Replace.cpp

   1 /* Cycript - Optimizing JavaScript Compiler/Runtime
   2  * Copyright (C) 2009-2012  Jay Freeman (saurik)
   3 */
   4
   5 /* GNU Lesser General Public License, Version 3 {{{ */
   6 /*
   7  * Cycript is free software: you can redistribute it and/or modify it under
   8  * the terms of the GNU Lesser General Public License as published by the
   9  * Free Software Foundation, either version 3 of the License, or (at your
  10  * option) any later version.
  11  *
  12  * Cycript is distributed in the hope that it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  15  * License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with Cycript.  If not, see <http://www.gnu.org/licenses/>.
  19 **/
  20 /* }}} */
  21
  22 #include "Parser.hpp"
  23 #include "Replace.hpp"
  24
  25 #include <iomanip>
  26
  27 CYFunctionExpression *CYNonLocalize(CYContext &context, CYFunctionExpression *function) {
  28     function->nonlocal_ = context.nextlocal_;
  29     return function;
  30 }
  31
  32 CYExpression *CYAdd::Replace(CYContext &context) {
  33     CYInfix::Replace(context);
  34
  35     CYExpression *lhp(lhs_->Primitive(context));
  36     CYExpression *rhp(rhs_->Primitive(context));
  37
  38     CYString *lhs(dynamic_cast<CYString *>(lhp));
  39     CYString *rhs(dynamic_cast<CYString *>(rhp));
  40
  41     if (lhs != NULL || rhs != NULL) {
  42         if (lhs == NULL) {
  43             lhs = lhp->String(context);
  44             if (lhs == NULL)
  45                 return this;
  46         } else if (rhs == NULL) {
  47             rhs = rhp->String(context);
  48             if (rhs == NULL)
  49                 return this;
  50         }
  51
  52         return lhs->Concat(context, rhs);
  53     }
  54
  55     if (CYNumber *lhn = lhp->Number(context))
  56         if (CYNumber *rhn = rhp->Number(context))
  57             return $D(lhn->Value() + rhn->Value());
  58
  59     return this;
  60 }
  61
  62 CYExpression *CYAddressOf::Replace(CYContext &context) {
  63     return $C0($M(rhs_, $S("$cya")));
  64 }
  65
  66 CYArgument *CYArgument::Replace(CYContext &context) { $T(NULL)
  67     context.Replace(value_);
  68     next_ = next_->Replace(context);
  69
  70     if (value_ == NULL) {
  71         if (next_ == NULL)
  72             return NULL;
  73         else
  74             value_ = $U;
  75     }
  76
  77     return this;
  78 }
  79
  80 CYExpression *CYArray::Replace(CYContext &context) {
  81     elements_->Replace(context);
  82     return this;
  83 }
  84
  85 CYExpression *CYArrayComprehension::Replace(CYContext &context) {
  86     CYVariable *cyv($V("$cyv"));
  87
  88     return $C0($F(NULL, $P1($L("$cyv"), comprehensions_->Parameters(context)), $$->*
  89         $E($ CYAssign(cyv, $ CYArray()))->*
  90         comprehensions_->Replace(context, $E($C1($M(cyv, $S("push")), expression_)))->*
  91         $ CYReturn(cyv)
  92     ));
  93 }
  94
  95 CYExpression *CYAssignment::Replace(CYContext &context) {
  96     context.Replace(lhs_);
  97     context.Replace(rhs_);
  98     return this;
  99 }
 100
 101 CYStatement *CYBlock::Replace(CYContext &context) {
 102     context.ReplaceAll(statements_);
 103     if (statements_ == NULL)
 104         return $ CYEmpty();
 105     return this;
 106 }
 107
 108 CYStatement *CYBreak::Replace(CYContext &context) {
 109     return this;
 110 }
 111
 112 CYExpression *CYCall::AddArgument(CYContext &context, CYExpression *value) {
 113     CYArgument **argument(&arguments_);
 114     while (*argument != NULL)
 115         argument = &(*argument)->next_;
 116     *argument = $ CYArgument(value);
 117     return this;
 118 }
 119
 120 CYExpression *CYCall::Replace(CYContext &context) {
 121     context.Replace(function_);
 122     arguments_->Replace(context);
 123     return this;
 124 }
 125
 126 namespace cy {
 127 namespace Syntax {
 128
 129 void Catch::Replace(CYContext &context) { $T()
 130     CYScope scope(true, context, code_.statements_);
 131
 132     context.Replace(name_);
 133     context.scope_->Declare(context, name_, CYIdentifierCatch);
 134
 135     code_.Replace(context);
 136     scope.Close();
 137 }
 138
 139 } }
 140
 141 void CYClause::Replace(CYContext &context) { $T()
 142     context.Replace(case_);
 143     context.ReplaceAll(statements_);
 144     next_->Replace(context);
 145 }
 146
 147 CYStatement *CYComment::Replace(CYContext &context) {
 148     return this;
 149 }
 150
 151 CYExpression *CYCompound::Replace(CYContext &context) {
 152     context.ReplaceAll(expressions_);
 153     if (expressions_ == NULL)
 154         return NULL;
 155     return this;
 156 }
 157
 158 CYExpression *CYCompound::Primitive(CYContext &context) {
 159     CYExpression *expression(expressions_);
 160     if (expression == NULL)
 161         return NULL;
 162     while (expression->next_ != NULL)
 163         expression = expression->next_;
 164     return expression->Primitive(context);
 165 }
 166
 167 CYFunctionParameter *CYComprehension::Parameters(CYContext &context) const { $T(NULL)
 168     CYFunctionParameter *next(next_->Parameters(context));
 169     if (CYFunctionParameter *parameter = Parameter(context)) {
 170         parameter->SetNext(next);
 171         return parameter;
 172     } else
 173         return next;
 174 }
 175
 176 CYStatement *CYComprehension::Replace(CYContext &context, CYStatement *statement) const {
 177     return next_ == NULL ? statement : next_->Replace(context, statement);
 178 }
 179
 180 CYExpression *CYCondition::Replace(CYContext &context) {
 181     context.Replace(test_);
 182     context.Replace(true_);
 183     context.Replace(false_);
 184     return this;
 185 }
 186
 187 void CYContext::NonLocal(CYStatement *&statements) {
 188     CYContext &context(*this);
 189
 190     if (nextlocal_ != NULL && nextlocal_->identifier_ != NULL) {
 191         CYIdentifier *cye($I("$cye")->Replace(context));
 192         CYIdentifier *unique(nextlocal_->identifier_->Replace(context));
 193
 194         CYStatement *declare(
 195             $ CYVar($L1($ CYDeclaration(unique, $ CYObject()))));
 196
 197         cy::Syntax::Catch *rescue(
 198             $ cy::Syntax::Catch(cye, $$->*
 199                 $ CYIf($ CYIdentical($M($V(cye), $S("$cyk")), $V(unique)), $$->*
 200                     $ CYReturn($M($V(cye), $S("$cyv"))))->*
 201                 $ cy::Syntax::Throw($V(cye))));
 202
 203         context.Replace(declare);
 204         rescue->Replace(context);
 205
 206         statements = $$->*
 207             declare->*
 208             $ cy::Syntax::Try(statements, rescue, NULL);
 209     }
 210 }
 211
 212 CYIdentifier *CYContext::Unique() {
 213     return $ CYIdentifier(apr_psprintf($pool, "$cy%u", unique_++));
 214 }
 215
 216 CYStatement *CYContinue::Replace(CYContext &context) {
 217     return this;
 218 }
 219
 220 CYStatement *CYDebugger::Replace(CYContext &context) {
 221     return this;
 222 }
 223
 224 CYAssignment *CYDeclaration::Assignment(CYContext &context) {
 225     if (initialiser_ == NULL)
 226         return NULL;
 227
 228     CYAssignment *value($ CYAssign(Variable(context), initialiser_));
 229     initialiser_ = NULL;
 230     return value;
 231 }
 232
 233 CYVariable *CYDeclaration::Variable(CYContext &context) {
 234     return $V(identifier_);
 235 }
 236
 237 CYStatement *CYDeclaration::ForEachIn(CYContext &context, CYExpression *value) {
 238     return $ CYVar($L1($ CYDeclaration(identifier_, value)));
 239 }
 240
 241 CYExpression *CYDeclaration::Replace(CYContext &context) {
 242     context.Replace(identifier_);
 243     context.scope_->Declare(context, identifier_, CYIdentifierVariable);
 244     return Variable(context);
 245 }
 246
 247 void CYDeclarations::Replace(CYContext &context) { $T()
 248     declaration_->Replace(context);
 249     next_->Replace(context);
 250 }
 251
 252 CYProperty *CYDeclarations::Property(CYContext &context) { $T(NULL)
 253     return $ CYProperty(declaration_->identifier_, declaration_->initialiser_, next_->Property(context));
 254 }
 255
 256 CYFunctionParameter *CYDeclarations::Parameter(CYContext &context) { $T(NULL)
 257     return $ CYFunctionParameter($ CYDeclaration(declaration_->identifier_), next_->Parameter(context));
 258 }
 259
 260 CYArgument *CYDeclarations::Argument(CYContext &context) { $T(NULL)
 261     return $ CYArgument(declaration_->initialiser_, next_->Argument(context));
 262 }
 263
 264 CYCompound *CYDeclarations::Compound(CYContext &context) { $T(NULL)
 265     CYCompound *compound(next_->Compound(context) ?: $ CYCompound());
 266     if (CYAssignment *assignment = declaration_->Assignment(context))
 267         compound->AddPrev(assignment);
 268     return compound;
 269 }
 270
 271 CYExpression *CYDirectMember::Replace(CYContext &context) {
 272     context.Replace(object_);
 273     context.Replace(property_);
 274     return this;
 275 }
 276
 277 CYStatement *CYDoWhile::Replace(CYContext &context) {
 278     context.Replace(test_);
 279     context.Replace(code_);
 280     return this;
 281 }
 282
 283 void CYElement::Replace(CYContext &context) { $T()
 284     context.Replace(value_);
 285     next_->Replace(context);
 286 }
 287
 288 CYStatement *CYEmpty::Replace(CYContext &context) {
 289     return NULL;
 290 }
 291
 292 CYStatement *CYExpress::Replace(CYContext &context) {
 293     while (CYExpress *express = dynamic_cast<CYExpress *>(next_)) {
 294         CYCompound *compound(dynamic_cast<CYCompound *>(express->expression_));
 295         if (compound == NULL)
 296             compound = $ CYCompound(express->expression_);
 297         compound->AddPrev(expression_);
 298         expression_ = compound;
 299         SetNext(express->next_);
 300     }
 301
 302     context.Replace(expression_);
 303     if (expression_ == NULL)
 304         return $ CYEmpty();
 305
 306     return this;
 307 }
 308
 309 CYExpression *CYExpression::AddArgument(CYContext &context, CYExpression *value) {
 310     return $C1(this, value);
 311 }
 312
 313 CYExpression *CYExpression::ClassName(CYContext &context, bool object) {
 314     return this;
 315 }
 316
 317 CYStatement *CYExpression::ForEachIn(CYContext &context, CYExpression *value) {
 318     return $E($ CYAssign(this, value));
 319 }
 320
 321 CYAssignment *CYExpression::Assignment(CYContext &context) {
 322     return NULL;
 323 }
 324
 325 CYNumber *CYFalse::Number(CYContext &context) {
 326     return $D(0);
 327 }
 328
 329 CYString *CYFalse::String(CYContext &context) {
 330     return $S("false");
 331 }
 332
 333 CYExpression *CYFatArrow::Replace(CYContext &context) {
 334     CYFunctionExpression *function($ CYFunctionExpression(NULL, parameters_, code_));
 335     function->this_.SetNext(context.this_);
 336     return function;
 337 }
 338
 339 void CYFinally::Replace(CYContext &context) { $T()
 340     code_.Replace(context);
 341 }
 342
 343 CYStatement *CYFor::Replace(CYContext &context) {
 344     context.Replace(initialiser_);
 345     context.Replace(test_);
 346     context.Replace(increment_);
 347     context.Replace(code_);
 348     return this;
 349 }
 350
 351 CYCompound *CYForDeclarations::Replace(CYContext &context) {
 352     declarations_->Replace(context);
 353     return declarations_->Compound(context);
 354 }
 355
 356 // XXX: this still feels highly suboptimal
 357 CYStatement *CYForIn::Replace(CYContext &context) {
 358     if (CYAssignment *assignment = initialiser_->Assignment(context))
 359         return $ CYBlock($$->*
 360             $E(assignment)->*
 361             this
 362         );
 363
 364     context.Replace(initialiser_);
 365     context.Replace(set_);
 366     context.Replace(code_);
 367     return this;
 368 }
 369
 370 CYFunctionParameter *CYForInComprehension::Parameter(CYContext &context) const {
 371     return $ CYFunctionParameter($ CYDeclaration(name_));
 372 }
 373
 374 CYStatement *CYForInComprehension::Replace(CYContext &context, CYStatement *statement) const {
 375     return $ CYForIn($V(name_), set_, CYComprehension::Replace(context, statement));
 376 }
 377
 378 CYStatement *CYForOf::Replace(CYContext &context) {
 379     if (CYAssignment *assignment = initialiser_->Assignment(context))
 380         return $ CYBlock($$->*
 381             $E(assignment)->*
 382             this
 383         );
 384
 385     CYIdentifier *cys($I("$cys")), *cyt($I("$cyt"));
 386
 387     return $ CYLetStatement($L2($ CYDeclaration(cys, set_), $ CYDeclaration(cyt)), $$->*
 388         $ CYForIn($V(cyt), $V(cys), $ CYBlock($$->*
 389             initialiser_->ForEachIn(context, $M($V(cys), $V(cyt)))->*
 390             code_
 391         ))
 392     );
 393 }
 394
 395 CYFunctionParameter *CYForOfComprehension::Parameter(CYContext &context) const {
 396     return $ CYFunctionParameter($ CYDeclaration(name_));
 397 }
 398
 399 CYStatement *CYForOfComprehension::Replace(CYContext &context, CYStatement *statement) const {
 400     CYIdentifier *cys($I("cys"));
 401
 402     return $E($C0($F(NULL, $P1($L("$cys")), $$->*
 403         $E($ CYAssign($V(cys), set_))->*
 404         $ CYForIn($V(name_), $V(cys), $ CYBlock($$->*
 405             $E($ CYAssign($V(name_), $M($V(cys), $V(name_))))->*
 406             CYComprehension::Replace(context, statement)
 407         ))
 408     )));
 409 }
 410
 411 void CYFunction::Inject(CYContext &context) {
 412     context.Replace(name_);
 413     context.scope_->Declare(context, name_, CYIdentifierOther);
 414 }
 415
 416 void CYFunction::Replace_(CYContext &context, bool outer) {
 417     if (outer)
 418         Inject(context);
 419
 420     CYThisScope *_this(context.this_);
 421     context.this_ = CYGetLast(&this_);
 422
 423     CYNonLocal *nonlocal(context.nonlocal_);
 424     CYNonLocal *nextlocal(context.nextlocal_);
 425
 426     bool localize;
 427     if (nonlocal_ != NULL) {
 428         localize = false;
 429         context.nonlocal_ = nonlocal_;
 430     } else {
 431         localize = true;
 432         nonlocal_ = $ CYNonLocal();
 433         context.nextlocal_ = nonlocal_;
 434     }
 435
 436     CYScope scope(!localize, context, code_.statements_);
 437
 438     if (!outer && name_ != NULL)
 439         Inject(context);
 440
 441     parameters_->Replace(context, code_);
 442     code_.Replace(context);
 443
 444     if (CYIdentifier *identifier = this_.identifier_)
 445         code_.statements_ = $$->*
 446             $ CYVar($L1($ CYDeclaration(identifier, $ CYThis())))->*
 447             code_.statements_;
 448
 449     if (localize)
 450         context.NonLocal(code_.statements_);
 451
 452     context.nextlocal_ = nextlocal;
 453     context.nonlocal_ = nonlocal;
 454
 455     context.this_ = _this;
 456
 457     scope.Close();
 458 }
 459
 460 CYExpression *CYFunctionExpression::Replace(CYContext &context) {
 461     Replace_(context, false);
 462     return this;
 463 }
 464
 465 void CYFunctionParameter::Replace(CYContext &context, CYBlock &code) { $T()
 466     CYAssignment *assignment(initialiser_->Assignment(context));
 467     context.Replace(initialiser_);
 468
 469     next_->Replace(context, code);
 470
 471     if (assignment != NULL)
 472         // XXX: this cast is quite incorrect
 473         code.AddPrev($ CYIf($ CYIdentical($ CYTypeOf(dynamic_cast<CYExpression *>(initialiser_)), $S("undefined")), $$->*
 474             $E(assignment)
 475         ));
 476 }
 477
 478 CYStatement *CYFunctionStatement::Replace(CYContext &context) {
 479     Replace_(context, true);
 480     return this;
 481 }
 482
 483 CYIdentifier *CYIdentifier::Replace(CYContext &context) {
 484     if (replace_ != NULL && replace_ != this)
 485         return replace_->Replace(context);
 486     replace_ = context.scope_->Lookup(context, this);
 487     return replace_;
 488 }
 489
 490 CYStatement *CYIf::Replace(CYContext &context) {
 491     context.Replace(test_);
 492     context.Replace(true_);
 493     context.Replace(false_);
 494     return this;
 495 }
 496
 497 CYFunctionParameter *CYIfComprehension::Parameter(CYContext &context) const {
 498     return NULL;
 499 }
 500
 501 CYStatement *CYIfComprehension::Replace(CYContext &context, CYStatement *statement) const {
 502     return $ CYIf(test_, CYComprehension::Replace(context, statement));
 503 }
 504
 505 CYExpression *CYIndirect::Replace(CYContext &context) {
 506     return $M(rhs_, $S("$cyi"));
 507 }
 508
 509 CYExpression *CYIndirectMember::Replace(CYContext &context) {
 510     return $M($ CYIndirect(object_), property_);
 511 }
 512
 513 CYExpression *CYInfix::Replace(CYContext &context) {
 514     context.Replace(lhs_);
 515     context.Replace(rhs_);
 516     return this;
 517 }
 518
 519 CYStatement *CYLabel::Replace(CYContext &context) {
 520     context.Replace(statement_);
 521     return this;
 522 }
 523
 524 CYStatement *CYLetStatement::Replace(CYContext &context) {
 525     return $E($ CYCall(CYNonLocalize(context, $ CYFunctionExpression(NULL, declarations_->Parameter(context), code_)), declarations_->Argument(context)));
 526 }
 527
 528 namespace cy {
 529 namespace Syntax {
 530
 531 CYExpression *New::AddArgument(CYContext &context, CYExpression *value) {
 532     CYSetLast(arguments_) = $ CYArgument(value);
 533     return this;
 534 }
 535
 536 CYExpression *New::Replace(CYContext &context) {
 537     context.Replace(constructor_);
 538     arguments_->Replace(context);
 539     return this;
 540 }
 541
 542 } }
 543
 544 CYNumber *CYNull::Number(CYContext &context) {
 545     return $D(0);
 546 }
 547
 548 CYString *CYNull::String(CYContext &context) {
 549     return $S("null");
 550 }
 551
 552 CYNumber *CYNumber::Number(CYContext &context) {
 553     return this;
 554 }
 555
 556 CYString *CYNumber::String(CYContext &context) {
 557     // XXX: there is a precise algorithm for this
 558     return $S(apr_psprintf($pool, "%.17g", Value()));
 559 }
 560
 561 CYExpression *CYObject::Replace(CYContext &context) {
 562     properties_->Replace(context);
 563     return this;
 564 }
 565
 566 CYExpression *CYPostfix::Replace(CYContext &context) {
 567     context.Replace(lhs_);
 568     return this;
 569 }
 570
 571 CYExpression *CYPrefix::Replace(CYContext &context) {
 572     context.Replace(rhs_);
 573     return this;
 574 }
 575
 576 // XXX: this is evil evil black magic. don't ask, don't tell... don't believe!
 577 #define MappingSet "0etnirsoalfucdphmgyvbxTwSNECAFjDLkMOIBPqzRH$_WXUVGYKQJZ"
 578 //#define MappingSet "0abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_"
 579
 580 namespace {
 581     struct IdentifierUsageLess :
 582         std::binary_function<CYIdentifier *, CYIdentifier *, bool>
 583     {
 584         _finline bool operator ()(CYIdentifier *lhs, CYIdentifier *rhs) const {
 585             if (lhs->usage_ != rhs->usage_)
 586                 return lhs->usage_ > rhs->usage_;
 587             return lhs < rhs;
 588         }
 589     };
 590
 591     typedef std::set<CYIdentifier *, IdentifierUsageLess> IdentifierUsages;
 592 }
 593
 594 void CYProgram::Replace(CYContext &context) {
 595     CYScope scope(true, context, statements_);
 596
 597     context.nextlocal_ = $ CYNonLocal();
 598     context.ReplaceAll(statements_);
 599     context.NonLocal(statements_);
 600
 601     scope.Close();
 602
 603     size_t offset(0);
 604
 605     CYCStringSet external;
 606     for (CYIdentifierValueSet::const_iterator i(scope.identifiers_.begin()); i != scope.identifiers_.end(); ++i)
 607         external.insert((*i)->Word());
 608
 609     IdentifierUsages usages;
 610
 611     if (offset < context.rename_.size())
 612         CYForEach (i, context.rename_[offset].identifier_)
 613             usages.insert(i);
 614
 615     // XXX: totalling the probable occurrences and sorting by them would improve the result
 616     for (CYIdentifierUsageVector::const_iterator i(context.rename_.begin()); i != context.rename_.end(); ++i, ++offset) {
 617         //std::cout << *i << ":" << (*i)->offset_ << std::endl;
 618
 619         const char *name;
 620
 621         if (context.options_.verbose_)
 622             name = apr_psprintf($pool, "$%"APR_SIZE_T_FMT"", offset);
 623         else {
 624             char id[8];
 625             id[7] = '\0';
 626
 627           id:
 628             unsigned position(7), local(offset + 1);
 629
 630             do {
 631                 unsigned index(local % (sizeof(MappingSet) - 1));
 632                 local /= sizeof(MappingSet) - 1;
 633                 id[--position] = MappingSet[index];
 634             } while (local != 0);
 635
 636             if (external.find(id + position) != external.end()) {
 637                 ++offset;
 638                 goto id;
 639             }
 640
 641             name = apr_pstrmemdup($pool, id + position, 7 - position);
 642             // XXX: at some point, this could become a keyword
 643         }
 644
 645         CYForEach (identifier, i->identifier_)
 646             identifier->Set(name);
 647     }
 648 }
 649
 650 void CYProperty::Replace(CYContext &context) { $T()
 651     context.Replace(value_);
 652     next_->Replace(context);
 653     if (value_ == NULL)
 654         value_ = $U;
 655 }
 656
 657 CYStatement *CYReturn::Replace(CYContext &context) {
 658     if (context.nonlocal_ != NULL) {
 659         CYProperty *value(value_ == NULL ? NULL : $ CYProperty($S("$cyv"), value_));
 660         return $ cy::Syntax::Throw($ CYObject(
 661             $ CYProperty($S("$cyk"), $V(context.nonlocal_->Target(context)), value)
 662         ));
 663     }
 664
 665     context.Replace(value_);
 666     return this;
 667 }
 668
 669 CYExpression *CYRubyBlock::Replace(CYContext &context) {
 670     // XXX: this needs to do something much more epic to handle return
 671     return call_->AddArgument(context, proc_->Replace(context));
 672 }
 673
 674 CYExpression *CYRubyProc::Replace(CYContext &context) {
 675     return CYNonLocalize(context, $ CYFunctionExpression(NULL, parameters_, code_));
 676 }
 677
 678 CYScope::CYScope(bool transparent, CYContext &context, CYStatement *&statements) :
 679     transparent_(transparent),
 680     context_(context),
 681     statements_(statements),
 682     parent_(context.scope_)
 683 {
 684     context_.scope_ = this;
 685 }
 686
 687 CYScope::~CYScope() {
 688 }
 689
 690 void CYScope::Close() {
 691     context_.scope_ = parent_;
 692     Scope(context_, statements_);
 693 }
 694
 695 void CYScope::Declare(CYContext &context, CYIdentifier *identifier, CYIdentifierFlags flags) {
 696     if (!transparent_ || flags == CYIdentifierArgument || flags == CYIdentifierCatch)
 697         internal_.insert(CYIdentifierAddressFlagsMap::value_type(identifier, flags));
 698     else if (parent_ != NULL)
 699         parent_->Declare(context, identifier, flags);
 700 }
 701
 702 CYIdentifier *CYScope::Lookup(CYContext &context, CYIdentifier *identifier) {
 703     std::pair<CYIdentifierValueSet::iterator, bool> insert(identifiers_.insert(identifier));
 704     return *insert.first;
 705 }
 706
 707 void CYScope::Merge(CYContext &context, CYIdentifier *identifier) {
 708     std::pair<CYIdentifierValueSet::iterator, bool> insert(identifiers_.insert(identifier));
 709     if (!insert.second) {
 710         if ((*insert.first)->offset_ < identifier->offset_)
 711             (*insert.first)->offset_ = identifier->offset_;
 712         identifier->replace_ = *insert.first;
 713         (*insert.first)->usage_ += identifier->usage_ + 1;
 714     }
 715 }
 716
 717 namespace {
 718     struct IdentifierOffset {
 719         size_t offset_;
 720         CYIdentifierFlags flags_;
 721         size_t usage_;
 722         CYIdentifier *identifier_;
 723
 724         IdentifierOffset(CYIdentifier *identifier, CYIdentifierFlags flags) :
 725             offset_(identifier->offset_),
 726             flags_(flags),
 727             usage_(identifier->usage_),
 728             identifier_(identifier)
 729         {
 730         }
 731     };
 732
 733     struct IdentifierOffsetLess :
 734         std::binary_function<const IdentifierOffset &, const IdentifierOffset &, bool>
 735     {
 736         _finline bool operator ()(const IdentifierOffset &lhs, const IdentifierOffset &rhs) const {
 737             if (lhs.offset_ != rhs.offset_)
 738                 return lhs.offset_ < rhs.offset_;
 739             if (lhs.flags_ != rhs.flags_)
 740                 return lhs.flags_ < rhs.flags_;
 741             /*if (lhs.usage_ != rhs.usage_)
 742                 return lhs.usage_ < rhs.usage_;*/
 743             return lhs.identifier_ < rhs.identifier_;
 744         }
 745     };
 746
 747     typedef std::set<IdentifierOffset, IdentifierOffsetLess> IdentifierOffsets;
 748 }
 749
 750 void CYScope::Scope(CYContext &context, CYStatement *&statements) {
 751     if (parent_ == NULL)
 752         return;
 753
 754     CYDeclarations *last(NULL), *curr(NULL);
 755
 756     IdentifierOffsets offsets;
 757
 758     for (CYIdentifierAddressFlagsMap::const_iterator i(internal_.begin()); i != internal_.end(); ++i)
 759         if (i->second != CYIdentifierMagic)
 760             offsets.insert(IdentifierOffset(i->first, i->second));
 761
 762     size_t offset(0);
 763
 764     for (IdentifierOffsets::const_iterator i(offsets.begin()); i != offsets.end(); ++i) {
 765         if (i->flags_ == CYIdentifierVariable) {
 766             CYDeclarations *next($ CYDeclarations($ CYDeclaration(i->identifier_)));
 767             if (last == NULL)
 768                 last = next;
 769             if (curr != NULL)
 770                 curr->SetNext(next);
 771             curr = next;
 772         }
 773
 774         if (offset < i->offset_)
 775             offset = i->offset_;
 776         if (context.rename_.size() <= offset)
 777             context.rename_.resize(offset + 1);
 778
 779         CYIdentifierUsage &rename(context.rename_[offset++]);
 780         i->identifier_->SetNext(rename.identifier_);
 781         rename.identifier_ = i->identifier_;
 782         rename.usage_ += i->identifier_->usage_ + 1;
 783     }
 784
 785     if (last != NULL) {
 786         CYVar *var($ CYVar(last));
 787         var->SetNext(statements);
 788         statements = var;
 789     }
 790
 791     for (CYIdentifierValueSet::const_iterator i(identifiers_.begin()); i != identifiers_.end(); ++i)
 792         if (internal_.find(*i) == internal_.end()) {
 793             //std::cout << *i << '=' << offset << std::endl;
 794             if ((*i)->offset_ < offset)
 795                 (*i)->offset_ = offset;
 796             parent_->Merge(context, *i);
 797         }
 798 }
 799
 800 CYString *CYString::Concat(CYContext &context, CYString *rhs) const {
 801     size_t size(size_ + rhs->size_);
 802     char *value($ char[size + 1]);
 803     memcpy(value, value_, size_);
 804     memcpy(value + size_, rhs->value_, rhs->size_);
 805     value[size] = '\0';
 806     return $S(value, size);
 807 }
 808
 809 CYNumber *CYString::Number(CYContext &context) {
 810     // XXX: there is a precise algorithm for this
 811     return NULL;
 812 }
 813
 814 CYString *CYString::String(CYContext &context) {
 815     return this;
 816 }
 817
 818 CYStatement *CYSwitch::Replace(CYContext &context) {
 819     context.Replace(value_);
 820     clauses_->Replace(context);
 821     return this;
 822 }
 823
 824 CYExpression *CYThis::Replace(CYContext &context) {
 825     if (context.this_ != NULL)
 826         return $V(context.this_->Identifier(context));
 827     return this;
 828 }
 829
 830 namespace cy {
 831 namespace Syntax {
 832
 833 CYStatement *Throw::Replace(CYContext &context) {
 834     context.Replace(value_);
 835     return this;
 836 }
 837
 838 } }
 839
 840 CYExpression *CYTrivial::Replace(CYContext &context) {
 841     return this;
 842 }
 843
 844 CYNumber *CYTrue::Number(CYContext &context) {
 845     return $D(1);
 846 }
 847
 848 CYString *CYTrue::String(CYContext &context) {
 849     return $S("true");
 850 }
 851
 852 namespace cy {
 853 namespace Syntax {
 854
 855 CYStatement *Try::Replace(CYContext &context) {
 856     code_.Replace(context);
 857     catch_->Replace(context);
 858     finally_->Replace(context);
 859     return this;
 860 }
 861
 862 } }
 863
 864 CYStatement *CYVar::Replace(CYContext &context) {
 865     declarations_->Replace(context);
 866     return $E(declarations_->Compound(context));
 867 }
 868
 869 CYExpression *CYVariable::Replace(CYContext &context) {
 870     context.Replace(name_);
 871     return this;
 872 }
 873
 874 CYStatement *CYWhile::Replace(CYContext &context) {
 875     context.Replace(test_);
 876     context.Replace(code_);
 877     return this;
 878 }
 879
 880 CYStatement *CYWith::Replace(CYContext &context) {
 881     context.Replace(scope_);
 882     context.Replace(code_);
 883     return this;
 884 }
 885
 886 CYExpression *CYWord::ClassName(CYContext &context, bool object) {
 887     CYString *name($S(this));
 888     if (object)
 889         return $C1($V("objc_getClass"), name);
 890     else
 891         return name;
 892 }