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 CYStatement *CYContinue::Replace(CYContext &context) {
 176     return this;
 177 }
 178
 179 CYAssignment *CYDeclaration::Assignment(CYContext &context) {
 180     CYExpression *variable(Replace(context));
 181     return initialiser_ == NULL ? NULL : $ CYAssign(variable, initialiser_);
 182 }
 183
 184 CYExpression *CYDeclaration::ForEachIn(CYContext &context) {
 185     return $ CYVariable(identifier_);
 186 }
 187
 188 CYExpression *CYDeclaration::Replace(CYContext &context) {
 189     context.Replace(identifier_);
 190     context.scope_->Declare(context, identifier_, CYIdentifierVariable);
 191     return $ CYVariable(identifier_);
 192 }
 193
 194 CYProperty *CYDeclarations::Property(CYContext &context) { $T(NULL)
 195     return $ CYProperty(declaration_->identifier_, declaration_->initialiser_ ?: $U, next_->Property(context));
 196 }
 197
 198 CYCompound *CYDeclarations::Replace(CYContext &context) {
 199     CYCompound *compound;
 200     if (next_ == NULL) compound:
 201         compound = $ CYCompound();
 202     else {
 203         compound = next_->Replace(context);
 204         if (compound == NULL)
 205             goto compound;
 206     }
 207
 208     if (CYAssignment *assignment = declaration_->Assignment(context))
 209         compound->AddPrev(assignment);
 210     return compound;
 211 }
 212
 213 CYExpression *CYDirectMember::Replace(CYContext &context) {
 214     Replace_(context);
 215     return this;
 216 }
 217
 218 CYStatement *CYDoWhile::Replace(CYContext &context) {
 219     context.Replace(test_);
 220     context.Replace(code_);
 221     return this;
 222 }
 223
 224 void CYElement::Replace(CYContext &context) { $T()
 225     context.Replace(value_);
 226     next_->Replace(context);
 227 }
 228
 229 CYStatement *CYEmpty::Collapse(CYContext &context) {
 230     return next_;
 231 }
 232
 233 CYStatement *CYEmpty::Replace(CYContext &context) {
 234     return this;
 235 }
 236
 237 CYStatement *CYExpress::Collapse(CYContext &context) {
 238     if (CYExpress *express = dynamic_cast<CYExpress *>(next_)) {
 239         CYCompound *next(dynamic_cast<CYCompound *>(express->expression_));
 240         if (next == NULL)
 241             next = $ CYCompound(express->expression_);
 242         next->AddPrev(expression_);
 243         expression_ = next;
 244         SetNext(express->next_);
 245     }
 246
 247     return this;
 248 }
 249
 250 CYStatement *CYExpress::Replace(CYContext &context) {
 251     context.Replace(expression_);
 252     if (expression_ == NULL)
 253         return $ CYEmpty();
 254     return this;
 255 }
 256
 257 CYExpression *CYExpression::AddArgument(CYContext &context, CYExpression *value) {
 258     return $C1(this, value);
 259 }
 260
 261 CYExpression *CYExpression::ClassName(CYContext &context, bool object) {
 262     return this;
 263 }
 264
 265 CYExpression *CYExpression::ForEachIn(CYContext &context) {
 266     return this;
 267 }
 268
 269 CYExpression *CYExpression::ReplaceAll(CYContext &context) { $T(NULL)
 270     CYExpression *replace(this);
 271     context.Replace(replace);
 272
 273     if (CYExpression *next = next_->ReplaceAll(context))
 274         replace->SetNext(next);
 275     else
 276         replace->SetNext(next_);
 277
 278     return replace;
 279 }
 280
 281 CYNumber *CYFalse::Number(CYContext &context) {
 282     return $D(0);
 283 }
 284
 285 CYString *CYFalse::String(CYContext &context) {
 286     return $S("false");
 287 }
 288
 289 void CYFinally::Replace(CYContext &context) { $T()
 290     code_.Replace(context);
 291 }
 292
 293 CYStatement *CYFor::Replace(CYContext &context) {
 294     context.Replace(initialiser_);
 295     context.Replace(test_);
 296     context.Replace(increment_);
 297     context.Replace(code_);
 298     return this;
 299 }
 300
 301 CYStatement *CYForIn::Replace(CYContext &context) {
 302     // XXX: this actually might need a prefix statement
 303     context.Replace(initialiser_);
 304     context.Replace(set_);
 305     context.Replace(code_);
 306     return this;
 307 }
 308
 309 CYFunctionParameter *CYForInComprehension::Parameter(CYContext &context) const {
 310     return $ CYFunctionParameter(name_);
 311 }
 312
 313 CYStatement *CYForInComprehension::Replace(CYContext &context, CYStatement *statement) const {
 314     return $ CYForIn($ CYVariable(name_), set_, CYComprehension::Replace(context, statement));
 315 }
 316
 317 CYStatement *CYForEachIn::Replace(CYContext &context) {
 318     CYVariable *cys($V("$cys")), *cyt($V("$cyt"));
 319
 320     return $ CYLet($L2($L($I("$cys"), set_), $L($I("$cyt"))), $$->*
 321         $ CYForIn(cyt, cys, $ CYBlock($$->*
 322             $E($ CYAssign(initialiser_->ForEachIn(context), $M(cys, cyt)))->*
 323             code_
 324         ))
 325     );
 326 }
 327
 328 CYFunctionParameter *CYForEachInComprehension::Parameter(CYContext &context) const {
 329     return $ CYFunctionParameter(name_);
 330 }
 331
 332 CYStatement *CYForEachInComprehension::Replace(CYContext &context, CYStatement *statement) const {
 333     CYVariable *cys($V("$cys")), *name($ CYVariable(name_));
 334
 335     return $E($C0($F(NULL, $P1("$cys"), $$->*
 336         $E($ CYAssign(cys, set_))->*
 337         $ CYForIn(name, cys, $ CYBlock($$->*
 338             $E($ CYAssign(name, $M(cys, name)))->*
 339             CYComprehension::Replace(context, statement)
 340         ))
 341     )));
 342 }
 343
 344 void CYFunction::Inject(CYContext &context) {
 345     context.Replace(name_);
 346     context.scope_->Declare(context, name_, CYIdentifierOther);
 347 }
 348
 349 void CYFunction::Replace_(CYContext &context, bool outer) {
 350     if (outer)
 351         Inject(context);
 352
 353     CYScope scope;
 354     scope.parent_ = context.scope_;
 355     context.scope_ = &scope;
 356
 357     if (!outer && name_ != NULL)
 358         Inject(context);
 359
 360     if (parameters_ != NULL)
 361         parameters_ = parameters_->Replace(context, code_);
 362     code_.Replace(context);
 363
 364     context.scope_ = scope.parent_;
 365     scope.Scope(context, code_.statements_);
 366 }
 367
 368 CYExpression *CYFunctionExpression::Replace(CYContext &context) {
 369     Replace_(context, false);
 370     return this;
 371 }
 372
 373 CYFunctionParameter *CYFunctionParameter::Replace(CYContext &context, CYBlock &code) {
 374     name_ = name_->Replace(context);
 375     context.scope_->Declare(context, name_, CYIdentifierArgument);
 376     if (next_ != NULL)
 377         next_ = next_->Replace(context, code);
 378     return this;
 379 }
 380
 381 CYStatement *CYFunctionStatement::Replace(CYContext &context) {
 382     Replace_(context, true);
 383     return this;
 384 }
 385
 386 CYIdentifier *CYIdentifier::Replace(CYContext &context) {
 387     if (replace_ != NULL && replace_ != this)
 388         return replace_->Replace(context);
 389     replace_ = context.scope_->Lookup(context, this);
 390     return replace_;
 391 }
 392
 393 CYStatement *CYIf::Replace(CYContext &context) {
 394     context.Replace(test_);
 395     context.Replace(true_);
 396     context.Replace(false_);
 397     return this;
 398 }
 399
 400 CYFunctionParameter *CYIfComprehension::Parameter(CYContext &context) const {
 401     return NULL;
 402 }
 403
 404 CYStatement *CYIfComprehension::Replace(CYContext &context, CYStatement *statement) const {
 405     return $ CYIf(test_, CYComprehension::Replace(context, statement));
 406 }
 407
 408 CYExpression *CYIndirect::Replace(CYContext &context) {
 409     CYPrefix::Replace(context);
 410     return $M(rhs_, $S("$cyi"));
 411 }
 412
 413 CYExpression *CYIndirectMember::Replace(CYContext &context) {
 414     Replace_(context);
 415     return $M($ CYIndirect(object_), property_);
 416 }
 417
 418 CYExpression *CYInfix::Replace(CYContext &context) {
 419     context.Replace(lhs_);
 420     context.Replace(rhs_);
 421     return this;
 422 }
 423
 424 CYStatement *CYLabel::Replace(CYContext &context) {
 425     context.Replace(statement_);
 426     return this;
 427 }
 428
 429 CYStatement *CYLet::Replace(CYContext &context) {
 430     return $ CYWith($ CYObject(declarations_->Property(context)), &code_);
 431 }
 432
 433 void CYMember::Replace_(CYContext &context) {
 434     context.Replace(object_);
 435     context.Replace(property_);
 436 }
 437
 438 CYExpression *CYNew::AddArgument(CYContext &context, CYExpression *value) {
 439     CYArgument **argument(&arguments_);
 440     while (*argument != NULL)
 441         argument = &(*argument)->next_;
 442     *argument = $ CYArgument(value);
 443     return this;
 444 }
 445
 446 CYExpression *CYNew::Replace(CYContext &context) {
 447     context.Replace(constructor_);
 448     arguments_->Replace(context);
 449     return this;
 450 }
 451
 452 CYNumber *CYNull::Number(CYContext &context) {
 453     return $D(0);
 454 }
 455
 456 CYString *CYNull::String(CYContext &context) {
 457     return $S("null");
 458 }
 459
 460 CYNumber *CYNumber::Number(CYContext &context) {
 461     return this;
 462 }
 463
 464 CYString *CYNumber::String(CYContext &context) {
 465     // XXX: there is a precise algorithm for this
 466     return $S(apr_psprintf(context.pool_, "%.17g", Value()));
 467 }
 468
 469 CYExpression *CYObject::Replace(CYContext &context) {
 470     properties_->Replace(context);
 471     return this;
 472 }
 473
 474 CYFunctionParameter *CYOptionalFunctionParameter::Replace(CYContext &context, CYBlock &code) {
 475     CYFunctionParameter *parameter($ CYFunctionParameter(name_, next_));
 476     parameter = parameter->Replace(context, code);
 477
 478     CYVariable *name($ CYVariable(name_));
 479     code.AddPrev($ CYIf($ CYIdentical($ CYTypeOf(name), $S("undefined")), $$->*
 480         $E($ CYAssign(name, initializer_))
 481     ));
 482
 483     return parameter;
 484 }
 485
 486 CYExpression *CYPostfix::Replace(CYContext &context) {
 487     context.Replace(lhs_);
 488     return this;
 489 }
 490
 491 CYExpression *CYPrefix::Replace(CYContext &context) {
 492     context.Replace(rhs_);
 493     return this;
 494 }
 495
 496 // XXX: this is evil evil black magic. don't ask, don't tell... don't believe!
 497 #define MappingSet "0etnirsoalfucdphmgyvbxTwSNECAFjDLkMOIBPqzRH$_WXUVGYKQJZ"
 498 //#define MappingSet "0abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_"
 499
 500 namespace {
 501     struct IdentifierUsageLess :
 502         std::binary_function<CYIdentifier *, CYIdentifier *, bool>
 503     {
 504         _finline bool operator ()(CYIdentifier *lhs, CYIdentifier *rhs) const {
 505             if (lhs->usage_ != rhs->usage_)
 506                 return lhs->usage_ > rhs->usage_;
 507             return lhs < rhs;
 508         }
 509     };
 510
 511     typedef std::set<CYIdentifier *, IdentifierUsageLess> IdentifierUsages;
 512 }
 513
 514 void CYProgram::Replace(CYContext &context) {
 515     CYScope scope;
 516     scope.parent_ = context.scope_;
 517     context.scope_ = &scope;
 518     statements_ = statements_->ReplaceAll(context);
 519     context.scope_ = scope.parent_;
 520     scope.Scope(context, statements_);
 521
 522     size_t offset(0);
 523
 524     CYCStringSet external;
 525     for (CYIdentifierValueSet::const_iterator i(scope.identifiers_.begin()); i != scope.identifiers_.end(); ++i)
 526         external.insert((*i)->Word());
 527
 528     IdentifierUsages usages;
 529
 530     if (offset < context.rename_.size())
 531         for (CYIdentifier *i(context.rename_[offset].identifier_); i != NULL; i = i->next_)
 532              usages.insert(i);
 533
 534     // XXX: totalling the probable occurrences and sorting by them would improve the result
 535     for (CYIdentifierUsageVector::const_iterator i(context.rename_.begin()); i != context.rename_.end(); ++i, ++offset) {
 536         //std::cout << *i << ":" << (*i)->offset_ << std::endl;
 537
 538         const char *name;
 539
 540         if (context.options_.verbose_)
 541             name = apr_psprintf(context.pool_, "$%"APR_SIZE_T_FMT"", offset);
 542         else {
 543             char id[8];
 544             id[7] = '\0';
 545
 546           id:
 547             unsigned position(7), local(offset + 1);
 548
 549             do {
 550                 unsigned index(local % (sizeof(MappingSet) - 1));
 551                 local /= sizeof(MappingSet) - 1;
 552                 id[--position] = MappingSet[index];
 553             } while (local != 0);
 554
 555             if (external.find(id + position) != external.end()) {
 556                 ++offset;
 557                 goto id;
 558             }
 559
 560             name = apr_pstrmemdup(context.pool_, id + position, 7 - position);
 561             // XXX: at some point, this could become a keyword
 562         }
 563
 564         for (CYIdentifier *identifier(i->identifier_); identifier != NULL; identifier = identifier->next_)
 565             identifier->Set(name);
 566     }
 567 }
 568
 569 void CYProperty::Replace(CYContext &context) { $T()
 570     context.Replace(value_);
 571     next_->Replace(context);
 572 }
 573
 574 CYStatement *CYReturn::Replace(CYContext &context) {
 575     context.Replace(value_);
 576     return this;
 577 }
 578
 579 CYExpression *CYRubyBlock::Replace(CYContext &context) {
 580     // XXX: this needs to do something much more epic to handle return
 581     return call_->AddArgument(context, proc_->Replace(context));
 582 }
 583
 584 CYExpression *CYRubyProc::Replace(CYContext &context) {
 585     return $ CYFunctionExpression(NULL, parameters_, code_);
 586 }
 587
 588 void CYScope::Declare(CYContext &context, CYIdentifier *identifier, CYIdentifierFlags flags) {
 589     internal_.insert(CYIdentifierAddressFlagsMap::value_type(identifier, flags));
 590 }
 591
 592 CYIdentifier *CYScope::Lookup(CYContext &context, CYIdentifier *identifier) {
 593     std::pair<CYIdentifierValueSet::iterator, bool> insert(identifiers_.insert(identifier));
 594     return *insert.first;
 595 }
 596
 597 void CYScope::Merge(CYContext &context, CYIdentifier *identifier) {
 598     std::pair<CYIdentifierValueSet::iterator, bool> insert(identifiers_.insert(identifier));
 599     if (!insert.second) {
 600         if ((*insert.first)->offset_ < identifier->offset_)
 601             (*insert.first)->offset_ = identifier->offset_;
 602         identifier->replace_ = *insert.first;
 603         (*insert.first)->usage_ += identifier->usage_ + 1;
 604     }
 605 }
 606
 607 namespace {
 608     struct IdentifierOffset {
 609         size_t offset_;
 610         CYIdentifierFlags flags_;
 611         size_t usage_;
 612         CYIdentifier *identifier_;
 613
 614         IdentifierOffset(CYIdentifier *identifier, CYIdentifierFlags flags) :
 615             offset_(identifier->offset_),
 616             flags_(flags),
 617             usage_(identifier->usage_),
 618             identifier_(identifier)
 619         {
 620         }
 621     };
 622
 623     struct IdentifierOffsetLess :
 624         std::binary_function<const IdentifierOffset &, const IdentifierOffset &, bool>
 625     {
 626         _finline bool operator ()(const IdentifierOffset &lhs, const IdentifierOffset &rhs) const {
 627             if (lhs.offset_ != rhs.offset_)
 628                 return lhs.offset_ < rhs.offset_;
 629             if (lhs.flags_ != rhs.flags_)
 630                 return lhs.flags_ < rhs.flags_;
 631             /*if (lhs.usage_ != rhs.usage_)
 632                 return lhs.usage_ < rhs.usage_;*/
 633             return lhs.identifier_ < rhs.identifier_;
 634         }
 635     };
 636
 637     typedef std::set<IdentifierOffset, IdentifierOffsetLess> IdentifierOffsets;
 638 }
 639
 640 void CYScope::Scope(CYContext &context, CYStatement *&statements) {
 641     if (parent_ == NULL)
 642         return;
 643
 644     CYDeclarations *last(NULL), *curr(NULL);
 645
 646     IdentifierOffsets offsets;
 647
 648     for (CYIdentifierAddressFlagsMap::const_iterator i(internal_.begin()); i != internal_.end(); ++i)
 649         if (i->second != CYIdentifierMagic)
 650             offsets.insert(IdentifierOffset(i->first, i->second));
 651
 652     size_t offset(0);
 653
 654     for (IdentifierOffsets::const_iterator i(offsets.begin()); i != offsets.end(); ++i) {
 655         if (i->flags_ == CYIdentifierVariable) {
 656             CYDeclarations *next($ CYDeclarations($ CYDeclaration(i->identifier_)));
 657             if (last == NULL)
 658                 last = next;
 659             if (curr != NULL)
 660                 curr->SetNext(next);
 661             curr = next;
 662         }
 663
 664         if (offset < i->offset_)
 665             offset = i->offset_;
 666         if (context.rename_.size() <= offset)
 667             context.rename_.resize(offset + 1);
 668
 669         CYIdentifierUsage &rename(context.rename_[offset++]);
 670         i->identifier_->SetNext(rename.identifier_);
 671         rename.identifier_ = i->identifier_;
 672         rename.usage_ += i->identifier_->usage_ + 1;
 673     }
 674
 675     if (last != NULL) {
 676         CYVar *var($ CYVar(last));
 677         var->SetNext(statements);
 678         statements = var;
 679     }
 680
 681     for (CYIdentifierValueSet::const_iterator i(identifiers_.begin()); i != identifiers_.end(); ++i)
 682         if (internal_.find(*i) == internal_.end()) {
 683             //std::cout << *i << '=' << offset << std::endl;
 684             if ((*i)->offset_ < offset)
 685                 (*i)->offset_ = offset;
 686             parent_->Merge(context, *i);
 687         }
 688 }
 689
 690 CYStatement *CYStatement::Collapse(CYContext &context) {
 691     return this;
 692 }
 693
 694 CYStatement *CYStatement::ReplaceAll(CYContext &context) { $T(NULL)
 695     CYStatement *replace(this);
 696     context.Replace(replace);
 697     replace->SetNext(next_->ReplaceAll(context));
 698     return replace->Collapse(context);
 699 }
 700
 701 CYString *CYString::Concat(CYContext &context, CYString *rhs) const {
 702     size_t size(size_ + rhs->size_);
 703     char *value(new(context.pool_) char[size + 1]);
 704     memcpy(value, value_, size_);
 705     memcpy(value + size_, rhs->value_, rhs->size_);
 706     value[size] = '\0';
 707     return $S(value, size);
 708 }
 709
 710 CYNumber *CYString::Number(CYContext &context) {
 711     // XXX: there is a precise algorithm for this
 712     return NULL;
 713 }
 714
 715 CYString *CYString::String(CYContext &context) {
 716     return this;
 717 }
 718
 719 CYStatement *CYSwitch::Replace(CYContext &context) {
 720     context.Replace(value_);
 721     clauses_->Replace(context);
 722     return this;
 723 }
 724
 725 CYExpression *CYThis::Replace(CYContext &context) {
 726     return this;
 727 }
 728
 729 namespace cy {
 730 namespace Syntax {
 731
 732 CYStatement *Throw::Replace(CYContext &context) {
 733     context.Replace(value_);
 734     return this;
 735 }
 736
 737 } }
 738
 739 CYExpression *CYTrivial::Replace(CYContext &context) {
 740     return this;
 741 }
 742
 743 CYNumber *CYTrue::Number(CYContext &context) {
 744     return $D(1);
 745 }
 746
 747 CYString *CYTrue::String(CYContext &context) {
 748     return $S("true");
 749 }
 750
 751 namespace cy {
 752 namespace Syntax {
 753
 754 CYStatement *Try::Replace(CYContext &context) {
 755     code_.Replace(context);
 756     catch_->Replace(context);
 757     finally_->Replace(context);
 758     return this;
 759 }
 760
 761 } }
 762
 763 CYStatement *CYVar::Replace(CYContext &context) {
 764     return $E(declarations_->Replace(context));
 765 }
 766
 767 CYExpression *CYVariable::Replace(CYContext &context) {
 768     name_ = name_->Replace(context);
 769     return this;
 770 }
 771
 772 CYStatement *CYWhile::Replace(CYContext &context) {
 773     context.Replace(test_);
 774     context.Replace(code_);
 775     return this;
 776 }
 777
 778 CYStatement *CYWith::Replace(CYContext &context) {
 779     context.Replace(scope_);
 780     context.Replace(code_);
 781     return this;
 782 }
 783
 784 CYExpression *CYWord::ClassName(CYContext &context, bool object) {
 785     CYString *name($S(this));
 786     if (object)
 787         return $C1($V("objc_getClass"), name);
 788     else
 789         return name;
 790 }