Replace.cpp

   1 /* Cycript - Optimizing JavaScript Compiler/Runtime
   2  * Copyright (C) 2009-2015  Jay Freeman (saurik)
   3 */
   4
   5 /* GNU Affero General Public License, Version 3 {{{ */
   6 /*
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as published by
   9  * the Free Software Foundation, either version 3 of the License, or
  10  * (at your option) any later version.
  11
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 **/
  20 /* }}} */
  21
  22 #include <iomanip>
  23
  24 #include "Replace.hpp"
  25 #include "Syntax.hpp"
  26
  27 CYFunctionExpression *CYNonLocalize(CYContext &context, CYFunctionExpression *function) {
  28     function->nonlocal_ = context.nextlocal_;
  29     return function;
  30 }
  31
  32 static void CYImplicitReturn(CYStatement *&code) {
  33     if (CYStatement *&last = CYGetLast(code))
  34         last = last->Return();
  35 }
  36
  37 CYExpression *CYAdd::Replace(CYContext &context) {
  38     CYInfix::Replace(context);
  39
  40     CYString *lhs(dynamic_cast<CYString *>(lhs_));
  41     CYString *rhs(dynamic_cast<CYString *>(rhs_));
  42
  43     if (lhs != NULL || rhs != NULL) {
  44         if (lhs == NULL) {
  45             lhs = lhs_->String(context);
  46             if (lhs == NULL)
  47                 return this;
  48         } else if (rhs == NULL) {
  49             rhs = rhs_->String(context);
  50             if (rhs == NULL)
  51                 return this;
  52         }
  53
  54         return lhs->Concat(context, rhs);
  55     }
  56
  57     if (CYNumber *lhn = lhs_->Number(context))
  58         if (CYNumber *rhn = rhs_->Number(context))
  59             return $D(lhn->Value() + rhn->Value());
  60
  61     return this;
  62 }
  63
  64 CYExpression *CYAddressOf::Replace(CYContext &context) {
  65     return $C0($M(rhs_, $S("$cya")));
  66 }
  67
  68 CYArgument *CYArgument::Replace(CYContext &context) { $T(NULL)
  69     context.Replace(value_);
  70     next_ = next_->Replace(context);
  71
  72     if (value_ == NULL) {
  73         if (next_ == NULL)
  74             return NULL;
  75         else
  76             value_ = $U;
  77     }
  78
  79     return this;
  80 }
  81
  82 CYExpression *CYArray::Replace(CYContext &context) {
  83     if (elements_ != NULL)
  84         elements_->Replace(context);
  85     return this;
  86 }
  87
  88 CYExpression *CYArrayComprehension::Replace(CYContext &context) {
  89     CYVariable *cyv($V("$cyv"));
  90
  91     return $C0($F(NULL, $P1($L("$cyv"), comprehensions_->Parameters(context)), $$->*
  92         $E($ CYAssign(cyv, $ CYArray()))->*
  93         comprehensions_->Replace(context, $E($C1($M(cyv, $S("push")), expression_)))->*
  94         $ CYReturn(cyv)
  95     ));
  96 }
  97
  98 CYExpression *CYAssignment::Replace(CYContext &context) {
  99     context.Replace(lhs_);
 100     context.Replace(rhs_);
 101     return this;
 102 }
 103
 104 CYStatement *CYBlock::Return() {
 105     CYImplicitReturn(code_);
 106     return this;
 107 }
 108
 109 CYStatement *CYBlock::Replace(CYContext &context) {
 110     context.ReplaceAll(code_);
 111     if (code_ == NULL)
 112         return $ CYEmpty();
 113     return this;
 114 }
 115
 116 CYStatement *CYBreak::Replace(CYContext &context) {
 117     return this;
 118 }
 119
 120 CYExpression *CYCall::AddArgument(CYContext &context, CYExpression *value) {
 121     CYArgument **argument(&arguments_);
 122     while (*argument != NULL)
 123         argument = &(*argument)->next_;
 124     *argument = $ CYArgument(value);
 125     return this;
 126 }
 127
 128 CYExpression *CYCall::Replace(CYContext &context) {
 129     context.Replace(function_);
 130     arguments_->Replace(context);
 131     return this;
 132 }
 133
 134 namespace cy {
 135 namespace Syntax {
 136
 137 void Catch::Replace(CYContext &context) { $T()
 138     CYScope scope(true, context);
 139
 140     context.Replace(name_);
 141     context.scope_->Declare(context, name_, CYIdentifierCatch);
 142
 143     context.ReplaceAll(code_);
 144     scope.Close(context, code_);
 145 }
 146
 147 } }
 148
 149 void CYClause::Replace(CYContext &context) { $T()
 150     context.Replace(case_);
 151     context.ReplaceAll(code_);
 152     next_->Replace(context);
 153 }
 154
 155 CYExpression *CYCompound::Replace(CYContext &context) {
 156     context.Replace(expression_);
 157     context.Replace(next_);
 158
 159     if (CYCompound *compound = dynamic_cast<CYCompound *>(expression_)) {
 160         expression_ = compound->expression_;
 161         compound->expression_ = compound->next_;
 162         compound->next_ = next_;
 163         next_ = compound;
 164     }
 165
 166     return this;
 167 }
 168
 169 CYFunctionParameter *CYCompound::Parameter() const {
 170     CYFunctionParameter *next(next_->Parameter());
 171     if (next == NULL)
 172         return NULL;
 173
 174     CYFunctionParameter *parameter(expression_->Parameter());
 175     if (parameter == NULL)
 176         return NULL;
 177
 178     parameter->SetNext(next);
 179     return parameter;
 180 }
 181
 182 CYFunctionParameter *CYComprehension::Parameters(CYContext &context) const { $T(NULL)
 183     CYFunctionParameter *next(next_->Parameters(context));
 184     if (CYFunctionParameter *parameter = Parameter(context)) {
 185         parameter->SetNext(next);
 186         return parameter;
 187     } else
 188         return next;
 189 }
 190
 191 CYStatement *CYComprehension::Replace(CYContext &context, CYStatement *statement) const {
 192     return next_ == NULL ? statement : next_->Replace(context, statement);
 193 }
 194
 195 CYExpression *CYCondition::Replace(CYContext &context) {
 196     context.Replace(test_);
 197     context.Replace(true_);
 198     context.Replace(false_);
 199     return this;
 200 }
 201
 202 void CYContext::NonLocal(CYStatement *&statements) {
 203     CYContext &context(*this);
 204
 205     if (nextlocal_ != NULL && nextlocal_->identifier_ != NULL) {
 206         CYIdentifier *cye($I("$cye")->Replace(context));
 207         CYIdentifier *unique(nextlocal_->identifier_->Replace(context));
 208
 209         CYStatement *declare(
 210             $ CYVar($L1($ CYDeclaration(unique, $ CYObject()))));
 211
 212         cy::Syntax::Catch *rescue(
 213             $ cy::Syntax::Catch(cye, $$->*
 214                 $ CYIf($ CYIdentical($M($V(cye), $S("$cyk")), $V(unique)), $$->*
 215                     $ CYReturn($M($V(cye), $S("$cyv"))))->*
 216                 $ cy::Syntax::Throw($V(cye))));
 217
 218         // XXX: I don't understand any of this
 219         context.Replace(declare);
 220         rescue->Replace(context);
 221
 222         statements = $$->*
 223             declare->*
 224             $ cy::Syntax::Try(statements, rescue, NULL);
 225     }
 226 }
 227
 228 CYIdentifier *CYContext::Unique() {
 229     return $ CYIdentifier($pool.strcat("$cy", $pool.itoa(unique_++), NULL));
 230 }
 231
 232 CYStatement *CYContinue::Replace(CYContext &context) {
 233     return this;
 234 }
 235
 236 CYStatement *CYDebugger::Replace(CYContext &context) {
 237     return this;
 238 }
 239
 240 CYAssignment *CYDeclaration::Assignment(CYContext &context) {
 241     if (initialiser_ == NULL)
 242         return NULL;
 243
 244     CYAssignment *value($ CYAssign(Variable(context), initialiser_));
 245     initialiser_ = NULL;
 246     return value;
 247 }
 248
 249 CYVariable *CYDeclaration::Variable(CYContext &context) {
 250     return $V(identifier_);
 251 }
 252
 253 CYStatement *CYDeclaration::ForEachIn(CYContext &context, CYExpression *value) {
 254     return $ CYVar($L1($ CYDeclaration(identifier_, value)));
 255 }
 256
 257 CYExpression *CYDeclaration::Replace(CYContext &context) {
 258     context.Replace(identifier_);
 259     context.scope_->Declare(context, identifier_, CYIdentifierVariable);
 260     return Variable(context);
 261 }
 262
 263 void CYDeclarations::Replace(CYContext &context) { $T()
 264     declaration_->Replace(context);
 265     next_->Replace(context);
 266 }
 267
 268 CYProperty *CYDeclarations::Property(CYContext &context) { $T(NULL)
 269     return $ CYProperty(declaration_->identifier_, declaration_->initialiser_, next_->Property(context));
 270 }
 271
 272 CYFunctionParameter *CYDeclarations::Parameter(CYContext &context) { $T(NULL)
 273     return $ CYFunctionParameter($ CYDeclaration(declaration_->identifier_), next_->Parameter(context));
 274 }
 275
 276 CYArgument *CYDeclarations::Argument(CYContext &context) { $T(NULL)
 277     return $ CYArgument(declaration_->initialiser_, next_->Argument(context));
 278 }
 279
 280 CYExpression *CYDeclarations::Expression(CYContext &context) { $T(NULL)
 281     CYExpression *compound(next_->Expression(context));
 282     if (CYAssignment *assignment = declaration_->Assignment(context))
 283         if (compound == NULL)
 284             compound = assignment;
 285         else
 286             compound = $ CYCompound(assignment, compound);
 287     return compound;
 288 }
 289
 290 CYExpression *CYDirectMember::Replace(CYContext &context) {
 291     context.Replace(object_);
 292     context.Replace(property_);
 293     return this;
 294 }
 295
 296 CYStatement *CYDoWhile::Replace(CYContext &context) {
 297     context.Replace(test_);
 298     context.ReplaceAll(code_);
 299     return this;
 300 }
 301
 302 void CYElementSpread::Replace(CYContext &context) {
 303     context.Replace(value_);
 304 }
 305
 306 void CYElementValue::Replace(CYContext &context) {
 307     context.Replace(value_);
 308     if (next_ != NULL)
 309         next_->Replace(context);
 310 }
 311
 312 CYStatement *CYEmpty::Replace(CYContext &context) {
 313     return NULL;
 314 }
 315
 316 CYExpression *CYEncodedType::Replace(CYContext &context) {
 317     return typed_->Replace(context);
 318 }
 319
 320 CYStatement *CYExpress::Return() {
 321     return $ CYReturn(expression_);
 322 }
 323
 324 CYStatement *CYExpress::Replace(CYContext &context) {
 325     context.Replace(expression_);
 326     return this;
 327 }
 328
 329 CYExpression *CYExpression::AddArgument(CYContext &context, CYExpression *value) {
 330     return $C1(this, value);
 331 }
 332
 333 CYExpression *CYExpression::ClassName(CYContext &context, bool object) {
 334     return this;
 335 }
 336
 337 CYStatement *CYExpression::ForEachIn(CYContext &context, CYExpression *value) {
 338     return $E($ CYAssign(this, value));
 339 }
 340
 341 CYAssignment *CYExpression::Assignment(CYContext &context) {
 342     return NULL;
 343 }
 344
 345 CYFunctionParameter *CYExpression::Parameter() const {
 346     return NULL;
 347 }
 348
 349 CYStatement *CYExternal::Replace(CYContext &context) {
 350     return $E($ CYAssign($V(typed_->identifier_), $C1(typed_->Replace(context), $C2($V("dlsym"), $V("RTLD_DEFAULT"), $S(typed_->identifier_->Word())))));
 351 }
 352
 353 CYNumber *CYFalse::Number(CYContext &context) {
 354     return $D(0);
 355 }
 356
 357 CYString *CYFalse::String(CYContext &context) {
 358     return $S("false");
 359 }
 360
 361 CYExpression *CYFatArrow::Replace(CYContext &context) {
 362     CYFunctionExpression *function($ CYFunctionExpression(NULL, parameters_, code_));
 363     function->this_.SetNext(context.this_);
 364     return function;
 365 }
 366
 367 void CYFinally::Replace(CYContext &context) { $T()
 368     context.ReplaceAll(code_);
 369 }
 370
 371 CYStatement *CYFor::Replace(CYContext &context) {
 372     context.Replace(initialiser_);
 373     context.Replace(test_);
 374     context.Replace(increment_);
 375     context.ReplaceAll(code_);
 376     return this;
 377 }
 378
 379 CYExpression *CYForDeclarations::Replace(CYContext &context) {
 380     declarations_->Replace(context);
 381     return declarations_->Expression(context);
 382 }
 383
 384 // XXX: this still feels highly suboptimal
 385 CYStatement *CYForIn::Replace(CYContext &context) {
 386     if (CYAssignment *assignment = initialiser_->Assignment(context))
 387         return $ CYBlock($$->*
 388             $E(assignment)->*
 389             this
 390         );
 391
 392     context.Replace(initialiser_);
 393     context.Replace(set_);
 394     context.ReplaceAll(code_);
 395     return this;
 396 }
 397
 398 CYFunctionParameter *CYForInComprehension::Parameter(CYContext &context) const {
 399     return $ CYFunctionParameter(declaration_);
 400 }
 401
 402 CYStatement *CYForInComprehension::Replace(CYContext &context, CYStatement *statement) const {
 403     return $ CYForIn(declaration_->Variable(context), set_, CYComprehension::Replace(context, statement));
 404 }
 405
 406 CYStatement *CYForOf::Replace(CYContext &context) {
 407     if (CYAssignment *assignment = initialiser_->Assignment(context))
 408         return $ CYBlock($$->*
 409             $E(assignment)->*
 410             this
 411         );
 412
 413     CYIdentifier *cys($I("$cys")), *cyt($I("$cyt"));
 414
 415     return $ CYLetStatement($L2($ CYDeclaration(cys, set_), $ CYDeclaration(cyt)), $$->*
 416         $ CYForIn($V(cyt), $V(cys), $ CYBlock($$->*
 417             initialiser_->ForEachIn(context, $M($V(cys), $V(cyt)))->*
 418             code_
 419         ))
 420     );
 421 }
 422
 423 CYFunctionParameter *CYForOfComprehension::Parameter(CYContext &context) const {
 424     return $ CYFunctionParameter(declaration_);
 425 }
 426
 427 CYStatement *CYForOfComprehension::Replace(CYContext &context, CYStatement *statement) const {
 428     CYIdentifier *cys($I("$cys"));
 429
 430     return $E($C0($F(NULL, $P1($L("$cys")), $$->*
 431         $E($ CYAssign($V(cys), set_))->*
 432         $ CYForIn(declaration_->Variable(context), $V(cys), $ CYBlock($$->*
 433             $E($ CYAssign(declaration_->Variable(context), $M($V(cys), declaration_->Variable(context))))->*
 434             CYComprehension::Replace(context, statement)
 435         ))
 436     )));
 437 }
 438
 439 void CYFunction::Inject(CYContext &context) {
 440     context.Replace(name_);
 441     context.scope_->Declare(context, name_, CYIdentifierOther);
 442 }
 443
 444 void CYFunction::Replace_(CYContext &context, bool outer) {
 445     if (outer)
 446         Inject(context);
 447
 448     CYThisScope *_this(context.this_);
 449     context.this_ = &this_;
 450     context.this_ = CYGetLast(context.this_);
 451
 452     CYNonLocal *nonlocal(context.nonlocal_);
 453     CYNonLocal *nextlocal(context.nextlocal_);
 454
 455     bool localize;
 456     if (nonlocal_ != NULL) {
 457         localize = false;
 458         context.nonlocal_ = nonlocal_;
 459     } else {
 460         localize = true;
 461         nonlocal_ = $ CYNonLocal();
 462         context.nextlocal_ = nonlocal_;
 463     }
 464
 465     CYScope scope(!localize, context);
 466
 467     if (!outer && name_ != NULL)
 468         Inject(context);
 469
 470     parameters_->Replace(context, code_);
 471     context.ReplaceAll(code_);
 472
 473     if (implicit_)
 474         CYImplicitReturn(code_);
 475
 476     if (CYIdentifier *identifier = this_.identifier_)
 477         code_ = $$->*
 478             $ CYVar($L1($ CYDeclaration(identifier, $ CYThis())))->*
 479             code_;
 480
 481     if (localize)
 482         context.NonLocal(code_);
 483
 484     context.nextlocal_ = nextlocal;
 485     context.nonlocal_ = nonlocal;
 486
 487     context.this_ = _this;
 488
 489     scope.Close(context, code_);
 490 }
 491
 492 CYExpression *CYFunctionExpression::Replace(CYContext &context) {
 493     Replace_(context, false);
 494     return this;
 495 }
 496
 497 void CYFunctionParameter::Replace(CYContext &context, CYStatement *&statements) { $T()
 498     CYAssignment *assignment(initialiser_->Assignment(context));
 499     context.Replace(initialiser_);
 500
 501     next_->Replace(context, statements);
 502
 503     if (assignment != NULL)
 504         statements = $$->*
 505             // XXX: this cast is quite incorrect
 506             $ CYIf($ CYIdentical($ CYTypeOf(dynamic_cast<CYExpression *>(initialiser_)), $S("undefined")), $$->*
 507                 $E(assignment)
 508             )->*
 509             statements;
 510 }
 511
 512 CYStatement *CYFunctionStatement::Replace(CYContext &context) {
 513     Replace_(context, true);
 514     return this;
 515 }
 516
 517 CYIdentifier *CYIdentifier::Replace(CYContext &context) {
 518     if (replace_ != NULL && replace_ != this)
 519         return replace_->Replace(context);
 520     replace_ = context.scope_->Lookup(context, this);
 521     return replace_;
 522 }
 523
 524 CYStatement *CYIf::Return() {
 525     CYImplicitReturn(true_);
 526     CYImplicitReturn(false_);
 527     return this;
 528 }
 529
 530 CYStatement *CYIf::Replace(CYContext &context) {
 531     context.Replace(test_);
 532     context.ReplaceAll(true_);
 533     context.ReplaceAll(false_);
 534     return this;
 535 }
 536
 537 CYFunctionParameter *CYIfComprehension::Parameter(CYContext &context) const {
 538     return NULL;
 539 }
 540
 541 CYStatement *CYIfComprehension::Replace(CYContext &context, CYStatement *statement) const {
 542     return $ CYIf(test_, CYComprehension::Replace(context, statement));
 543 }
 544
 545 CYStatement *CYImport::Replace(CYContext &context) {
 546     return $ CYVar($L1($L(module_->part_->Word(), $C1($V("require"), module_->Replace(context, "/")))));
 547 }
 548
 549 CYExpression *CYIndirect::Replace(CYContext &context) {
 550     return $M(rhs_, $S("$cyi"));
 551 }
 552
 553 CYExpression *CYIndirectMember::Replace(CYContext &context) {
 554     return $M($ CYIndirect(object_), property_);
 555 }
 556
 557 CYExpression *CYInfix::Replace(CYContext &context) {
 558     context.Replace(lhs_);
 559     context.Replace(rhs_);
 560     return this;
 561 }
 562
 563 CYStatement *CYLabel::Replace(CYContext &context) {
 564     context.Replace(statement_);
 565     return this;
 566 }
 567
 568 CYExpression *CYLambda::Replace(CYContext &context) {
 569     return $N2($V("Functor"), $ CYFunctionExpression(NULL, parameters_->Parameters(context), code_), parameters_->TypeSignature(context, typed_->Replace(context)));
 570 }
 571
 572 CYStatement *CYLetStatement::Replace(CYContext &context) {
 573     return $E($ CYCall(CYNonLocalize(context, $ CYFunctionExpression(NULL, declarations_->Parameter(context), code_)), declarations_->Argument(context)));
 574 }
 575
 576 CYString *CYModule::Replace(CYContext &context, const char *separator) const {
 577     if (next_ == NULL)
 578         return $ CYString(part_);
 579     return $ CYString($pool.strcat(next_->Replace(context, separator)->Value(), separator, part_->Word(), NULL));
 580 }
 581
 582 CYExpression *CYMultiply::Replace(CYContext &context) {
 583     CYInfix::Replace(context);
 584
 585     if (CYNumber *lhn = lhs_->Number(context))
 586         if (CYNumber *rhn = rhs_->Number(context))
 587             return $D(lhn->Value() * rhn->Value());
 588
 589     return this;
 590 }
 591
 592 namespace cy {
 593 namespace Syntax {
 594
 595 CYExpression *New::AddArgument(CYContext &context, CYExpression *value) {
 596     CYSetLast(arguments_) = $ CYArgument(value);
 597     return this;
 598 }
 599
 600 CYExpression *New::Replace(CYContext &context) {
 601     context.Replace(constructor_);
 602     arguments_->Replace(context);
 603     return this;
 604 }
 605
 606 } }
 607
 608 CYNumber *CYNull::Number(CYContext &context) {
 609     return $D(0);
 610 }
 611
 612 CYString *CYNull::String(CYContext &context) {
 613     return $S("null");
 614 }
 615
 616 CYNumber *CYNumber::Number(CYContext &context) {
 617     return this;
 618 }
 619
 620 CYString *CYNumber::String(CYContext &context) {
 621     // XXX: there is a precise algorithm for this
 622     return $S($pool.sprintf(24, "%.17g", Value()));
 623 }
 624
 625 CYExpression *CYObject::Replace(CYContext &context) {
 626     properties_->Replace(context);
 627     return this;
 628 }
 629
 630 CYExpression *CYParenthetical::Replace(CYContext &context) {
 631     return expression_;
 632 }
 633
 634 CYExpression *CYPostfix::Replace(CYContext &context) {
 635     context.Replace(lhs_);
 636     return this;
 637 }
 638
 639 CYExpression *CYPrefix::Replace(CYContext &context) {
 640     context.Replace(rhs_);
 641     return this;
 642 }
 643
 644 // XXX: this is evil evil black magic. don't ask, don't tell... don't believe!
 645 #define MappingSet "0etnirsoalfucdphmgyvbxTwSNECAFjDLkMOIBPqzRH$_WXUVGYKQJZ"
 646 //#define MappingSet "0abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_"
 647
 648 namespace {
 649     struct IdentifierUsageLess :
 650         std::binary_function<CYIdentifier *, CYIdentifier *, bool>
 651     {
 652         _finline bool operator ()(CYIdentifier *lhs, CYIdentifier *rhs) const {
 653             if (lhs->usage_ != rhs->usage_)
 654                 return lhs->usage_ > rhs->usage_;
 655             return lhs < rhs;
 656         }
 657     };
 658
 659     typedef std::set<CYIdentifier *, IdentifierUsageLess> IdentifierUsages;
 660 }
 661
 662 void CYScript::Replace(CYContext &context) {
 663     CYScope scope(true, context);
 664
 665     context.nextlocal_ = $ CYNonLocal();
 666     context.ReplaceAll(code_);
 667     context.NonLocal(code_);
 668
 669     scope.Close(context, code_);
 670
 671     size_t offset(0);
 672
 673     CYCStringSet external;
 674     for (CYIdentifierValueSet::const_iterator i(scope.identifiers_.begin()); i != scope.identifiers_.end(); ++i)
 675         external.insert((*i)->Word());
 676
 677     IdentifierUsages usages;
 678
 679     if (offset < context.rename_.size())
 680         CYForEach (i, context.rename_[offset].identifier_)
 681             usages.insert(i);
 682
 683     // XXX: totalling the probable occurrences and sorting by them would improve the result
 684     for (CYIdentifierUsageVector::const_iterator i(context.rename_.begin()); i != context.rename_.end(); ++i, ++offset) {
 685         //std::cout << *i << ":" << (*i)->offset_ << std::endl;
 686
 687         const char *name;
 688
 689         if (context.options_.verbose_)
 690             name = $pool.strcat("$", $pool.itoa(offset), NULL);
 691         else {
 692             char id[8];
 693             id[7] = '\0';
 694
 695           id:
 696             unsigned position(7), local(offset + 1);
 697
 698             do {
 699                 unsigned index(local % (sizeof(MappingSet) - 1));
 700                 local /= sizeof(MappingSet) - 1;
 701                 id[--position] = MappingSet[index];
 702             } while (local != 0);
 703
 704             if (external.find(id + position) != external.end()) {
 705                 ++offset;
 706                 goto id;
 707             }
 708
 709             name = $pool.strmemdup(id + position, 7 - position);
 710             // XXX: at some point, this could become a keyword
 711         }
 712
 713         CYForEach (identifier, i->identifier_)
 714             identifier->Set(name);
 715     }
 716 }
 717
 718 void CYProperty::Replace(CYContext &context) { $T()
 719     context.Replace(value_);
 720     next_->Replace(context);
 721     if (value_ == NULL)
 722         value_ = $U;
 723 }
 724
 725 CYStatement *CYReturn::Replace(CYContext &context) {
 726     if (context.nonlocal_ != NULL) {
 727         CYProperty *value(value_ == NULL ? NULL : $ CYProperty($S("$cyv"), value_));
 728         return $ cy::Syntax::Throw($ CYObject(
 729             $ CYProperty($S("$cyk"), $V(context.nonlocal_->Target(context)), value)
 730         ));
 731     }
 732
 733     context.Replace(value_);
 734     return this;
 735 }
 736
 737 CYExpression *CYRubyBlock::Replace(CYContext &context) {
 738     return call_->AddArgument(context, proc_->Replace(context));
 739 }
 740
 741 CYExpression *CYRubyBlock::AddArgument(CYContext &context, CYExpression *value) {
 742     return Replace(context)->AddArgument(context, value);
 743 }
 744
 745 CYExpression *CYRubyProc::Replace(CYContext &context) {
 746     CYFunctionExpression *function($ CYFunctionExpression(NULL, parameters_, code_));
 747     function = CYNonLocalize(context, function);
 748     function->implicit_ = true;
 749     return function;
 750 }
 751
 752 CYScope::CYScope(bool transparent, CYContext &context) :
 753     transparent_(transparent),
 754     parent_(context.scope_)
 755 {
 756     context.scope_ = this;
 757 }
 758
 759 void CYScope::Declare(CYContext &context, CYIdentifier *identifier, CYIdentifierFlags flags) {
 760     if (!transparent_ || flags == CYIdentifierArgument || flags == CYIdentifierCatch)
 761         internal_.insert(CYIdentifierAddressFlagsMap::value_type(identifier, flags));
 762     else if (parent_ != NULL)
 763         parent_->Declare(context, identifier, flags);
 764 }
 765
 766 CYIdentifier *CYScope::Lookup(CYContext &context, CYIdentifier *identifier) {
 767     std::pair<CYIdentifierValueSet::iterator, bool> insert(identifiers_.insert(identifier));
 768     return *insert.first;
 769 }
 770
 771 void CYScope::Merge(CYContext &context, CYIdentifier *identifier) {
 772     std::pair<CYIdentifierValueSet::iterator, bool> insert(identifiers_.insert(identifier));
 773     if (!insert.second) {
 774         if ((*insert.first)->offset_ < identifier->offset_)
 775             (*insert.first)->offset_ = identifier->offset_;
 776         identifier->replace_ = *insert.first;
 777         (*insert.first)->usage_ += identifier->usage_ + 1;
 778     }
 779 }
 780
 781 namespace {
 782     struct IdentifierOffset {
 783         size_t offset_;
 784         CYIdentifierFlags flags_;
 785         size_t usage_;
 786         CYIdentifier *identifier_;
 787
 788         IdentifierOffset(CYIdentifier *identifier, CYIdentifierFlags flags) :
 789             offset_(identifier->offset_),
 790             flags_(flags),
 791             usage_(identifier->usage_),
 792             identifier_(identifier)
 793         {
 794         }
 795     };
 796
 797     struct IdentifierOffsetLess :
 798         std::binary_function<const IdentifierOffset &, const IdentifierOffset &, bool>
 799     {
 800         _finline bool operator ()(const IdentifierOffset &lhs, const IdentifierOffset &rhs) const {
 801             if (lhs.offset_ != rhs.offset_)
 802                 return lhs.offset_ < rhs.offset_;
 803             if (lhs.flags_ != rhs.flags_)
 804                 return lhs.flags_ < rhs.flags_;
 805             /*if (lhs.usage_ != rhs.usage_)
 806                 return lhs.usage_ < rhs.usage_;*/
 807             return lhs.identifier_ < rhs.identifier_;
 808         }
 809     };
 810
 811     typedef std::set<IdentifierOffset, IdentifierOffsetLess> IdentifierOffsets;
 812 }
 813
 814 void CYScope::Close(CYContext &context, CYStatement *&statements) {
 815     context.scope_ = parent_;
 816
 817     if (parent_ == NULL)
 818         return;
 819
 820     CYDeclarations *last(NULL), *curr(NULL);
 821
 822     IdentifierOffsets offsets;
 823
 824     for (CYIdentifierAddressFlagsMap::const_iterator i(internal_.begin()); i != internal_.end(); ++i)
 825         if (i->second != CYIdentifierMagic)
 826             offsets.insert(IdentifierOffset(i->first, i->second));
 827
 828     size_t offset(0);
 829
 830     for (IdentifierOffsets::const_iterator i(offsets.begin()); i != offsets.end(); ++i) {
 831         if (i->flags_ == CYIdentifierVariable) {
 832             CYDeclarations *next($ CYDeclarations($ CYDeclaration(i->identifier_)));
 833             if (last == NULL)
 834                 last = next;
 835             if (curr != NULL)
 836                 curr->SetNext(next);
 837             curr = next;
 838         }
 839
 840         if (offset < i->offset_)
 841             offset = i->offset_;
 842         if (context.rename_.size() <= offset)
 843             context.rename_.resize(offset + 1);
 844
 845         CYIdentifierUsage &rename(context.rename_[offset++]);
 846         i->identifier_->SetNext(rename.identifier_);
 847         rename.identifier_ = i->identifier_;
 848         rename.usage_ += i->identifier_->usage_ + 1;
 849     }
 850
 851     if (last != NULL) {
 852         CYVar *var($ CYVar(last));
 853         var->SetNext(statements);
 854         statements = var;
 855     }
 856
 857     for (CYIdentifierValueSet::const_iterator i(identifiers_.begin()); i != identifiers_.end(); ++i)
 858         if (internal_.find(*i) == internal_.end()) {
 859             //std::cout << *i << '=' << offset << std::endl;
 860             if ((*i)->offset_ < offset)
 861                 (*i)->offset_ = offset;
 862             parent_->Merge(context, *i);
 863         }
 864 }
 865
 866 CYElementValue *CYSpan::Replace(CYContext &context) { $T(NULL)
 867     return $ CYElementValue(expression_, $ CYElementValue(string_, next_->Replace(context)));
 868 }
 869
 870 CYStatement *CYStatement::Return() {
 871     return this;
 872 }
 873
 874 CYString *CYString::Concat(CYContext &context, CYString *rhs) const {
 875     size_t size(size_ + rhs->size_);
 876     char *value($ char[size + 1]);
 877     memcpy(value, value_, size_);
 878     memcpy(value + size_, rhs->value_, rhs->size_);
 879     value[size] = '\0';
 880     return $S(value, size);
 881 }
 882
 883 CYNumber *CYString::Number(CYContext &context) {
 884     // XXX: there is a precise algorithm for this
 885     return NULL;
 886 }
 887
 888 CYString *CYString::String(CYContext &context) {
 889     return this;
 890 }
 891
 892 CYStatement *CYSwitch::Replace(CYContext &context) {
 893     context.Replace(value_);
 894     clauses_->Replace(context);
 895     return this;
 896 }
 897
 898 CYExpression *CYTemplate::Replace(CYContext &context) {
 899     return $C2($M($M($M($V("String"), $S("prototype")), $S("concat")), $S("apply")), $S(""), $ CYArray($ CYElementValue(string_, spans_->Replace(context))));
 900 }
 901
 902 CYExpression *CYThis::Replace(CYContext &context) {
 903     if (context.this_ != NULL)
 904         return $V(context.this_->Identifier(context));
 905     return this;
 906 }
 907
 908 namespace cy {
 909 namespace Syntax {
 910
 911 CYStatement *Throw::Replace(CYContext &context) {
 912     context.Replace(value_);
 913     return this;
 914 }
 915
 916 } }
 917
 918 CYExpression *CYTrivial::Replace(CYContext &context) {
 919     return this;
 920 }
 921
 922 CYNumber *CYTrue::Number(CYContext &context) {
 923     return $D(1);
 924 }
 925
 926 CYString *CYTrue::String(CYContext &context) {
 927     return $S("true");
 928 }
 929
 930 namespace cy {
 931 namespace Syntax {
 932
 933 CYStatement *Try::Replace(CYContext &context) {
 934     context.ReplaceAll(code_);
 935     catch_->Replace(context);
 936     finally_->Replace(context);
 937     return this;
 938 }
 939
 940 } }
 941
 942 CYExpression *CYTypeArrayOf::Replace_(CYContext &context, CYExpression *type) {
 943     return next_->Replace(context, $ CYCall($ CYDirectMember(type, $ CYString("arrayOf")), $ CYArgument(size_)));
 944 }
 945
 946 CYExpression *CYTypeBlockWith::Replace_(CYContext &context, CYExpression *type) {
 947     return next_->Replace(context, $ CYCall($ CYDirectMember(type, $ CYString("blockWith")), parameters_->Argument(context)));
 948 }
 949
 950 CYExpression *CYTypeConstant::Replace_(CYContext &context, CYExpression *type) {
 951     return next_->Replace(context, $ CYCall($ CYDirectMember(type, $ CYString("constant"))));
 952 }
 953
 954 CYStatement *CYTypeDefinition::Replace(CYContext &context) {
 955     return $E($ CYAssign($V(typed_->identifier_), typed_->Replace(context)));
 956 }
 957
 958 CYExpression *CYTypeError::Replace(CYContext &context) {
 959     _assert(false);
 960     return NULL;
 961 }
 962
 963 CYExpression *CYTypeModifier::Replace(CYContext &context, CYExpression *type) { $T(type)
 964     return Replace_(context, type);
 965 }
 966
 967 CYExpression *CYTypeFunctionWith::Replace_(CYContext &context, CYExpression *type) {
 968     return next_->Replace(context, $ CYCall($ CYDirectMember(type, $ CYString("functionWith")), parameters_->Argument(context)));
 969 }
 970
 971 CYExpression *CYTypeLong::Replace(CYContext &context) {
 972     return $ CYCall($ CYDirectMember(specifier_->Replace(context), $ CYString("long")));
 973 }
 974
 975 CYExpression *CYTypePointerTo::Replace_(CYContext &context, CYExpression *type) {
 976     return next_->Replace(context, $ CYCall($ CYDirectMember(type, $ CYString("pointerTo"))));
 977 }
 978
 979 CYExpression *CYTypeShort::Replace(CYContext &context) {
 980     return $ CYCall($ CYDirectMember(specifier_->Replace(context), $ CYString("short")));
 981 }
 982
 983 CYExpression *CYTypeSigned::Replace(CYContext &context) {
 984     return $ CYCall($ CYDirectMember(specifier_->Replace(context), $ CYString("signed")));
 985 }
 986
 987 CYExpression *CYTypeUnsigned::Replace(CYContext &context) {
 988     return $ CYCall($ CYDirectMember(specifier_->Replace(context), $ CYString("unsigned")));
 989 }
 990
 991 CYExpression *CYTypeVariable::Replace(CYContext &context) {
 992     return $V(name_);
 993 }
 994
 995 CYExpression *CYTypeVoid::Replace(CYContext &context) {
 996     return $N1($V("Type"), $ CYString("v"));
 997 }
 998
 999 CYExpression *CYTypeVolatile::Replace_(CYContext &context, CYExpression *type) {
1000     return next_->Replace(context, $ CYCall($ CYDirectMember(type, $ CYString("volatile"))));
1001 }
1002
1003 CYExpression *CYTypedIdentifier::Replace(CYContext &context) {
1004     return modifier_->Replace(context, specifier_->Replace(context));
1005 }
1006
1007 CYTypeFunctionWith *CYTypedIdentifier::Function() {
1008     CYTypeModifier **modifier(&modifier_);
1009     if (*modifier == NULL)
1010         return NULL;
1011     while ((*modifier)->next_ != NULL)
1012         modifier = &(*modifier)->next_;
1013     CYTypeFunctionWith *function((*modifier)->Function());
1014     if (function == NULL)
1015         return NULL;
1016     *modifier = NULL;
1017     return function;
1018 }
1019
1020 CYArgument *CYTypedParameter::Argument(CYContext &context) { $T(NULL)
1021     return $ CYArgument(typed_->Replace(context), next_->Argument(context));
1022 }
1023
1024 CYFunctionParameter *CYTypedParameter::Parameters(CYContext &context) { $T(NULL)
1025     return $ CYFunctionParameter($ CYDeclaration(typed_->identifier_ ?: context.Unique()), next_->Parameters(context));
1026 }
1027
1028 CYExpression *CYTypedParameter::TypeSignature(CYContext &context, CYExpression *prefix) { $T(prefix)
1029     return next_->TypeSignature(context, $ CYAdd(prefix, typed_->Replace(context)));
1030 }
1031
1032 CYStatement *CYVar::Replace(CYContext &context) {
1033     declarations_->Replace(context);
1034     if (CYExpression *expression = declarations_->Expression(context))
1035         return $E(expression);
1036     return $ CYEmpty();
1037 }
1038
1039 CYExpression *CYVariable::Replace(CYContext &context) {
1040     context.Replace(name_);
1041     return this;
1042 }
1043
1044 CYFunctionParameter *CYVariable::Parameter() const {
1045     return $ CYFunctionParameter($ CYDeclaration(name_));
1046 }
1047
1048 CYStatement *CYWhile::Replace(CYContext &context) {
1049     context.Replace(test_);
1050     context.ReplaceAll(code_);
1051     return this;
1052 }
1053
1054 CYStatement *CYWith::Replace(CYContext &context) {
1055     context.Replace(scope_);
1056     context.ReplaceAll(code_);
1057     return this;
1058 }
1059
1060 CYExpression *CYWord::ClassName(CYContext &context, bool object) {
1061     CYString *name($S(this));
1062     if (object)
1063         return $C1($V("objc_getClass"), name);
1064     else
1065         return name;
1066 }