Replace.cpp

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