "break" && !node[1]) 841 block.pop(); 842 } 843 return [ branch[0] ? walk(branch[0]) : null, block ]; 844 }) ]; 845 }, 846 "function": _lambda, 847 "defun": _lambda, 848 "block": function(body) { 849 if (body) return rmblock([ "block", tighten(MAP(body, walk)) ]); 850 }, 851 "binary": function(op, left, right) { 852 left = walk(left); 853 right = walk(right); 854 var best = [ "binary", op, left, right ]; 855 if (is_constant(right) && is_constant(left)) { 856 var val = {}; 857 var orig = val; 858 switch (op) { 859 case "+" : val = left[1] + right[1]; break; 860 case "*" : val = left[1] * right[1]; break; 861 case "/" : val = left[1] / right[1]; break; 862 case "-" : val = left[1] - right[1]; break; 863 case "<<" : val = left[1] << right[1]; break; 864 case ">>" : val = left[1] >> right[1]; break; 865 case ">>>" : val = left[1] >>> right[1]; break; 866 case "==" : val = left[1] == right[1]; break; 867 case "===" : val = left[1] === right[1]; break; 868 case "!=" : val = left[1] != right[1]; break; 869 case "!==" : val = left[1] !== right[1]; break; 870 case "<" : val = left[1] < right[1]; break; 871 case "<=" : val = left[1] <= right[1]; break; 872 case ">" : val = left[1] > right[1]; break; 873 case ">=" : val = left[1] >= right[1]; break; 874 } 875 if (val !== orig) { 876 switch (typeof val) { 877 case "string": val = [ "string", val ]; break; 878 case "boolean": val = [ "name", val+"" ]; break; 879 case "number": val = [ "num", val ]; break; 880 default: return best; 881 } 882 best = best_of(best, walk(val)); 883 } 884 } 885 return best; 886 }, 887 "conditional": function(c, t, e) { 888 return make_conditional(walk(c), walk(t), walk(e)); 889 }, 890 "try": function(t, c, f) { 891 return [ 892 "try", 893 tighten(MAP(t, walk)), 894 c != null ? [ c[0], tighten(MAP(c[1], walk)) ] : null, 895 f != null ? tighten(MAP(f, walk)) : null 896 ]; 897 }, 898 "unary-prefix": function(op, expr) { 899 expr = walk(expr); 900 var ret = [ "unary-prefix", op, expr ]; 901 if (op == "!") 902 ret = best_of(ret, negate(expr)); 903 return ret; 904 }, 905 "name": function(name) { 906 switch (name) { 907 case "true": return [ "unary-prefix", "!", [ "num", 0 ]]; 908 case "false": return [ "unary-prefix", "!", [ "num", 1 ]]; 909 } 910 }, 911 "new": function(ctor, args) { 912 if (ctor[0] == "name" && ctor[1] == "Array" && !scope.has("Array")) { 913 if (args.length != 1) { 914 return [ "array", args ]; 915 } else { 916 return [ "call", [ "name", "Array" ], args ]; 917 } 918 } 919 }, 920 "call": function(expr, args) { 921 if (expr[0] == "name" && expr[1] == "Array" && args.length != 1 && !scope.has("Array")) { 922 return [ "array", args ]; 923 } 924 } 925 }, function() { 926 return walk(ast_add_scope(ast)); 927 }); 928 }; 929 930 /* -----[ re-generate code from the AST ]----- */ 931 932 var DOT_CALL_NO_PARENS = jsp.array_to_hash([ 933 "name", 934 "array", 935 "string", 936 "dot", 937 "sub", 938 "call", 939 "regexp" 940 ]); 941 942 function make_string(str) { 943 var dq = 0, sq = 0; 944 str = str.replace(/[\\\b\f\n\r\t\x22\x27]/g, function(s){ 945 switch (s) { 946 case "\\": return "\\\\"; 947 case "\b": return "\\b"; 948 case "\f": return "\\f"; 949 case "\n": return "\\n"; 950 case "\r": return "\\r"; 951 case "\t": return "\\t"; 952 case '"': ++dq; return '"'; 953 case "'": ++sq; return "'"; 954 } 955 return s; 956 }); 957 if (dq > sq) { 958 return "'" + str.replace(/\x27/g, "\\'") + "'"; 959 } else { 960 return '"' + str.replace(/\x22/g, '\\"') + '"'; 961 } 962 }; 963 964 function gen_code(ast, beautify) { 965 if (beautify) beautify = defaults(beautify, { 966 indent_start : 0, 967 indent_level : 4, 968 quote_keys : false, 969 space_colon : false 970 }); 971 var indentation = 0, 972 newline = beautify ? "\n" : "", 973 space = beautify ? " " : ""; 974 975 function indent(line) { 976 if (line == null) 977 line = ""; 978 if (beautify) 979 line = repeat_string(" ", beautify.indent_start + indentation * beautify.indent_level) + line; 980 return line; 981 }; 982 983 function with_indent(cont, incr) { 984 if (incr == null) incr = 1; 985 indentation += incr; 986 try { return cont.apply(null, slice(arguments, 1)); } 987 finally { indentation -= incr; } 988 }; 989 990 function add_spaces(a) { 991 if (beautify) 992 return a.join(" "); 993 var b = []; 994 for (var i = 0; i < a.length; ++i) { 995 var next = a[i + 1]; 996 b.push(a[i]); 997 if (next && 998 ((/[a-z0-9_\x24]$/i.test(a[i].toString()) && /^[a-z0-9_\x24]/i.test(next.toString())) || 999 (/[\+\-]$/.test(a[i].toString()) && /^[\+\-]/.test(next.toString())))) { 1000 b.push(" "); 1001 } 1002 } 1003 return b.join(""); 1004 }; 1005 1006 function add_commas(a) { 1007 return a.join("," + space); 1008 }; 1009 1010 function parenthesize(expr) { 1011 var gen = make(expr); 1012 for (var i = 1; i < arguments.length; ++i) { 1013 var el = arguments[i]; 1014 if ((el instanceof Function && el(expr)) || expr[0] == el) 1015 return "(" + gen + ")"; 1016 } 1017 return gen; 1018 }; 1019 1020 function best_of(a) { 1021 if (a.length == 1) { 1022 return a[0]; 1023 } 1024 if (a.length == 2) { 1025 var b = a[1]; 1026 a = a[0]; 1027 return a.length <= b.length ? a : b; 1028 } 1029 return best_of([ a[0], best_of(a.slice(1)) ]); 1030 }; 1031 1032 function needs_parens(expr) { 1033 if (expr[0] == "function") { 1034 // dot/call on a literal function requires the 1035 // function literal itself to be parenthesized 1036 // only if it's the first "thing" in a 1037 // statement. This means that the parent is 1038 // "stat", but it could also be a "seq" and 1039 // we're the first in this "seq" and the 1040 // parent is "stat", and so on. Messy stuff, 1041 // but it worths the trouble. 1042 var a = slice($stack), self = a.pop(), p = a.pop(); 1043 while (p) { 1044 if (p[0] == "stat") return true; 1045 if ((p[0] == "seq" && p[1] === self) || 1046 (p[0] == "call" && p[1] === self) || 1047 (p[0] == "binary" && p[2] === self)) { 1048 self = p; 1049 p = a.pop(); 1050 } else { 1051 return false; 1052 } 1053 } 1054 } 1055 return !HOP(DOT_CALL_NO_PARENS, expr[0]); 1056 }; 1057 1058 function make_num(num) { 1059 var str = num.toString(10), a = [ str.replace(/^0\./, ".") ], m; 1060 if (Math.floor(num) === num) { 1061 a.push("0x" + num.toString(16).toLowerCase(), // probably pointless 1062 "0" + num.toString(8)); // same. 1063 if ((m = /^(.*?)(0+)$/.exec(num))) { 1064 a.push(m[1] + "e" + m[2].length); 1065 } 1066 } else if ((m = /^0?\.(0+)(.*)$/.exec(num))) { 1067 a.push(m[2] + "e-" + (m[1].length + m[2].length), 1068 str.substr(str.indexOf("."))); 1069 } 1070 return best_of(a); 1071 }; 1072 1073 var generators = { 1074 "string": make_string, 1075 "num": make_num, 1076 "name": make_name, 1077 "toplevel": function(statements) { 1078 return make_block_statements(statements) 1079 .join(newline + newline); 1080 }, 1081 "block": make_block, 1082 "var": function(defs) { 1083 return "var " + add_commas(MAP(defs, make_1vardef)) + ";"; 1084 }, 1085 "const": function(defs) { 1086 return "const " + add_commas(MAP(defs, make_1vardef)) + ";"; 1087 }, 1088 "try": function(tr, ca, fi) { 1089 var out = [ "try", make_block(tr) ]; 1090 if (ca) out.push("catch", "(" + ca[0] + ")", make_block(ca[1])); 1091 if (fi) out.push("finally", make_block(fi)); 1092 return add_spaces(out); 1093 }, 1094 "throw": function(expr) { 1095 return add_spaces([ "throw", make(expr) ]) + ";"; 1096 }, 1097 "new": function(ctor, args) { 1098 args = args.length > 0 ? "(" + add_commas(MAP(args, make)) + ")" : ""; 1099 return add_spaces([ "new", parenthesize(ctor, "seq", "binary", "conditional", "assign", function(expr){ 1100 var w = ast_walker(), has_call = {}; 1101 try { 1102 w.with_walkers({ 1103 "call": function() { throw has_call }, 1104 "function": function() { return this } 1105 }, function(){ 1106 w.walk(expr); 1107 }); 1108 } catch(ex) { 1109 if (ex === has_call) 1110 return true; 1111 throw ex; 1112 } 1113 }) + args ]); 1114 }, 1115 "switch": function(expr, body) { 1116 return add_spaces([ "switch", "(" + make(expr) + ")", make_switch_block(body) ]); 1117 }, 1118 "break": function(label) { 1119 var out = "break"; 1120 if (label != null) 1121 out += " " + make_name(label); 1122 return out + ";"; 1123 }, 1124 "continue": function(label) { 1125 var out = "continue"; 1126 if (label != null) 1127 out += " " + make_name(label); 1128 return out + ";"; 1129 }, 1130 "conditional": function(co, th, el) { 1131 return add_spaces([ parenthesize(co, "assign", "seq", "conditional"), "?", 1132 parenthesize(th, "seq"), ":", 1133 parenthesize(el, "seq") ]); 1134 }, 1135 "assign": function(op, lvalue, rvalue) { 1136 if (op && op !== true) op += "="; 1137 else op = "="; 1138 return add_spaces([ make(lvalue), op, parenthesize(rvalue, "seq") ]); 1139 }, 1140 "dot": function(expr) { 1141 var out = make(expr), i = 1; 1142 if (expr[0] == "num") 1143 out += "."; 1144 else if (needs_parens(expr)) 1145 out = "(" + out + ")"; 1146 while (i < arguments.length) 1147 out += "." + make_name(arguments[i++]); 1148 return out; 1149 }, 1150 "call": function(func, args) { 1151 var f = make(func); 1152 if (needs_parens(func)) 1153 f = "(" + f + ")"; 1154 return f + "(" + add_commas(MAP(args, function(expr){ 1155 return parenthesize(expr, "seq"); 1156 })) + ")"; 1157 }, 1158 "function": make_function, 1159 "defun": make_function, 1160 "if": function(co, th, el) { 1161 var out = [ "if", "(" + make(co) + ")", el ? make_then(th) : make(th) ]; 1162 if (el) { 1163 out.push("else", make(el)); 1164 } 1165 return add_spaces(out); 1166 }, 1167 "for": function(init, cond, step, block) { 1168 var out = [ "for" ]; 1169 init = (init != null ? make(init) : "").replace(/;*\s*$/, ";" + space); 1170 cond = (cond != null ? make(cond) : "").replace(/;*\s*$/, ";" + space); 1171 step = (step != null ? make(step) : "").replace(/;*\s*$/, ""); 1172 var args = init + cond + step; 1173 if (args == "; ; ") args = ";;"; 1174 out.push("(" + args + ")", make(block)); 1175 return add_spaces(out); 1176 }, 1177 "for-in": function(has_var, key, hash, block) { 1178 var out = add_spaces([ "for", "(" ]); 1179 if (has_var) 1180 out += "var "; 1181 out += add_spaces([ make_name(key) + " in " + make(hash) + ")", make(block) ]); 1182 return out; 1183 }, 1184 "while": function(condition, block) { 1185 return add_spaces([ "while", "(" + make(condition) + ")", make(block) ]); 1186 }, 1187 "do": function(condition, block) { 1188 return add_spaces([ "do", make(block), "while", "(" + make(condition) + ")" ]) + ";"; 1189 }, 1190 "return": function(expr) { 1191 var out = [ "return" ]; 1192 if (expr != null) out.push(make(expr)); 1193 return add_spaces(out) + ";"; 1194 }, 1195 "binary": function(operator, lvalue, rvalue) { 1196 var left = make(lvalue), right = make(rvalue); 1197 // XXX: I'm pretty sure other cases will bite here. 1198 // we need to be smarter. 1199 // adding parens all the time is the safest bet. 1200 if (member(lvalue[0], [ "assign", "conditional", "seq" ]) || 1201 lvalue[0] == "binary" && PRECEDENCE[operator] > PRECEDENCE[lvalue[1]]) { 1202 left = "(" + left + ")"; 1203 } 1204 if (member(rvalue[0], [ "assign", "conditional", "seq" ]) || 1205 rvalue[0] == "binary" && PRECEDENCE[operator] >= PRECEDENCE[rvalue[1]] && 1206 !(rvalue[1] == operator && member(operator, [ "&&", "||", "*" ]))) { 1207 right = "(" + right + ")"; 1208 } 1209 return add_spaces([ left, operator, right ]); 1210 }, 1211 "unary-prefix": function(operator, expr) { 1212 var val = make(expr); 1213 if (!(expr[0] == "num" || (expr[0] == "unary-prefix" && !HOP(OPERATORS, operator + expr[1])) || !needs_parens(expr))) 1214 val = "(" + val + ")"; 1215 return operator + (jsp.is_alphanumeric_char(operator.charAt(0)) ? " " : "") + val; 1216 }, 1217 "unary-postfix": function(operator, expr) { 1218 var val = make(expr); 1219 if (!(expr[0] == "num" || (expr[0] == "unary-postfix" && !HOP(OPERATORS, operator + expr[1])) || !needs_parens(expr))) 1220 val = "(" + val + ")"; 1221 return val + operator; 1222 }, 1223 "sub": function(expr, subscript) { 1224 var hash = make(expr); 1225 if (needs_parens(expr)) 1226 hash = "(" + hash + ")"; 1227 return hash + "[" + make(subscript) + "]"; 1228 }, 1229 "object": function(props) { 1230 if (props.length == 0) 1231 return "{}"; 1232 return "{" + newline + with_indent(function(){ 1233 return MAP(props, function(p){ 1234 if (p.length == 3) { 1235 // getter/setter. The name is in p[0], the arg.list in p[1][2], the 1236 // body in p[1][3] and type ("get" / "set") in p[2]. 1237 return indent(make_function(p[0], p[1][2], p[1][3], p[2])); 1238 } 1239 var key = p[0], val = make(p[1]); 1240 if (beautify && beautify.quote_keys) { 1241 key = make_string(key); 1242 } else if ((typeof key == "number" || !beautify && +key + "" == key) 1243 && parseFloat(key) >= 0) { 1244 key = make_num(+key); 1245 } else if (!is_identifier(key)) { 1246 key = make_string(key); 1247 } 1248 return indent(add_spaces(beautify && beautify.space_colon 1249 ? [ key, ":", val ] 1250 : [ key + ":", val ])); 1251 }).join("," + newline); 1252 }) + newline + indent("}"); 1253 }, 1254 "regexp": function(rx, mods) { 1255 return "/" + rx + "/" + mods; 1256 }, 1257 "array": function(elements) { 1258 if (elements.length == 0) return "[]"; 1259 return add_spaces([ "[", add_commas(MAP(elements, function(el){ 1260 if (!beautify && el[0] == "atom" && el[1] == "undefined") return ""; 1261 return parenthesize(el, "seq"); 1262 })), "]" ]); 1263 }, 1264 "stat": function(stmt) { 1265 return make(stmt).replace(/;*\s*$/, ";"); 1266 }, 1267 "seq": function() { 1268 return add_commas(MAP(slice(arguments), make)); 1269 }, 1270 "label": function(name, block) { 1271 return add_spaces([ make_name(name), ":", make(block) ]); 1272 }, 1273 "with": function(expr, block) { 1274 return add_spaces([ "with", "(" + make(expr) + ")", make(block) ]); 1275 }, 1276 "atom": function(name) { 1277 return make_name(name); 1278 } 1279 }; 1280 1281 // The squeezer replaces "block"-s that contain only a single 1282 // statement with the statement itself; technically, the AST 1283 // is correct, but this can create problems when we output an 1284 // IF having an ELSE clause where the THEN clause ends in an 1285 // IF *without* an ELSE block (then the outer ELSE would refer 1286 // to the inner IF). This function checks for this case and 1287 // adds the block brackets if needed. 1288 function make_then(th) { 1289 if (th[0] == "do") { 1290 // https://github.com/mishoo/UglifyJS/issues/#issue/57 1291 // IE croaks with "syntax error" on code like this: 1292 // if (foo) do ... while(cond); else ... 1293 // we need block brackets around do/while 1294 return make([ "block", [ th ]]); 1295 } 1296 var b = th; 1297 while (true) { 1298 var type = b[0]; 1299 if (type == "if") { 1300 if (!b[3]) 1301 // no else, we must add the block 1302 return make([ "block", [ th ]]); 1303 b = b[3]; 1304 } 1305 else if (type == "while" || type == "do") b = b[2]; 1306 else if (type == "for" || type == "for-in") b = b[4]; 1307 else break; 1308 } 1309 return make(th); 1310 }; 1311 1312 function make_function(name, args, body, keyword) { 1313 var out = keyword || "function"; 1314 if (name) { 1315 out += " " + make_name(name); 1316 } 1317 out += "(" + add_commas(MAP(args, make_name)) + ")"; 1318 return add_spaces([ out, make_block(body) ]); 1319 }; 1320 1321 function make_name(name) { 1322 return name.toString(); 1323 }; 1324 1325 function make_block_statements(statements) { 1326 for (var a = [], last = statements.length - 1, i = 0; i <= last; ++i) { 1327 var stat = statements[i]; 1328 var code = make(stat); 1329 if (code != ";") { 1330 if (!beautify && i == last) { 1331 if ((stat[0] == "while" && empty(stat[2])) || 1332 (member(stat[0], [ "for", "for-in"] ) && empty(stat[4])) || 1333 (stat[0] == "if" && empty(stat[2]) && !stat[3]) || 1334 (stat[0] == "if" && stat[3] && empty(stat[3]))) { 1335 code = code.replace(/;*\s*$/, ";"); 1336 } else { 1337 code = code.replace(/;+\s*$/, ""); 1338 } 1339 } 1340 a.push(code); 1341 } 1342 } 1343 return MAP(a, indent); 1344 }; 1345 1346 function make_switch_block(body) { 1347 var n = body.length; 1348 if (n == 0) return "{}"; 1349 return "{" + newline + MAP(body, function(branch, i){ 1350 var has_body = branch[1].length > 0, code = with_indent(function(){ 1351 return indent(branch[0] 1352 ? add_spaces([ "case", make(branch[0]) + ":" ]) 1353 : "default:"); 1354 }, 0.5) + (has_body ? newline + with_indent(function(){ 1355 return make_block_statements(branch[1]).join(newline); 1356 }) : ""); 1357 if (!beautify && has_body && i < n - 1) 1358 code += ";"; 1359 return code; 1360 }).join(newline) + newline + indent("}"); 1361 }; 1362 1363 function make_block(statements) { 1364 if (!statements) return ";"; 1365 if (statements.length == 0) return "{}"; 1366 return "{" + newline + with_indent(function(){ 1367 return make_block_statements(statements).join(newline); 1368 }) + newline + indent("}"); 1369 }; 1370 1371 function make_1vardef(def) { 1372 var name = def[0], val = def[1]; 1373 if (val != null) 1374 name = add_spaces([ name, "=", make(val) ]); 1375 return name; 1376 }; 1377 1378 var $stack = []; 1379 1380 function make(node) { 1381 var type = node[0]; 1382 var gen = generators[type]; 1383 if (!gen) 1384 throw new Error("Can't find generator for \"" + type + "\""); 1385 $stack.push(node); 1386 var ret = gen.apply(type, node.slice(1)); 1387 $stack.pop(); 1388 return ret; 1389 }; 1390 1391 return make(ast); 1392 }; 1393 1394 function split_lines(code, max_line_length) { 1395 var splits = [ 0 ]; 1396 jsp.parse(function(){ 1397 var next_token = jsp.tokenizer(code); 1398 var last_split = 0; 1399 var prev_token; 1400 function current_length(tok) { 1401 return tok.pos - last_split; 1402 }; 1403 function split_here(tok) { 1404 last_split = tok.pos; 1405 splits.push(last_split); 1406 }; 1407 function custom(){ 1408 var tok = next_token.apply(this, arguments); 1409 out: { 1410 if (prev_token) { 1411 if (prev_token.type == "keyword") break out; 1412 } 1413 if (current_length(tok) > max_line_length) { 1414 switch (tok.type) { 1415 case "keyword": 1416 case "atom": 1417 case "name": 1418 case "punc": 1419 split_here(tok); 1420 break out; 1421 } 1422 } 1423 } 1424 prev_token = tok; 1425 return tok; 1426 }; 1427 custom.context = function() { 1428 return next_token.context.apply(this, arguments); 1429 }; 1430 return custom; 1431 }()); 1432 return splits.map(function(pos, i){ 1433 return code.substring(pos, splits[i + 1] || code.length); 1434 }).join("\n"); 1435 }; 1436 1437 /* -----[ Utilities ]----- */ 1438 1439 function repeat_string(str, i) { 1440 if (i <= 0) return ""; 1441 if (i == 1) return str; 1442 var d = repeat_string(str, i >> 1); 1443 d += d; 1444 if (i & 1) d += str; 1445 return d; 1446 }; 1447 1448 function defaults(args, defs) { 1449 var ret = {}; 1450 if (args === true) 1451 args = {}; 1452 for (var i in defs) if (HOP(defs, i)) { 1453 ret[i] = (args && HOP(args, i)) ? args[i] : defs[i]; 1454 } 1455 return ret; 1456 }; 1457 1458 function is_identifier(name) { 1459 return /^[a-z_$][a-z0-9_$]*$/i.test(name) 1460 && name != "this" 1461 && !HOP(jsp.KEYWORDS_ATOM, name) 1462 && !HOP(jsp.RESERVED_WORDS, name) 1463 && !HOP(jsp.KEYWORDS, name); 1464 }; 1465 1466 function HOP(obj, prop) { 1467 return Object.prototype.hasOwnProperty.call(obj, prop); 1468 }; 1469 1470 // some utilities 1471 1472 var MAP; 1473 1474 (function(){ 1475 MAP = function(a, f, o) { 1476 var ret = []; 1477 for (var i = 0; i < a.length; ++i) { 1478 var val = f.call(o, a[i], i); 1479 if (val instanceof AtTop) ret.unshift(val.v); 1480 else ret.push(val); 1481 } 1482 return ret; 1483 }; 1484 MAP.at_top = function(val) { return new AtTop(val) }; 1485 function AtTop(val) { this.v = val }; 1486 })(); 1487 1488 /* -----[ Exports ]----- */ 1489 1490 exports.ast_walker = ast_walker; 1491 exports.ast_mangle = ast_mangle; 1492 exports.ast_squeeze = ast_squeeze; 1493 exports.gen_code = gen_code; 1494 exports.ast_add_scope = ast_add_scope; 1495 exports.ast_squeeze_more = require("./squeeze-more").ast_squeeze_more; 1496 exports.set_logger = function(logger) { warn = logger }; 1497 exports.make_string = make_string; 1498 exports.split_lines = split_lines; 1499
