Replace.cpp

   1 /* Cycript - Optimizing JavaScript Compiler/Runtime
   2  * Copyright (C) 2009-2010  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 CYExpression *CYAdd::Replace(CYContext &context) {
  28     CYInfix::Replace(context);
  29
  30     CYExpression *lhp(lhs_->Primitive(context));
  31     CYExpression *rhp(rhs_->Primitive(context));
  32
  33     CYString *lhs(dynamic_cast<CYString *>(lhp));
  34     CYString *rhs(dynamic_cast<CYString *>(rhp));
  35
  36     if (lhs != NULL || rhs != NULL) {
  37         if (lhs == NULL) {
  38             lhs = lhp->String(context);
  39             if (lhs == NULL)
  40                 return this;
  41         } else if (rhs == NULL) {
  42             rhs = rhp->String(context);
  43             if (rhs == NULL)
  44                 return this;
  45         }
  46
  47         return lhs->Concat(context, rhs);
  48     }
  49
  50     if (CYNumber *lhn = lhp->Number(context))
  51         if (CYNumber *rhn = rhp->Number(context))
  52             return $D(lhn->Value() + rhn->Value());
  53
  54     return this;
  55 }
  56
  57 CYExpression *CYAddressOf::Replace(CYContext &context) {
  58     CYPrefix::Replace(context);
  59     return $C0($M(rhs_, $S("$cya")));
  60 }
  61
  62 void CYArgument::Replace(CYContext &context) { $T()
  63     context.Replace(value_);
  64     next_->Replace(context);
  65 }
  66
  67 CYExpression *CYArray::Replace(CYContext &context) {
  68     elements_->Replace(context);
  69     return this;
  70 }
  71
  72 CYExpression *CYArrayComprehension::Replace(CYContext &context) {
  73     CYVariable *cyv($V("$cyv"));
  74
  75     return $C0($F(NULL, $P1("$cyv", comprehensions_->Parameters(context)), $$->*
  76         $E($ CYAssign(cyv, $ CYArray()))->*
  77         comprehensions_->Replace(context, $E($C1($M(cyv, $S("push")), expression_)))->*
  78         $ CYReturn(cyv)
  79     ));
  80 }
  81
  82 CYExpression *CYAssignment::Replace(CYContext &context) {
  83     context.Replace(lhs_);
  84     context.Replace(rhs_);
  85     return this;
  86 }
  87
  88 CYStatement *CYBlock::Replace(CYContext &context) {
  89     context.ReplaceAll(statements_);
  90     if (statements_ == NULL)
  91         return $ CYEmpty();
  92     return this;
  93 }
  94
  95 CYStatement *CYBreak::Replace(CYContext &context) {
  96     return this;
  97 }
  98
  99 CYExpression *CYCall::AddArgument(CYContext &context, CYExpression *value) {
 100     CYArgument **argument(&arguments_);
 101     while (*argument != NULL)
 102         argument = &(*argument)->next_;
 103     *argument = $ CYArgument(value);
 104     return this;
 105 }
 106
 107 CYExpression *CYCall::Replace(CYContext &context) {
 108     context.Replace(function_);
 109     arguments_->Replace(context);
 110     return this;
 111 }
 112
 113 namespace cy {
 114 namespace Syntax {
 115
 116 void Catch::Replace(CYContext &context) { $T()
 117     CYScope scope(CYScopeCatch, context, code_.statements_);
 118
 119     context.Replace(name_);
 120     context.scope_->Declare(context, name_, CYIdentifierCatch);
 121
 122     code_.Replace(context);
 123     scope.Close();
 124 }
 125
 126 } }
 127
 128 void CYClause::Replace(CYContext &context) { $T()
 129     context.Replace(case_);
 130     context.ReplaceAll(statements_);
 131     next_->Replace(context);
 132 }
 133
 134 CYStatement *CYComment::Replace(CYContext &context) {
 135     return this;
 136 }
 137
 138 CYExpression *CYCompound::Replace(CYContext &context) {
 139     context.ReplaceAll(expressions_);
 140     return this;
 141 }
 142
 143 CYFunctionParameter *CYComprehension::Parameters(CYContext &context) const { $T(NULL)
 144     CYFunctionParameter *next(next_->Parameters(context));
 145     if (CYFunctionParameter *parameter = Parameter(context)) {
 146         parameter->SetNext(next);
 147         return parameter;
 148     } else
 149         return next;
 150 }
 151
 152 CYStatement *CYComprehension::Replace(CYContext &context, CYStatement *statement) const {
 153     return next_ == NULL ? statement : next_->Replace(context, statement);
 154 }
 155
 156 CYExpression *CYCondition::Replace(CYContext &context) {
 157     context.Replace(test_);
 158     context.Replace(true_);
 159     context.Replace(false_);
 160     return this;
 161 }
 162
 163 void CYContext::NonLocal(CYStatement *&statements) {
 164     CYContext &context(*this);
 165
 166     if (nextlocal_ != NULL && nextlocal_->identifier_ != NULL) {
 167         CYIdentifier *cye($I("$cye")->Replace(context));
 168         CYIdentifier *unique(nextlocal_->identifier_->Replace(context));
 169
 170         CYStatement *declare(
 171             $ CYVar($L1($L(unique, $ CYObject()))));
 172
 173         cy::Syntax::Catch *rescue(
 174             $ cy::Syntax::Catch(cye, $$->*
 175                 $ CYIf($ CYIdentical($M($V(cye), $S("$cyk")), $V(unique)), $$->*
 176                     $ CYReturn($M($V(cye), $S("$cyv"))))->*
 177                 $ cy::Syntax::Throw($V(cye))));
 178
 179         context.Replace(declare);
 180         rescue->Replace(context);
 181
 182         statements = $$->*
 183             declare->*
 184             $ cy::Syntax::Try(statements, rescue, NULL);
 185     }
 186 }
 187
 188 CYIdentifier *CYContext::Unique() {
 189     return $ CYIdentifier(apr_psprintf($pool, "$cy%u", unique_++));
 190 }
 191
 192 CYStatement *CYContinue::Replace(CYContext &context) {
 193     return this;
 194 }
 195
 196 CYAssignment *CYDeclaration::Assignment(CYContext &context) {
 197     CYExpression *variable(Replace(context));
 198     return initialiser_ == NULL ? NULL : $ CYAssign(variable, initialiser_);
 199 }
 200
 201 CYStatement *CYDeclaration::ForEachIn(CYContext &context, CYExpression *value) {
 202     return $ CYVar($L1($L(identifier_, value)));
 203 }
 204
 205 CYExpression *CYDeclaration::Replace(CYContext &context) {
 206     context.Replace(identifier_);
 207     context.scope_->Declare(context, identifier_, CYIdentifierVariable);
 208     return $V(identifier_);
 209 }
 210
 211 CYProperty *CYDeclarations::Property(CYContext &context) { $T(NULL)
 212     return $ CYProperty(declaration_->identifier_, declaration_->initialiser_ ?: $U, next_->Property(context));
 213 }
 214
 215 CYCompound *CYDeclarations::Replace(CYContext &context) {
 216     CYCompound *compound(next_ == NULL ? $ CYCompound() : next_->Replace(context));
 217     if (CYAssignment *assignment = declaration_->Assignment(context))
 218         compound->AddPrev(assignment);
 219     return compound;
 220 }
 221
 222 CYExpression *CYDirectMember::Replace(CYContext &context) {
 223     Replace_(context);
 224     return this;
 225 }
 226
 227 CYStatement *CYDoWhile::Replace(CYContext &context) {
 228     context.Replace(test_);
 229     context.Replace(code_);
 230     return this;
 231 }
 232
 233 void CYElement::Replace(CYContext &context) { $T()
 234     context.Replace(value_);
 235     next_->Replace(context);
 236 }
 237
 238 CYStatement *CYEmpty::Collapse(CYContext &context) {
 239     return next_;
 240 }
 241
 242 CYStatement *CYEmpty::Replace(CYContext &context) {
 243     return this;
 244 }
 245
 246 CYStatement *CYExpress::Collapse(CYContext &context) {
 247     if (CYExpress *express = dynamic_cast<CYExpress *>(next_)) {
 248         CYCompound *next(dynamic_cast<CYCompound *>(express->expression_));
 249         if (next == NULL)
 250             next = $ CYCompound(express->expression_);
 251         next->AddPrev(expression_);
 252         expression_ = next;
 253         SetNext(express->next_);
 254     }
 255
 256     return this;
 257 }
 258
 259 CYStatement *CYExpress::Replace(CYContext &context) {
 260     context.Replace(expression_);
 261     if (expression_ == NULL)
 262         return $ CYEmpty();
 263     return this;
 264 }
 265
 266 CYExpression *CYExpression::AddArgument(CYContext &context, CYExpression *value) {
 267     return $C1(this, value);
 268 }
 269
 270 CYExpression *CYExpression::ClassName(CYContext &context, bool object) {
 271     return this;
 272 }
 273
 274 CYStatement *CYExpression::ForEachIn(CYContext &context, CYExpression *value) {
 275     return $E($ CYAssign(this, value));
 276 }
 277
 278 CYNumber *CYFalse::Number(CYContext &context) {
 279     return $D(0);
 280 }
 281
 282 CYString *CYFalse::String(CYContext &context) {
 283     return $S("false");
 284 }
 285
 286 void CYFinally::Replace(CYContext &context) { $T()
 287     code_.Replace(context);
 288 }
 289
 290 CYStatement *CYFor::Replace(CYContext &context) {
 291     context.Replace(initialiser_);
 292     context.Replace(test_);
 293     context.Replace(increment_);
 294     context.Replace(code_);
 295     return this;
 296 }
 297
 298 CYStatement *CYForIn::Replace(CYContext &context) {
 299     // XXX: this actually might need a prefix statement
 300     context.Replace(initialiser_);
 301     context.Replace(set_);
 302     context.Replace(code_);
 303     return this;
 304 }
 305
 306 CYFunctionParameter *CYForInComprehension::Parameter(CYContext &context) const {
 307     return $ CYFunctionParameter(name_);
 308 }
 309
 310 CYStatement *CYForInComprehension::Replace(CYContext &context, CYStatement *statement) const {
 311     return $ CYForIn($V(name_), set_, CYComprehension::Replace(context, statement));
 312 }
 313
 314 CYStatement *CYForEachIn::Replace(CYContext &context) {
 315     CYIdentifier *cys($I("$cys")), *cyt($I("$cyt"));
 316
 317     return $ CYLet($L2($L(cys, set_), $L(cyt)), $$->*
 318         $ CYForIn($V(cyt), $V(cys), $ CYBlock($$->*
 319             initialiser_->ForEachIn(context, $M($V(cys), $V(cyt)))->*
 320             code_
 321         ))
 322     );
 323 }
 324
 325 CYFunctionParameter *CYForEachInComprehension::Parameter(CYContext &context) const {
 326     return $ CYFunctionParameter(name_);
 327 }
 328
 329 CYStatement *CYForEachInComprehension::Replace(CYContext &context, CYStatement *statement) const {
 330     CYIdentifier *cys($I("cys"));
 331
 332     return $E($C0($F(NULL, $P1("$cys"), $$->*
 333         $E($ CYAssign($V(cys), set_))->*
 334         $ CYForIn($V(name_), $V(cys), $ CYBlock($$->*
 335             $E($ CYAssign($V(name_), $M($V(cys), $V(name_))))->*
 336             CYComprehension::Replace(context, statement)
 337         ))
 338     )));
 339 }
 340
 341 void CYFunction::Inject(CYContext &context) {
 342     context.Replace(name_);
 343     context.scope_->Declare(context, name_, CYIdentifierOther);
 344 }
 345
 346 void CYFunction::Replace_(CYContext &context, bool outer) {
 347     if (outer)
 348         Inject(context);
 349
 350     CYScope scope(CYScopeFunction, context, code_.statements_);
 351
 352     CYNonLocal *nonlocal(context.nonlocal_);
 353     CYNonLocal *nextlocal(context.nextlocal_);
 354
 355     bool localize;
 356     if (nonlocal_ != NULL) {
 357         localize = false;
 358         context.nonlocal_ = nonlocal_;
 359     } else {
 360         localize = true;
 361         nonlocal_ = $ CYNonLocal();
 362         context.nextlocal_ = nonlocal_;
 363     }
 364
 365     if (!outer && name_ != NULL)
 366         Inject(context);
 367
 368     if (parameters_ != NULL)
 369         parameters_ = parameters_->Replace(context, code_);
 370
 371     code_.Replace(context);
 372
 373     if (localize)
 374         context.NonLocal(code_.statements_);
 375
 376     context.nextlocal_ = nextlocal;
 377     context.nonlocal_ = nonlocal;
 378
 379     scope.Close();
 380 }
 381
 382 CYExpression *CYFunctionExpression::Replace(CYContext &context) {
 383     Replace_(context, false);
 384     return this;
 385 }
 386
 387 CYFunctionParameter *CYFunctionParameter::Replace(CYContext &context, CYBlock &code) {
 388     context.Replace(name_);
 389     context.scope_->Declare(context, name_, CYIdentifierArgument);
 390     if (next_ != NULL)
 391         next_ = next_->Replace(context, code);
 392     return this;
 393 }
 394
 395 CYStatement *CYFunctionStatement::Replace(CYContext &context) {
 396     Replace_(context, true);
 397     return this;
 398 }
 399
 400 CYIdentifier *CYIdentifier::Replace(CYContext &context) {
 401     if (replace_ != NULL && replace_ != this)
 402         return replace_->Replace(context);
 403     replace_ = context.scope_->Lookup(context, this);
 404     return replace_;
 405 }
 406
 407 CYStatement *CYIf::Replace(CYContext &context) {
 408     context.Replace(test_);
 409     context.Replace(true_);
 410     context.Replace(false_);
 411     return this;
 412 }
 413
 414 CYFunctionParameter *CYIfComprehension::Parameter(CYContext &context) const {
 415     return NULL;
 416 }
 417
 418 CYStatement *CYIfComprehension::Replace(CYContext &context, CYStatement *statement) const {
 419     return $ CYIf(test_, CYComprehension::Replace(context, statement));
 420 }
 421
 422 CYExpression *CYIndirect::Replace(CYContext &context) {
 423     CYPrefix::Replace(context);
 424     return $M(rhs_, $S("$cyi"));
 425 }
 426
 427 CYExpression *CYIndirectMember::Replace(CYContext &context) {
 428     Replace_(context);
 429     return $M($ CYIndirect(object_), property_);
 430 }
 431
 432 CYExpression *CYInfix::Replace(CYContext &context) {
 433     context.Replace(lhs_);
 434     context.Replace(rhs_);
 435     return this;
 436 }
 437
 438 CYStatement *CYLabel::Replace(CYContext &context) {
 439     context.Replace(statement_);
 440     return this;
 441 }
 442
 443 CYStatement *CYLet::Replace(CYContext &context) {
 444     return $ CYWith($ CYObject(declarations_->Property(context)), &code_);
 445 }
 446
 447 void CYMember::Replace_(CYContext &context) {
 448     context.Replace(object_);
 449     context.Replace(property_);
 450 }
 451
 452 namespace cy {
 453 namespace Syntax {
 454
 455 CYExpression *New::AddArgument(CYContext &context, CYExpression *value) {
 456     CYSetLast(arguments_, $ CYArgument(value));
 457     return this;
 458 }
 459
 460 CYExpression *New::Replace(CYContext &context) {
 461     context.Replace(constructor_);
 462     arguments_->Replace(context);
 463     return this;
 464 }
 465
 466 } }
 467
 468 CYNumber *CYNull::Number(CYContext &context) {
 469     return $D(0);
 470 }
 471
 472 CYString *CYNull::String(CYContext &context) {
 473     return $S("null");
 474 }
 475
 476 CYNumber *CYNumber::Number(CYContext &context) {
 477     return this;
 478 }
 479
 480 CYString *CYNumber::String(CYContext &context) {
 481     // XXX: there is a precise algorithm for this
 482     return $S(apr_psprintf($pool, "%.17g", Value()));
 483 }
 484
 485 CYExpression *CYObject::Replace(CYContext &context) {
 486     properties_->Replace(context);
 487     return this;
 488 }
 489
 490 CYFunctionParameter *CYOptionalFunctionParameter::Replace(CYContext &context, CYBlock &code) {
 491     CYFunctionParameter *parameter($ CYFunctionParameter(name_, next_));
 492     parameter = parameter->Replace(context, code);
 493     context.Replace(initializer_);
 494
 495     CYVariable *name($V(name_));
 496     code.AddPrev($ CYIf($ CYIdentical($ CYTypeOf(name), $S("undefined")), $$->*
 497         $E($ CYAssign(name, initializer_))
 498     ));
 499
 500     return parameter;
 501 }
 502
 503 CYExpression *CYPostfix::Replace(CYContext &context) {
 504     context.Replace(lhs_);
 505     return this;
 506 }
 507
 508 CYExpression *CYPrefix::Replace(CYContext &context) {
 509     context.Replace(rhs_);
 510     return this;
 511 }
 512
 513 // XXX: this is evil evil black magic. don't ask, don't tell... don't believe!
 514 #define MappingSet "0etnirsoalfucdphmgyvbxTwSNECAFjDLkMOIBPqzRH$_WXUVGYKQJZ"
 515 //#define MappingSet "0abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_"
 516
 517 namespace {
 518     struct IdentifierUsageLess :
 519         std::binary_function<CYIdentifier *, CYIdentifier *, bool>
 520     {
 521         _finline bool operator ()(CYIdentifier *lhs, CYIdentifier *rhs) const {
 522             if (lhs->usage_ != rhs->usage_)
 523                 return lhs->usage_ > rhs->usage_;
 524             return lhs < rhs;
 525         }
 526     };
 527
 528     typedef std::set<CYIdentifier *, IdentifierUsageLess> IdentifierUsages;
 529 }
 530
 531 void CYProgram::Replace(CYContext &context) {
 532     CYScope scope(CYScopeProgram, context, statements_);
 533
 534     context.nextlocal_ = $ CYNonLocal();
 535     context.ReplaceAll(statements_);
 536     context.NonLocal(statements_);
 537
 538     scope.Close();
 539
 540     size_t offset(0);
 541
 542     CYCStringSet external;
 543     for (CYIdentifierValueSet::const_iterator i(scope.identifiers_.begin()); i != scope.identifiers_.end(); ++i)
 544         external.insert((*i)->Word());
 545
 546     IdentifierUsages usages;
 547
 548     if (offset < context.rename_.size())
 549         CYForEach (i, context.rename_[offset].identifier_)
 550             usages.insert(i);
 551
 552     // XXX: totalling the probable occurrences and sorting by them would improve the result
 553     for (CYIdentifierUsageVector::const_iterator i(context.rename_.begin()); i != context.rename_.end(); ++i, ++offset) {
 554         //std::cout << *i << ":" << (*i)->offset_ << std::endl;
 555
 556         const char *name;
 557
 558         if (context.options_.verbose_)
 559             name = apr_psprintf($pool, "$%"APR_SIZE_T_FMT"", offset);
 560         else {
 561             char id[8];
 562             id[7] = '\0';
 563
 564           id:
 565             unsigned position(7), local(offset + 1);
 566
 567             do {
 568                 unsigned index(local % (sizeof(MappingSet) - 1));
 569                 local /= sizeof(MappingSet) - 1;
 570                 id[--position] = MappingSet[index];
 571             } while (local != 0);
 572
 573             if (external.find(id + position) != external.end()) {
 574                 ++offset;
 575                 goto id;
 576             }
 577
 578             name = apr_pstrmemdup($pool, id + position, 7 - position);
 579             // XXX: at some point, this could become a keyword
 580         }
 581
 582         CYForEach (identifier, i->identifier_)
 583             identifier->Set(name);
 584     }
 585 }
 586
 587 void CYProperty::Replace(CYContext &context) { $T()
 588     context.Replace(value_);
 589     next_->Replace(context);
 590 }
 591
 592 CYStatement *CYReturn::Replace(CYContext &context) {
 593     if (context.nonlocal_ != NULL) {
 594         CYProperty *value(value_ == NULL ? NULL : $ CYProperty($S("$cyv"), value_));
 595         return $ cy::Syntax::Throw($ CYObject(
 596             $ CYProperty($S("$cyk"), $V(context.nonlocal_->Target(context)), value)
 597         ));
 598     }
 599
 600     context.Replace(value_);
 601     return this;
 602 }
 603
 604 CYExpression *CYRubyBlock::Replace(CYContext &context) {
 605     // XXX: this needs to do something much more epic to handle return
 606     return call_->AddArgument(context, proc_->Replace(context));
 607 }
 608
 609 CYExpression *CYRubyProc::Replace(CYContext &context) {
 610     CYFunctionExpression *function($ CYFunctionExpression(NULL, parameters_, code_));
 611     function->nonlocal_ = context.nextlocal_;
 612     return function;
 613 }
 614
 615 CYScope::CYScope(CYScopeType type, CYContext &context, CYStatement *&statements) :
 616     type_(type),
 617     context_(context),
 618     statements_(statements),
 619     parent_(context.scope_)
 620 {
 621     context_.scope_ = this;
 622 }
 623
 624 CYScope::~CYScope() {
 625 }
 626
 627 void CYScope::Close() {
 628     context_.scope_ = parent_;
 629     Scope(context_, statements_);
 630 }
 631
 632 void CYScope::Declare(CYContext &context, CYIdentifier *identifier, CYIdentifierFlags flags) {
 633     if (type_ == CYScopeCatch && flags != CYIdentifierCatch)
 634         parent_->Declare(context, identifier, flags);
 635     else
 636         internal_.insert(CYIdentifierAddressFlagsMap::value_type(identifier, flags));
 637 }
 638
 639 CYIdentifier *CYScope::Lookup(CYContext &context, CYIdentifier *identifier) {
 640     std::pair<CYIdentifierValueSet::iterator, bool> insert(identifiers_.insert(identifier));
 641     return *insert.first;
 642 }
 643
 644 void CYScope::Merge(CYContext &context, CYIdentifier *identifier) {
 645     std::pair<CYIdentifierValueSet::iterator, bool> insert(identifiers_.insert(identifier));
 646     if (!insert.second) {
 647         if ((*insert.first)->offset_ < identifier->offset_)
 648             (*insert.first)->offset_ = identifier->offset_;
 649         identifier->replace_ = *insert.first;
 650         (*insert.first)->usage_ += identifier->usage_ + 1;
 651     }
 652 }
 653
 654 namespace {
 655     struct IdentifierOffset {
 656         size_t offset_;
 657         CYIdentifierFlags flags_;
 658         size_t usage_;
 659         CYIdentifier *identifier_;
 660
 661         IdentifierOffset(CYIdentifier *identifier, CYIdentifierFlags flags) :
 662             offset_(identifier->offset_),
 663             flags_(flags),
 664             usage_(identifier->usage_),
 665             identifier_(identifier)
 666         {
 667         }
 668     };
 669
 670     struct IdentifierOffsetLess :
 671         std::binary_function<const IdentifierOffset &, const IdentifierOffset &, bool>
 672     {
 673         _finline bool operator ()(const IdentifierOffset &lhs, const IdentifierOffset &rhs) const {
 674             if (lhs.offset_ != rhs.offset_)
 675                 return lhs.offset_ < rhs.offset_;
 676             if (lhs.flags_ != rhs.flags_)
 677                 return lhs.flags_ < rhs.flags_;
 678             /*if (lhs.usage_ != rhs.usage_)
 679                 return lhs.usage_ < rhs.usage_;*/
 680             return lhs.identifier_ < rhs.identifier_;
 681         }
 682     };
 683
 684     typedef std::set<IdentifierOffset, IdentifierOffsetLess> IdentifierOffsets;
 685 }
 686
 687 void CYScope::Scope(CYContext &context, CYStatement *&statements) {
 688     if (parent_ == NULL)
 689         return;
 690
 691     CYDeclarations *last(NULL), *curr(NULL);
 692
 693     IdentifierOffsets offsets;
 694
 695     for (CYIdentifierAddressFlagsMap::const_iterator i(internal_.begin()); i != internal_.end(); ++i)
 696         if (i->second != CYIdentifierMagic)
 697             offsets.insert(IdentifierOffset(i->first, i->second));
 698
 699     size_t offset(0);
 700
 701     for (IdentifierOffsets::const_iterator i(offsets.begin()); i != offsets.end(); ++i) {
 702         if (i->flags_ == CYIdentifierVariable) {
 703             CYDeclarations *next($ CYDeclarations($ CYDeclaration(i->identifier_)));
 704             if (last == NULL)
 705                 last = next;
 706             if (curr != NULL)
 707                 curr->SetNext(next);
 708             curr = next;
 709         }
 710
 711         if (offset < i->offset_)
 712             offset = i->offset_;
 713         if (context.rename_.size() <= offset)
 714             context.rename_.resize(offset + 1);
 715
 716         CYIdentifierUsage &rename(context.rename_[offset++]);
 717         i->identifier_->SetNext(rename.identifier_);
 718         rename.identifier_ = i->identifier_;
 719         rename.usage_ += i->identifier_->usage_ + 1;
 720     }
 721
 722     if (last != NULL) {
 723         CYVar *var($ CYVar(last));
 724         var->SetNext(statements);
 725         statements = var;
 726     }
 727
 728     for (CYIdentifierValueSet::const_iterator i(identifiers_.begin()); i != identifiers_.end(); ++i)
 729         if (internal_.find(*i) == internal_.end()) {
 730             //std::cout << *i << '=' << offset << std::endl;
 731             if ((*i)->offset_ < offset)
 732                 (*i)->offset_ = offset;
 733             parent_->Merge(context, *i);
 734         }
 735 }
 736
 737 CYStatement *CYStatement::Collapse(CYContext &context) {
 738     return this;
 739 }
 740
 741 CYString *CYString::Concat(CYContext &context, CYString *rhs) const {
 742     size_t size(size_ + rhs->size_);
 743     char *value($ char[size + 1]);
 744     memcpy(value, value_, size_);
 745     memcpy(value + size_, rhs->value_, rhs->size_);
 746     value[size] = '\0';
 747     return $S(value, size);
 748 }
 749
 750 CYNumber *CYString::Number(CYContext &context) {
 751     // XXX: there is a precise algorithm for this
 752     return NULL;
 753 }
 754
 755 CYString *CYString::String(CYContext &context) {
 756     return this;
 757 }
 758
 759 CYStatement *CYSwitch::Replace(CYContext &context) {
 760     context.Replace(value_);
 761     clauses_->Replace(context);
 762     return this;
 763 }
 764
 765 CYExpression *CYThis::Replace(CYContext &context) {
 766     return this;
 767 }
 768
 769 namespace cy {
 770 namespace Syntax {
 771
 772 CYStatement *Throw::Replace(CYContext &context) {
 773     context.Replace(value_);
 774     return this;
 775 }
 776
 777 } }
 778
 779 CYExpression *CYTrivial::Replace(CYContext &context) {
 780     return this;
 781 }
 782
 783 CYNumber *CYTrue::Number(CYContext &context) {
 784     return $D(1);
 785 }
 786
 787 CYString *CYTrue::String(CYContext &context) {
 788     return $S("true");
 789 }
 790
 791 namespace cy {
 792 namespace Syntax {
 793
 794 CYStatement *Try::Replace(CYContext &context) {
 795     code_.Replace(context);
 796     catch_->Replace(context);
 797     finally_->Replace(context);
 798     return this;
 799 }
 800
 801 } }
 802
 803 CYStatement *CYVar::Replace(CYContext &context) {
 804     return $E(declarations_->Replace(context));
 805 }
 806
 807 CYExpression *CYVariable::Replace(CYContext &context) {
 808     context.Replace(name_);
 809     return this;
 810 }
 811
 812 CYStatement *CYWhile::Replace(CYContext &context) {
 813     context.Replace(test_);
 814     context.Replace(code_);
 815     return this;
 816 }
 817
 818 CYStatement *CYWith::Replace(CYContext &context) {
 819     context.Replace(scope_);
 820     context.Replace(code_);
 821     return this;
 822 }
 823
 824 CYExpression *CYWord::ClassName(CYContext &context, bool object) {
 825     CYString *name($S(this));
 826     if (object)
 827         return $C1($V("objc_getClass"), name);
 828     else
 829         return name;
 830 }