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::Replace(CYContext &context) {
 118     context.Replace(function_);
 119     arguments_->Replace(context);
 120     return this;
 121 }
 122
 123 namespace cy {
 124 namespace Syntax {
 125
 126 void Catch::Replace(CYContext &context) { $T()
 127     code_.Replace(context);
 128 }
 129
 130 } }
 131
 132 void CYClause::Replace(CYContext &context) { $T()
 133     context.Replace(case_);
 134     statements_ = statements_->ReplaceAll(context);
 135     next_->Replace(context);
 136 }
 137
 138 CYStatement *CYComment::Replace(CYContext &context) {
 139     return this;
 140 }
 141
 142 CYExpression *CYCompound::Replace(CYContext &context) {
 143     expressions_ = expressions_->ReplaceAll(context);
 144     return expressions_ == NULL ? NULL : this;
 145 }
 146
 147 CYFunctionParameter *CYComprehension::Parameters(CYContext &context) const { $T(NULL)
 148     CYFunctionParameter *next(next_->Parameters(context));
 149     if (CYFunctionParameter *parameter = Parameter(context)) {
 150         parameter->SetNext(next);
 151         return parameter;
 152     } else
 153         return next;
 154 }
 155
 156 CYStatement *CYComprehension::Replace(CYContext &context, CYStatement *statement) const {
 157     return next_ == NULL ? statement : next_->Replace(context, statement);
 158 }
 159
 160 CYExpression *CYCondition::Replace(CYContext &context) {
 161     context.Replace(test_);
 162     context.Replace(true_);
 163     context.Replace(false_);
 164     return this;
 165 }
 166
 167 CYStatement *CYContinue::Replace(CYContext &context) {
 168     return this;
 169 }
 170
 171 CYAssignment *CYDeclaration::Assignment(CYContext &context) {
 172     CYExpression *variable(Replace(context));
 173     return initialiser_ == NULL ? NULL : $ CYAssign(variable, initialiser_);
 174 }
 175
 176 CYExpression *CYDeclaration::ForEachIn(CYContext &context) {
 177     return $ CYVariable(identifier_);
 178 }
 179
 180 CYExpression *CYDeclaration::Replace(CYContext &context) {
 181     context.Replace(identifier_);
 182     context.scope_->Declare(context, identifier_, CYIdentifierVariable);
 183     return $ CYVariable(identifier_);
 184 }
 185
 186 CYProperty *CYDeclarations::Property(CYContext &context) { $T(NULL)
 187     return $ CYProperty(declaration_->identifier_, declaration_->initialiser_ ?: $U, next_->Property(context));
 188 }
 189
 190 CYCompound *CYDeclarations::Replace(CYContext &context) {
 191     CYCompound *compound;
 192     if (next_ == NULL) compound:
 193         compound = $ CYCompound();
 194     else {
 195         compound = next_->Replace(context);
 196         if (compound == NULL)
 197             goto compound;
 198     }
 199
 200     if (CYAssignment *assignment = declaration_->Assignment(context))
 201         compound->AddPrev(assignment);
 202     return compound;
 203 }
 204
 205 CYExpression *CYDirectMember::Replace(CYContext &context) {
 206     Replace_(context);
 207     return this;
 208 }
 209
 210 CYStatement *CYDoWhile::Replace(CYContext &context) {
 211     context.Replace(test_);
 212     context.Replace(code_);
 213     return this;
 214 }
 215
 216 void CYElement::Replace(CYContext &context) { $T()
 217     context.Replace(value_);
 218     next_->Replace(context);
 219 }
 220
 221 CYStatement *CYEmpty::Collapse(CYContext &context) {
 222     return next_;
 223 }
 224
 225 CYStatement *CYEmpty::Replace(CYContext &context) {
 226     return this;
 227 }
 228
 229 CYStatement *CYExpress::Collapse(CYContext &context) {
 230     if (CYExpress *express = dynamic_cast<CYExpress *>(next_)) {
 231         CYCompound *next(dynamic_cast<CYCompound *>(express->expression_));
 232         if (next == NULL)
 233             next = $ CYCompound(express->expression_);
 234         next->AddPrev(expression_);
 235         expression_ = next;
 236         SetNext(express->next_);
 237     }
 238
 239     return this;
 240 }
 241
 242 CYStatement *CYExpress::Replace(CYContext &context) {
 243     context.Replace(expression_);
 244     if (expression_ == NULL)
 245         return $ CYEmpty();
 246     return this;
 247 }
 248
 249 CYExpression *CYExpression::ClassName(CYContext &context, bool object) {
 250     return this;
 251 }
 252
 253 CYExpression *CYExpression::ForEachIn(CYContext &context) {
 254     return this;
 255 }
 256
 257 CYExpression *CYExpression::ReplaceAll(CYContext &context) { $T(NULL)
 258     CYExpression *replace(this);
 259     context.Replace(replace);
 260
 261     if (CYExpression *next = next_->ReplaceAll(context))
 262         replace->SetNext(next);
 263     else
 264         replace->SetNext(next_);
 265
 266     return replace;
 267 }
 268
 269 CYNumber *CYFalse::Number(CYContext &context) {
 270     return $D(0);
 271 }
 272
 273 CYString *CYFalse::String(CYContext &context) {
 274     return $S("false");
 275 }
 276
 277 void CYFinally::Replace(CYContext &context) { $T()
 278     code_.Replace(context);
 279 }
 280
 281 CYStatement *CYFor::Replace(CYContext &context) {
 282     context.Replace(initialiser_);
 283     context.Replace(test_);
 284     context.Replace(increment_);
 285     context.Replace(code_);
 286     return this;
 287 }
 288
 289 CYStatement *CYForIn::Replace(CYContext &context) {
 290     // XXX: this actually might need a prefix statement
 291     context.Replace(initialiser_);
 292     context.Replace(set_);
 293     context.Replace(code_);
 294     return this;
 295 }
 296
 297 CYFunctionParameter *CYForInComprehension::Parameter(CYContext &context) const {
 298     return $ CYFunctionParameter(name_);
 299 }
 300
 301 CYStatement *CYForInComprehension::Replace(CYContext &context, CYStatement *statement) const {
 302     return $ CYForIn($ CYVariable(name_), set_, CYComprehension::Replace(context, statement));
 303 }
 304
 305 CYStatement *CYForEachIn::Replace(CYContext &context) {
 306     CYVariable *cys($V("$cys")), *cyt($V("$cyt"));
 307
 308     return $ CYLet($L2($L($I("$cys"), set_), $L($I("$cyt"))), $$->*
 309         $ CYForIn(cyt, cys, $ CYBlock($$->*
 310             $E($ CYAssign(initialiser_->ForEachIn(context), $M(cys, cyt)))->*
 311             code_
 312         ))
 313     );
 314 }
 315
 316 CYFunctionParameter *CYForEachInComprehension::Parameter(CYContext &context) const {
 317     return $ CYFunctionParameter(name_);
 318 }
 319
 320 CYStatement *CYForEachInComprehension::Replace(CYContext &context, CYStatement *statement) const {
 321     CYVariable *cys($V("$cys")), *name($ CYVariable(name_));
 322
 323     return $E($C0($F(NULL, $P1("$cys"), $$->*
 324         $E($ CYAssign(cys, set_))->*
 325         $ CYForIn(name, cys, $ CYBlock($$->*
 326             $E($ CYAssign(name, $M(cys, name)))->*
 327             CYComprehension::Replace(context, statement)
 328         ))
 329     )));
 330 }
 331
 332 void CYFunction::Inject(CYContext &context) {
 333     context.Replace(name_);
 334     context.scope_->Declare(context, name_, CYIdentifierOther);
 335 }
 336
 337 void CYFunction::Replace_(CYContext &context, bool outer) {
 338     if (outer)
 339         Inject(context);
 340
 341     parent_ = context.scope_;
 342     context.scope_ = this;
 343
 344     if (!outer && name_ != NULL)
 345         Inject(context);
 346
 347     parameters_->Replace(context);
 348     code_.Replace(context);
 349
 350     context.scope_ = parent_;
 351     Scope(context, code_.statements_);
 352 }
 353
 354 CYExpression *CYFunctionExpression::Replace(CYContext &context) {
 355     Replace_(context, false);
 356     return this;
 357 }
 358
 359 void CYFunctionParameter::Replace(CYContext &context) { $T()
 360     name_ = name_->Replace(context);
 361     context.scope_->Declare(context, name_, CYIdentifierArgument);
 362     next_->Replace(context);
 363 }
 364
 365 CYStatement *CYFunctionStatement::Replace(CYContext &context) {
 366     Replace_(context, true);
 367     return this;
 368 }
 369
 370 CYIdentifier *CYIdentifier::Replace(CYContext &context) {
 371     if (replace_ != NULL && replace_ != this)
 372         return replace_->Replace(context);
 373     replace_ = context.scope_->Lookup(context, this);
 374     return replace_;
 375 }
 376
 377 CYStatement *CYIf::Replace(CYContext &context) {
 378     context.Replace(test_);
 379     context.Replace(true_);
 380     context.Replace(false_);
 381     return this;
 382 }
 383
 384 CYFunctionParameter *CYIfComprehension::Parameter(CYContext &context) const {
 385     return NULL;
 386 }
 387
 388 CYStatement *CYIfComprehension::Replace(CYContext &context, CYStatement *statement) const {
 389     return $ CYIf(test_, CYComprehension::Replace(context, statement));
 390 }
 391
 392 CYExpression *CYIndirect::Replace(CYContext &context) {
 393     CYPrefix::Replace(context);
 394     return $M(rhs_, $S("$cyi"));
 395 }
 396
 397 CYExpression *CYIndirectMember::Replace(CYContext &context) {
 398     Replace_(context);
 399     return $M($ CYIndirect(object_), property_);
 400 }
 401
 402 CYExpression *CYInfix::Replace(CYContext &context) {
 403     context.Replace(lhs_);
 404     context.Replace(rhs_);
 405     return this;
 406 }
 407
 408 CYStatement *CYLabel::Replace(CYContext &context) {
 409     context.Replace(statement_);
 410     return this;
 411 }
 412
 413 CYStatement *CYLet::Replace(CYContext &context) {
 414     return $ CYWith($ CYObject(declarations_->Property(context)), &code_);
 415 }
 416
 417 void CYMember::Replace_(CYContext &context) {
 418     context.Replace(object_);
 419     context.Replace(property_);
 420 }
 421
 422 CYExpression *CYNew::Replace(CYContext &context) {
 423     context.Replace(constructor_);
 424     arguments_->Replace(context);
 425     return this;
 426 }
 427
 428 CYNumber *CYNull::Number(CYContext &context) {
 429     return $D(0);
 430 }
 431
 432 CYString *CYNull::String(CYContext &context) {
 433     return $S("null");
 434 }
 435
 436 CYNumber *CYNumber::Number(CYContext &context) {
 437     return this;
 438 }
 439
 440 CYString *CYNumber::String(CYContext &context) {
 441     // XXX: there is a precise algorithm for this
 442     return $S(apr_psprintf(context.pool_, "%.17g", Value()));
 443 }
 444
 445 CYExpression *CYObject::Replace(CYContext &context) {
 446     properties_->Replace(context);
 447     return this;
 448 }
 449
 450 CYExpression *CYPostfix::Replace(CYContext &context) {
 451     context.Replace(lhs_);
 452     return this;
 453 }
 454
 455 CYExpression *CYPrefix::Replace(CYContext &context) {
 456     context.Replace(rhs_);
 457     return this;
 458 }
 459
 460 // XXX: this is evil evil black magic. don't ask, don't tell... don't believe!
 461 #define MappingSet "0etnirsoalfucdphmgyvbxTwSNECAFjDLkMOIBPqzRH$_WXUVGYKQJZ"
 462 //#define MappingSet "0abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_"
 463
 464 void CYProgram::Replace(CYContext &context) {
 465     parent_ = context.scope_;
 466     CYProgram *program(context.program_);
 467
 468     context.scope_ = this;
 469     context.program_ = this;
 470
 471     statements_ = statements_->ReplaceAll(context);
 472
 473     context.scope_ = parent_;
 474     context.program_ = program;
 475     Scope(context, statements_);
 476
 477     size_t offset(0);
 478
 479     CYCStringSet external;
 480     for (CYIdentifierValueSet::const_iterator i(identifiers_.begin()); i != identifiers_.end(); ++i)
 481         external.insert((*i)->Word());
 482
 483     // XXX: totalling the probable occurrences and sorting by them would improve the result
 484     for (CYIdentifierAddressVector::const_iterator i(rename_.begin()); i != rename_.end(); ++i, ++offset) {
 485         //std::cout << *i << ":" << (*i)->offset_ << std::endl;
 486
 487         const char *name;
 488
 489         if (context.options_.verbose_)
 490             name = apr_psprintf(context.pool_, "$%"APR_SIZE_T_FMT"", offset);
 491         else {
 492             char id[8];
 493             id[7] = '\0';
 494
 495           id:
 496             unsigned position(7), local(offset + 1);
 497
 498             do {
 499                 unsigned index(local % (sizeof(MappingSet) - 1));
 500                 local /= sizeof(MappingSet) - 1;
 501                 id[--position] = MappingSet[index];
 502             } while (local != 0);
 503
 504             if (external.find(id + position) != external.end()) {
 505                 ++offset;
 506                 goto id;
 507             }
 508
 509             name = apr_pstrmemdup(context.pool_, id + position, 7 - position);
 510             // XXX: at some point, this could become a keyword
 511         }
 512
 513         for (CYIdentifier *identifier(*i); identifier != NULL; identifier = identifier->next_)
 514             identifier->Set(name);
 515     }
 516 }
 517
 518 void CYProperty::Replace(CYContext &context) { $T()
 519     context.Replace(value_);
 520     next_->Replace(context);
 521 }
 522
 523 CYStatement *CYReturn::Replace(CYContext &context) {
 524     context.Replace(value_);
 525     return this;
 526 }
 527
 528 void CYScope::Declare(CYContext &context, CYIdentifier *identifier, CYIdentifierFlags flags) {
 529     internal_.insert(CYIdentifierAddressFlagsMap::value_type(identifier, flags));
 530 }
 531
 532 CYIdentifier *CYScope::Lookup(CYContext &context, CYIdentifier *identifier) {
 533     std::pair<CYIdentifierValueSet::iterator, bool> insert(identifiers_.insert(identifier));
 534     return *insert.first;
 535 }
 536
 537 void CYScope::Merge(CYContext &context, CYIdentifier *identifier) {
 538     std::pair<CYIdentifierValueSet::iterator, bool> insert(identifiers_.insert(identifier));
 539     if (!insert.second) {
 540         if ((*insert.first)->offset_ < identifier->offset_)
 541             (*insert.first)->offset_ = identifier->offset_;
 542         identifier->replace_ = *insert.first;
 543     }
 544 }
 545
 546 namespace {
 547     struct IdentifierOffset {
 548         size_t offset_;
 549         CYIdentifierFlags flags_;
 550         CYIdentifier *identifier_;
 551
 552         IdentifierOffset(size_t offset, CYIdentifierFlags flags, CYIdentifier *identifier) :
 553             offset_(offset),
 554             flags_(flags),
 555             identifier_(identifier)
 556         {
 557         }
 558     };
 559
 560     struct IdentifierOffsetLess :
 561         std::binary_function<const IdentifierOffset &, const IdentifierOffset &, bool>
 562     {
 563         _finline bool operator ()(const IdentifierOffset &lhs, const IdentifierOffset &rhs) const {
 564             if (lhs.offset_ != rhs.offset_)
 565                 return lhs.offset_ < rhs.offset_;
 566             if (lhs.flags_ != rhs.flags_)
 567                 return lhs.flags_ < rhs.flags_;
 568             return lhs.identifier_ < rhs.identifier_;
 569         }
 570     };
 571
 572     typedef std::set<IdentifierOffset, IdentifierOffsetLess> IdentifierOffsets;
 573 }
 574
 575 void CYScope::Scope(CYContext &context, CYStatement *&statements) {
 576     CYDeclarations *last(NULL), *curr(NULL);
 577     CYProgram *program(context.program_);
 578
 579     IdentifierOffsets offsets;
 580
 581     // XXX: we don't want to do this in order, we want to sort it by probable occurrence
 582     for (CYIdentifierAddressFlagsMap::const_iterator i(internal_.begin()); i != internal_.end(); ++i)
 583         if (program != NULL && i->second != CYIdentifierMagic)
 584             offsets.insert(IdentifierOffset(i->first->offset_, i->second, i->first));
 585
 586     size_t offset(0);
 587
 588     for (IdentifierOffsets::const_iterator i(offsets.begin()); i != offsets.end(); ++i) {
 589         if (i->flags_ == CYIdentifierVariable) {
 590             CYDeclarations *next($ CYDeclarations($ CYDeclaration(i->identifier_)));
 591             if (last == NULL)
 592                 last = next;
 593             if (curr != NULL)
 594                 curr->SetNext(next);
 595             curr = next;
 596         }
 597
 598         if (offset < i->offset_)
 599             offset = i->offset_;
 600         if (program->rename_.size() <= offset)
 601             program->rename_.resize(offset + 1);
 602
 603         CYIdentifier *&identifier(program->rename_[offset++]);
 604         i->identifier_->SetNext(identifier);
 605         identifier = i->identifier_;
 606     }
 607
 608     if (last != NULL) {
 609         CYVar *var($ CYVar(last));
 610         var->SetNext(statements);
 611         statements = var;
 612     }
 613
 614     for (CYIdentifierValueSet::const_iterator i(identifiers_.begin()); i != identifiers_.end(); ++i)
 615         if (internal_.find(*i) == internal_.end()) {
 616             //std::cout << *i << '=' << offset << std::endl;
 617             if ((*i)->offset_ < offset)
 618                 (*i)->offset_ = offset;
 619             parent_->Merge(context, *i);
 620         }
 621 }
 622
 623 CYStatement *CYStatement::Collapse(CYContext &context) {
 624     return this;
 625 }
 626
 627 CYStatement *CYStatement::ReplaceAll(CYContext &context) { $T(NULL)
 628     CYStatement *replace(this);
 629     context.Replace(replace);
 630     replace->SetNext(next_->ReplaceAll(context));
 631     return replace->Collapse(context);
 632 }
 633
 634 CYString *CYString::Concat(CYContext &context, CYString *rhs) const {
 635     size_t size(size_ + rhs->size_);
 636     char *value(new(context.pool_) char[size + 1]);
 637     memcpy(value, value_, size_);
 638     memcpy(value + size_, rhs->value_, rhs->size_);
 639     value[size] = '\0';
 640     return $S(value, size);
 641 }
 642
 643 CYNumber *CYString::Number(CYContext &context) {
 644     // XXX: there is a precise algorithm for this
 645     return NULL;
 646 }
 647
 648 CYString *CYString::String(CYContext &context) {
 649     return this;
 650 }
 651
 652 CYStatement *CYSwitch::Replace(CYContext &context) {
 653     context.Replace(value_);
 654     clauses_->Replace(context);
 655     return this;
 656 }
 657
 658 CYExpression *CYThis::Replace(CYContext &context) {
 659     return this;
 660 }
 661
 662 namespace cy {
 663 namespace Syntax {
 664
 665 CYStatement *Throw::Replace(CYContext &context) {
 666     context.Replace(value_);
 667     return this;
 668 }
 669
 670 } }
 671
 672 CYExpression *CYTrivial::Replace(CYContext &context) {
 673     return this;
 674 }
 675
 676 CYNumber *CYTrue::Number(CYContext &context) {
 677     return $D(1);
 678 }
 679
 680 CYString *CYTrue::String(CYContext &context) {
 681     return $S("true");
 682 }
 683
 684 namespace cy {
 685 namespace Syntax {
 686
 687 CYStatement *Try::Replace(CYContext &context) {
 688     code_.Replace(context);
 689     catch_->Replace(context);
 690     finally_->Replace(context);
 691     return this;
 692 }
 693
 694 } }
 695
 696 CYStatement *CYVar::Replace(CYContext &context) {
 697     return $E(declarations_->Replace(context));
 698 }
 699
 700 CYExpression *CYVariable::Replace(CYContext &context) {
 701     name_ = name_->Replace(context);
 702     return this;
 703 }
 704
 705 CYStatement *CYWhile::Replace(CYContext &context) {
 706     context.Replace(test_);
 707     context.Replace(code_);
 708     return this;
 709 }
 710
 711 CYStatement *CYWith::Replace(CYContext &context) {
 712     context.Replace(scope_);
 713     context.Replace(code_);
 714     return this;
 715 }
 716
 717 CYExpression *CYWord::ClassName(CYContext &context, bool object) {
 718     CYString *name($S(this));
 719     if (object)
 720         return $C1($V("objc_getClass"), name);
 721     else
 722         return name;
 723 }