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     CYScope scope(CYScopeCatch, context, code_.statements_);
 136
 137     context.Replace(name_);
 138     context.scope_->Declare(context, name_, CYIdentifierCatch);
 139
 140     code_.Replace(context);
 141     scope.Close();
 142 }
 143
 144 } }
 145
 146 void CYClause::Replace(CYContext &context) { $T()
 147     context.Replace(case_);
 148     statements_ = statements_->ReplaceAll(context);
 149     next_->Replace(context);
 150 }
 151
 152 CYStatement *CYComment::Replace(CYContext &context) {
 153     return this;
 154 }
 155
 156 CYExpression *CYCompound::Replace(CYContext &context) {
 157     expressions_ = expressions_->ReplaceAll(context);
 158     return expressions_ == NULL ? NULL : this;
 159 }
 160
 161 CYFunctionParameter *CYComprehension::Parameters(CYContext &context) const { $T(NULL)
 162     CYFunctionParameter *next(next_->Parameters(context));
 163     if (CYFunctionParameter *parameter = Parameter(context)) {
 164         parameter->SetNext(next);
 165         return parameter;
 166     } else
 167         return next;
 168 }
 169
 170 CYStatement *CYComprehension::Replace(CYContext &context, CYStatement *statement) const {
 171     return next_ == NULL ? statement : next_->Replace(context, statement);
 172 }
 173
 174 CYExpression *CYCondition::Replace(CYContext &context) {
 175     context.Replace(test_);
 176     context.Replace(true_);
 177     context.Replace(false_);
 178     return this;
 179 }
 180
 181 void CYContext::NonLocal(CYStatement *&statements) {
 182     CYContext &context(*this);
 183
 184     if (nextlocal_ != NULL && nextlocal_->identifier_ != NULL) {
 185         CYIdentifier *cye($I("$cye")->Replace(context));
 186         CYIdentifier *unique(nextlocal_->identifier_->Replace(context));
 187
 188         CYStatement *declare(
 189             $ CYVar($L1($L(unique, $ CYObject()))));
 190
 191         cy::Syntax::Catch *rescue(
 192             $ cy::Syntax::Catch(cye, $$->*
 193                 $ CYIf($ CYIdentical($M($ CYVariable(cye), $S("$cyk")), $ CYVariable(unique)), $$->*
 194                     $ CYReturn($M($ CYVariable(cye), $S("$cyv"))))->*
 195                 $ cy::Syntax::Throw($ CYVariable(cye))));
 196
 197         declare = declare->Replace(context);
 198         rescue->Replace(context);
 199
 200         statements = $$->*
 201             declare->*
 202             $ cy::Syntax::Try(statements, rescue, NULL);
 203     }
 204 }
 205
 206 CYIdentifier *CYContext::Unique() {
 207     CYContext &context(*this);
 208     return $ CYIdentifier(apr_psprintf(pool_, "$cy%u", unique_++));
 209 }
 210
 211 CYStatement *CYContinue::Replace(CYContext &context) {
 212     return this;
 213 }
 214
 215 CYAssignment *CYDeclaration::Assignment(CYContext &context) {
 216     CYExpression *variable(Replace(context));
 217     return initialiser_ == NULL ? NULL : $ CYAssign(variable, initialiser_);
 218 }
 219
 220 CYExpression *CYDeclaration::ForEachIn(CYContext &context) {
 221     return $ CYVariable(identifier_);
 222 }
 223
 224 CYExpression *CYDeclaration::Replace(CYContext &context) {
 225     context.Replace(identifier_);
 226     context.scope_->Declare(context, identifier_, CYIdentifierVariable);
 227     return $ CYVariable(identifier_);
 228 }
 229
 230 CYProperty *CYDeclarations::Property(CYContext &context) { $T(NULL)
 231     return $ CYProperty(declaration_->identifier_, declaration_->initialiser_ ?: $U, next_->Property(context));
 232 }
 233
 234 CYCompound *CYDeclarations::Replace(CYContext &context) {
 235     CYCompound *compound;
 236     if (next_ == NULL) compound:
 237         compound = $ CYCompound();
 238     else {
 239         compound = next_->Replace(context);
 240         if (compound == NULL)
 241             goto compound;
 242     }
 243
 244     if (CYAssignment *assignment = declaration_->Assignment(context))
 245         compound->AddPrev(assignment);
 246     return compound;
 247 }
 248
 249 CYExpression *CYDirectMember::Replace(CYContext &context) {
 250     Replace_(context);
 251     return this;
 252 }
 253
 254 CYStatement *CYDoWhile::Replace(CYContext &context) {
 255     context.Replace(test_);
 256     context.Replace(code_);
 257     return this;
 258 }
 259
 260 void CYElement::Replace(CYContext &context) { $T()
 261     context.Replace(value_);
 262     next_->Replace(context);
 263 }
 264
 265 CYStatement *CYEmpty::Collapse(CYContext &context) {
 266     return next_;
 267 }
 268
 269 CYStatement *CYEmpty::Replace(CYContext &context) {
 270     return this;
 271 }
 272
 273 CYStatement *CYExpress::Collapse(CYContext &context) {
 274     if (CYExpress *express = dynamic_cast<CYExpress *>(next_)) {
 275         CYCompound *next(dynamic_cast<CYCompound *>(express->expression_));
 276         if (next == NULL)
 277             next = $ CYCompound(express->expression_);
 278         next->AddPrev(expression_);
 279         expression_ = next;
 280         SetNext(express->next_);
 281     }
 282
 283     return this;
 284 }
 285
 286 CYStatement *CYExpress::Replace(CYContext &context) {
 287     context.Replace(expression_);
 288     if (expression_ == NULL)
 289         return $ CYEmpty();
 290     return this;
 291 }
 292
 293 CYExpression *CYExpression::AddArgument(CYContext &context, CYExpression *value) {
 294     return $C1(this, value);
 295 }
 296
 297 CYExpression *CYExpression::ClassName(CYContext &context, bool object) {
 298     return this;
 299 }
 300
 301 CYExpression *CYExpression::ForEachIn(CYContext &context) {
 302     return this;
 303 }
 304
 305 CYExpression *CYExpression::ReplaceAll(CYContext &context) { $T(NULL)
 306     CYExpression *replace(this);
 307     context.Replace(replace);
 308
 309     if (CYExpression *next = next_->ReplaceAll(context))
 310         replace->SetNext(next);
 311     else
 312         replace->SetNext(next_);
 313
 314     return replace;
 315 }
 316
 317 CYNumber *CYFalse::Number(CYContext &context) {
 318     return $D(0);
 319 }
 320
 321 CYString *CYFalse::String(CYContext &context) {
 322     return $S("false");
 323 }
 324
 325 void CYFinally::Replace(CYContext &context) { $T()
 326     code_.Replace(context);
 327 }
 328
 329 CYStatement *CYFor::Replace(CYContext &context) {
 330     context.Replace(initialiser_);
 331     context.Replace(test_);
 332     context.Replace(increment_);
 333     context.Replace(code_);
 334     return this;
 335 }
 336
 337 CYStatement *CYForIn::Replace(CYContext &context) {
 338     // XXX: this actually might need a prefix statement
 339     context.Replace(initialiser_);
 340     context.Replace(set_);
 341     context.Replace(code_);
 342     return this;
 343 }
 344
 345 CYFunctionParameter *CYForInComprehension::Parameter(CYContext &context) const {
 346     return $ CYFunctionParameter(name_);
 347 }
 348
 349 CYStatement *CYForInComprehension::Replace(CYContext &context, CYStatement *statement) const {
 350     return $ CYForIn($ CYVariable(name_), set_, CYComprehension::Replace(context, statement));
 351 }
 352
 353 CYStatement *CYForEachIn::Replace(CYContext &context) {
 354     CYVariable *cys($V("$cys")), *cyt($V("$cyt"));
 355
 356     return $ CYLet($L2($L($I("$cys"), set_), $L($I("$cyt"))), $$->*
 357         $ CYForIn(cyt, cys, $ CYBlock($$->*
 358             $E($ CYAssign(initialiser_->ForEachIn(context), $M(cys, cyt)))->*
 359             code_
 360         ))
 361     );
 362 }
 363
 364 CYFunctionParameter *CYForEachInComprehension::Parameter(CYContext &context) const {
 365     return $ CYFunctionParameter(name_);
 366 }
 367
 368 CYStatement *CYForEachInComprehension::Replace(CYContext &context, CYStatement *statement) const {
 369     CYVariable *cys($V("$cys")), *name($ CYVariable(name_));
 370
 371     return $E($C0($F(NULL, $P1("$cys"), $$->*
 372         $E($ CYAssign(cys, set_))->*
 373         $ CYForIn(name, cys, $ CYBlock($$->*
 374             $E($ CYAssign(name, $M(cys, name)))->*
 375             CYComprehension::Replace(context, statement)
 376         ))
 377     )));
 378 }
 379
 380 void CYFunction::Inject(CYContext &context) {
 381     context.Replace(name_);
 382     context.scope_->Declare(context, name_, CYIdentifierOther);
 383 }
 384
 385 void CYFunction::Replace_(CYContext &context, bool outer) {
 386     if (outer)
 387         Inject(context);
 388
 389     CYScope scope(CYScopeFunction, context, code_.statements_);
 390
 391     CYNonLocal *nonlocal(context.nonlocal_);
 392     CYNonLocal *nextlocal(context.nextlocal_);
 393
 394     bool localize;
 395     if (nonlocal_ != NULL) {
 396         localize = false;
 397         context.nonlocal_ = nonlocal_;
 398     } else {
 399         localize = true;
 400         nonlocal_ = $ CYNonLocal();
 401         context.nextlocal_ = nonlocal_;
 402     }
 403
 404     if (!outer && name_ != NULL)
 405         Inject(context);
 406
 407     if (parameters_ != NULL)
 408         parameters_ = parameters_->Replace(context, code_);
 409
 410     code_.Replace(context);
 411
 412     if (localize)
 413         context.NonLocal(code_.statements_);
 414
 415     context.nextlocal_ = nextlocal;
 416     context.nonlocal_ = nonlocal;
 417
 418     scope.Close();
 419 }
 420
 421 CYExpression *CYFunctionExpression::Replace(CYContext &context) {
 422     Replace_(context, false);
 423     return this;
 424 }
 425
 426 CYFunctionParameter *CYFunctionParameter::Replace(CYContext &context, CYBlock &code) {
 427     name_ = name_->Replace(context);
 428     context.scope_->Declare(context, name_, CYIdentifierArgument);
 429     if (next_ != NULL)
 430         next_ = next_->Replace(context, code);
 431     return this;
 432 }
 433
 434 CYStatement *CYFunctionStatement::Replace(CYContext &context) {
 435     Replace_(context, true);
 436     return this;
 437 }
 438
 439 CYIdentifier *CYIdentifier::Replace(CYContext &context) {
 440     if (replace_ != NULL && replace_ != this)
 441         return replace_->Replace(context);
 442     replace_ = context.scope_->Lookup(context, this);
 443     return replace_;
 444 }
 445
 446 CYStatement *CYIf::Replace(CYContext &context) {
 447     context.Replace(test_);
 448     context.Replace(true_);
 449     context.Replace(false_);
 450     return this;
 451 }
 452
 453 CYFunctionParameter *CYIfComprehension::Parameter(CYContext &context) const {
 454     return NULL;
 455 }
 456
 457 CYStatement *CYIfComprehension::Replace(CYContext &context, CYStatement *statement) const {
 458     return $ CYIf(test_, CYComprehension::Replace(context, statement));
 459 }
 460
 461 CYExpression *CYIndirect::Replace(CYContext &context) {
 462     CYPrefix::Replace(context);
 463     return $M(rhs_, $S("$cyi"));
 464 }
 465
 466 CYExpression *CYIndirectMember::Replace(CYContext &context) {
 467     Replace_(context);
 468     return $M($ CYIndirect(object_), property_);
 469 }
 470
 471 CYExpression *CYInfix::Replace(CYContext &context) {
 472     context.Replace(lhs_);
 473     context.Replace(rhs_);
 474     return this;
 475 }
 476
 477 CYStatement *CYLabel::Replace(CYContext &context) {
 478     context.Replace(statement_);
 479     return this;
 480 }
 481
 482 CYStatement *CYLet::Replace(CYContext &context) {
 483     return $ CYWith($ CYObject(declarations_->Property(context)), &code_);
 484 }
 485
 486 void CYMember::Replace_(CYContext &context) {
 487     context.Replace(object_);
 488     context.Replace(property_);
 489 }
 490
 491 CYExpression *CYNew::AddArgument(CYContext &context, CYExpression *value) {
 492     CYArgument **argument(&arguments_);
 493     while (*argument != NULL)
 494         argument = &(*argument)->next_;
 495     *argument = $ CYArgument(value);
 496     return this;
 497 }
 498
 499 CYExpression *CYNew::Replace(CYContext &context) {
 500     context.Replace(constructor_);
 501     arguments_->Replace(context);
 502     return this;
 503 }
 504
 505 CYNumber *CYNull::Number(CYContext &context) {
 506     return $D(0);
 507 }
 508
 509 CYString *CYNull::String(CYContext &context) {
 510     return $S("null");
 511 }
 512
 513 CYNumber *CYNumber::Number(CYContext &context) {
 514     return this;
 515 }
 516
 517 CYString *CYNumber::String(CYContext &context) {
 518     // XXX: there is a precise algorithm for this
 519     return $S(apr_psprintf(context.pool_, "%.17g", Value()));
 520 }
 521
 522 CYExpression *CYObject::Replace(CYContext &context) {
 523     properties_->Replace(context);
 524     return this;
 525 }
 526
 527 CYFunctionParameter *CYOptionalFunctionParameter::Replace(CYContext &context, CYBlock &code) {
 528     CYFunctionParameter *parameter($ CYFunctionParameter(name_, next_));
 529     parameter = parameter->Replace(context, code);
 530     initializer_ = initializer_->Replace(context);
 531
 532     CYVariable *name($ CYVariable(name_));
 533     code.AddPrev($ CYIf($ CYIdentical($ CYTypeOf(name), $S("undefined")), $$->*
 534         $E($ CYAssign(name, initializer_))
 535     ));
 536
 537     return parameter;
 538 }
 539
 540 CYExpression *CYPostfix::Replace(CYContext &context) {
 541     context.Replace(lhs_);
 542     return this;
 543 }
 544
 545 CYExpression *CYPrefix::Replace(CYContext &context) {
 546     context.Replace(rhs_);
 547     return this;
 548 }
 549
 550 // XXX: this is evil evil black magic. don't ask, don't tell... don't believe!
 551 #define MappingSet "0etnirsoalfucdphmgyvbxTwSNECAFjDLkMOIBPqzRH$_WXUVGYKQJZ"
 552 //#define MappingSet "0abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_"
 553
 554 namespace {
 555     struct IdentifierUsageLess :
 556         std::binary_function<CYIdentifier *, CYIdentifier *, bool>
 557     {
 558         _finline bool operator ()(CYIdentifier *lhs, CYIdentifier *rhs) const {
 559             if (lhs->usage_ != rhs->usage_)
 560                 return lhs->usage_ > rhs->usage_;
 561             return lhs < rhs;
 562         }
 563     };
 564
 565     typedef std::set<CYIdentifier *, IdentifierUsageLess> IdentifierUsages;
 566 }
 567
 568 void CYProgram::Replace(CYContext &context) {
 569     CYScope scope(CYScopeProgram, context, statements_);
 570
 571     context.nextlocal_ = $ CYNonLocal();
 572     statements_ = statements_->ReplaceAll(context);
 573     context.NonLocal(statements_);
 574
 575     scope.Close();
 576
 577     size_t offset(0);
 578
 579     CYCStringSet external;
 580     for (CYIdentifierValueSet::const_iterator i(scope.identifiers_.begin()); i != scope.identifiers_.end(); ++i)
 581         external.insert((*i)->Word());
 582
 583     IdentifierUsages usages;
 584
 585     if (offset < context.rename_.size())
 586         for (CYIdentifier *i(context.rename_[offset].identifier_); i != NULL; i = i->next_)
 587              usages.insert(i);
 588
 589     // XXX: totalling the probable occurrences and sorting by them would improve the result
 590     for (CYIdentifierUsageVector::const_iterator i(context.rename_.begin()); i != context.rename_.end(); ++i, ++offset) {
 591         //std::cout << *i << ":" << (*i)->offset_ << std::endl;
 592
 593         const char *name;
 594
 595         if (context.options_.verbose_)
 596             name = apr_psprintf(context.pool_, "$%"APR_SIZE_T_FMT"", offset);
 597         else {
 598             char id[8];
 599             id[7] = '\0';
 600
 601           id:
 602             unsigned position(7), local(offset + 1);
 603
 604             do {
 605                 unsigned index(local % (sizeof(MappingSet) - 1));
 606                 local /= sizeof(MappingSet) - 1;
 607                 id[--position] = MappingSet[index];
 608             } while (local != 0);
 609
 610             if (external.find(id + position) != external.end()) {
 611                 ++offset;
 612                 goto id;
 613             }
 614
 615             name = apr_pstrmemdup(context.pool_, id + position, 7 - position);
 616             // XXX: at some point, this could become a keyword
 617         }
 618
 619         for (CYIdentifier *identifier(i->identifier_); identifier != NULL; identifier = identifier->next_)
 620             identifier->Set(name);
 621     }
 622 }
 623
 624 void CYProperty::Replace(CYContext &context) { $T()
 625     context.Replace(value_);
 626     next_->Replace(context);
 627 }
 628
 629 CYStatement *CYReturn::Replace(CYContext &context) {
 630     if (context.nonlocal_ != NULL) {
 631         CYProperty *value(value_ == NULL ? NULL : $ CYProperty($S("$cyv"), value_));
 632         return $ cy::Syntax::Throw($ CYObject(
 633             $ CYProperty($S("$cyk"), $ CYVariable(context.nonlocal_->Target(context)), value)
 634         ));
 635     }
 636
 637     context.Replace(value_);
 638     return this;
 639 }
 640
 641 CYExpression *CYRubyBlock::Replace(CYContext &context) {
 642     // XXX: this needs to do something much more epic to handle return
 643     return call_->AddArgument(context, proc_->Replace(context));
 644 }
 645
 646 CYExpression *CYRubyProc::Replace(CYContext &context) {
 647     CYFunctionExpression *function($ CYFunctionExpression(NULL, parameters_, code_));
 648     function->nonlocal_ = context.nextlocal_;
 649     return function;
 650 }
 651
 652 CYScope::CYScope(CYScopeType type, CYContext &context, CYStatement *&statements) :
 653     type_(type),
 654     context_(context),
 655     statements_(statements),
 656     parent_(context.scope_)
 657 {
 658     context_.scope_ = this;
 659 }
 660
 661 void CYScope::Close() {
 662     context_.scope_ = parent_;
 663     Scope(context_, statements_);
 664 }
 665
 666 void CYScope::Declare(CYContext &context, CYIdentifier *identifier, CYIdentifierFlags flags) {
 667     if (type_ == CYScopeCatch && flags != CYIdentifierCatch)
 668         parent_->Declare(context, identifier, flags);
 669     else
 670         internal_.insert(CYIdentifierAddressFlagsMap::value_type(identifier, flags));
 671 }
 672
 673 CYIdentifier *CYScope::Lookup(CYContext &context, CYIdentifier *identifier) {
 674     std::pair<CYIdentifierValueSet::iterator, bool> insert(identifiers_.insert(identifier));
 675     return *insert.first;
 676 }
 677
 678 void CYScope::Merge(CYContext &context, CYIdentifier *identifier) {
 679     std::pair<CYIdentifierValueSet::iterator, bool> insert(identifiers_.insert(identifier));
 680     if (!insert.second) {
 681         if ((*insert.first)->offset_ < identifier->offset_)
 682             (*insert.first)->offset_ = identifier->offset_;
 683         identifier->replace_ = *insert.first;
 684         (*insert.first)->usage_ += identifier->usage_ + 1;
 685     }
 686 }
 687
 688 namespace {
 689     struct IdentifierOffset {
 690         size_t offset_;
 691         CYIdentifierFlags flags_;
 692         size_t usage_;
 693         CYIdentifier *identifier_;
 694
 695         IdentifierOffset(CYIdentifier *identifier, CYIdentifierFlags flags) :
 696             offset_(identifier->offset_),
 697             flags_(flags),
 698             usage_(identifier->usage_),
 699             identifier_(identifier)
 700         {
 701         }
 702     };
 703
 704     struct IdentifierOffsetLess :
 705         std::binary_function<const IdentifierOffset &, const IdentifierOffset &, bool>
 706     {
 707         _finline bool operator ()(const IdentifierOffset &lhs, const IdentifierOffset &rhs) const {
 708             if (lhs.offset_ != rhs.offset_)
 709                 return lhs.offset_ < rhs.offset_;
 710             if (lhs.flags_ != rhs.flags_)
 711                 return lhs.flags_ < rhs.flags_;
 712             /*if (lhs.usage_ != rhs.usage_)
 713                 return lhs.usage_ < rhs.usage_;*/
 714             return lhs.identifier_ < rhs.identifier_;
 715         }
 716     };
 717
 718     typedef std::set<IdentifierOffset, IdentifierOffsetLess> IdentifierOffsets;
 719 }
 720
 721 void CYScope::Scope(CYContext &context, CYStatement *&statements) {
 722     if (parent_ == NULL)
 723         return;
 724
 725     CYDeclarations *last(NULL), *curr(NULL);
 726
 727     IdentifierOffsets offsets;
 728
 729     for (CYIdentifierAddressFlagsMap::const_iterator i(internal_.begin()); i != internal_.end(); ++i)
 730         if (i->second != CYIdentifierMagic)
 731             offsets.insert(IdentifierOffset(i->first, i->second));
 732
 733     size_t offset(0);
 734
 735     for (IdentifierOffsets::const_iterator i(offsets.begin()); i != offsets.end(); ++i) {
 736         if (i->flags_ == CYIdentifierVariable) {
 737             CYDeclarations *next($ CYDeclarations($ CYDeclaration(i->identifier_)));
 738             if (last == NULL)
 739                 last = next;
 740             if (curr != NULL)
 741                 curr->SetNext(next);
 742             curr = next;
 743         }
 744
 745         if (offset < i->offset_)
 746             offset = i->offset_;
 747         if (context.rename_.size() <= offset)
 748             context.rename_.resize(offset + 1);
 749
 750         CYIdentifierUsage &rename(context.rename_[offset++]);
 751         i->identifier_->SetNext(rename.identifier_);
 752         rename.identifier_ = i->identifier_;
 753         rename.usage_ += i->identifier_->usage_ + 1;
 754     }
 755
 756     if (last != NULL) {
 757         CYVar *var($ CYVar(last));
 758         var->SetNext(statements);
 759         statements = var;
 760     }
 761
 762     for (CYIdentifierValueSet::const_iterator i(identifiers_.begin()); i != identifiers_.end(); ++i)
 763         if (internal_.find(*i) == internal_.end()) {
 764             //std::cout << *i << '=' << offset << std::endl;
 765             if ((*i)->offset_ < offset)
 766                 (*i)->offset_ = offset;
 767             parent_->Merge(context, *i);
 768         }
 769 }
 770
 771 CYStatement *CYStatement::Collapse(CYContext &context) {
 772     return this;
 773 }
 774
 775 CYStatement *CYStatement::ReplaceAll(CYContext &context) { $T(NULL)
 776     CYStatement *replace(this);
 777     context.Replace(replace);
 778     replace->SetNext(next_->ReplaceAll(context));
 779     return replace->Collapse(context);
 780 }
 781
 782 CYString *CYString::Concat(CYContext &context, CYString *rhs) const {
 783     size_t size(size_ + rhs->size_);
 784     char *value(new(context.pool_) char[size + 1]);
 785     memcpy(value, value_, size_);
 786     memcpy(value + size_, rhs->value_, rhs->size_);
 787     value[size] = '\0';
 788     return $S(value, size);
 789 }
 790
 791 CYNumber *CYString::Number(CYContext &context) {
 792     // XXX: there is a precise algorithm for this
 793     return NULL;
 794 }
 795
 796 CYString *CYString::String(CYContext &context) {
 797     return this;
 798 }
 799
 800 CYStatement *CYSwitch::Replace(CYContext &context) {
 801     context.Replace(value_);
 802     clauses_->Replace(context);
 803     return this;
 804 }
 805
 806 CYExpression *CYThis::Replace(CYContext &context) {
 807     return this;
 808 }
 809
 810 namespace cy {
 811 namespace Syntax {
 812
 813 CYStatement *Throw::Replace(CYContext &context) {
 814     context.Replace(value_);
 815     return this;
 816 }
 817
 818 } }
 819
 820 CYExpression *CYTrivial::Replace(CYContext &context) {
 821     return this;
 822 }
 823
 824 CYNumber *CYTrue::Number(CYContext &context) {
 825     return $D(1);
 826 }
 827
 828 CYString *CYTrue::String(CYContext &context) {
 829     return $S("true");
 830 }
 831
 832 namespace cy {
 833 namespace Syntax {
 834
 835 CYStatement *Try::Replace(CYContext &context) {
 836     code_.Replace(context);
 837     catch_->Replace(context);
 838     finally_->Replace(context);
 839     return this;
 840 }
 841
 842 } }
 843
 844 CYStatement *CYVar::Replace(CYContext &context) {
 845     return $E(declarations_->Replace(context));
 846 }
 847
 848 CYExpression *CYVariable::Replace(CYContext &context) {
 849     name_ = name_->Replace(context);
 850     return this;
 851 }
 852
 853 CYStatement *CYWhile::Replace(CYContext &context) {
 854     context.Replace(test_);
 855     context.Replace(code_);
 856     return this;
 857 }
 858
 859 CYStatement *CYWith::Replace(CYContext &context) {
 860     context.Replace(scope_);
 861     context.Replace(code_);
 862     return this;
 863 }
 864
 865 CYExpression *CYWord::ClassName(CYContext &context, bool object) {
 866     CYString *name($S(this));
 867     if (object)
 868         return $C1($V("objc_getClass"), name);
 869     else
 870         return name;
 871 }