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