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($M($V(cye), $S("$cyk")), $V(unique)), $$->*
 194                     $ CYReturn($M($V(cye), $S("$cyv"))))->*
 195                 $ cy::Syntax::Throw($V(cye))));
 196
 197         context.Replace(declare);
 198         rescue->Replace(context);
 199
 200         statements = $$->*
 201             declare->*
 202             $ cy::Syntax::Try(statements, rescue, NULL);
 203     }
 204 }
 205
 206 CYIdentifier *CYContext::Unique() {
 207     return $ CYIdentifier(apr_psprintf($pool, "$cy%u", unique_++));
 208 }
 209
 210 CYStatement *CYContinue::Replace(CYContext &context) {
 211     return this;
 212 }
 213
 214 CYAssignment *CYDeclaration::Assignment(CYContext &context) {
 215     CYExpression *variable(Replace(context));
 216     return initialiser_ == NULL ? NULL : $ CYAssign(variable, initialiser_);
 217 }
 218
 219 CYExpression *CYDeclaration::ForEachIn(CYContext &context) {
 220     return $V(identifier_);
 221 }
 222
 223 CYExpression *CYDeclaration::Replace(CYContext &context) {
 224     context.Replace(identifier_);
 225     context.scope_->Declare(context, identifier_, CYIdentifierVariable);
 226     return $V(identifier_);
 227 }
 228
 229 CYProperty *CYDeclarations::Property(CYContext &context) { $T(NULL)
 230     return $ CYProperty(declaration_->identifier_, declaration_->initialiser_ ?: $U, next_->Property(context));
 231 }
 232
 233 CYCompound *CYDeclarations::Replace(CYContext &context) {
 234     CYCompound *compound;
 235     if (next_ == NULL) compound:
 236         compound = $ CYCompound();
 237     else {
 238         compound = next_->Replace(context);
 239         if (compound == NULL)
 240             goto compound;
 241     }
 242
 243     if (CYAssignment *assignment = declaration_->Assignment(context))
 244         compound->AddPrev(assignment);
 245     return compound;
 246 }
 247
 248 CYExpression *CYDirectMember::Replace(CYContext &context) {
 249     Replace_(context);
 250     return this;
 251 }
 252
 253 CYStatement *CYDoWhile::Replace(CYContext &context) {
 254     context.Replace(test_);
 255     context.Replace(code_);
 256     return this;
 257 }
 258
 259 void CYElement::Replace(CYContext &context) { $T()
 260     context.Replace(value_);
 261     next_->Replace(context);
 262 }
 263
 264 CYStatement *CYEmpty::Collapse(CYContext &context) {
 265     return next_;
 266 }
 267
 268 CYStatement *CYEmpty::Replace(CYContext &context) {
 269     return this;
 270 }
 271
 272 CYStatement *CYExpress::Collapse(CYContext &context) {
 273     if (CYExpress *express = dynamic_cast<CYExpress *>(next_)) {
 274         CYCompound *next(dynamic_cast<CYCompound *>(express->expression_));
 275         if (next == NULL)
 276             next = $ CYCompound(express->expression_);
 277         next->AddPrev(expression_);
 278         expression_ = next;
 279         SetNext(express->next_);
 280     }
 281
 282     return this;
 283 }
 284
 285 CYStatement *CYExpress::Replace(CYContext &context) {
 286     context.Replace(expression_);
 287     if (expression_ == NULL)
 288         return $ CYEmpty();
 289     return this;
 290 }
 291
 292 CYExpression *CYExpression::AddArgument(CYContext &context, CYExpression *value) {
 293     return $C1(this, value);
 294 }
 295
 296 CYExpression *CYExpression::ClassName(CYContext &context, bool object) {
 297     return this;
 298 }
 299
 300 CYExpression *CYExpression::ForEachIn(CYContext &context) {
 301     return this;
 302 }
 303
 304 CYExpression *CYExpression::ReplaceAll(CYContext &context) { $T(NULL)
 305     CYExpression *replace(this);
 306     context.Replace(replace);
 307
 308     if (CYExpression *next = next_->ReplaceAll(context))
 309         replace->SetNext(next);
 310     else
 311         replace->SetNext(next_);
 312
 313     return replace;
 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 CYStatement *CYForIn::Replace(CYContext &context) {
 337     // XXX: this actually might need a prefix statement
 338     context.Replace(initialiser_);
 339     context.Replace(set_);
 340     context.Replace(code_);
 341     return this;
 342 }
 343
 344 CYFunctionParameter *CYForInComprehension::Parameter(CYContext &context) const {
 345     return $ CYFunctionParameter(name_);
 346 }
 347
 348 CYStatement *CYForInComprehension::Replace(CYContext &context, CYStatement *statement) const {
 349     return $ CYForIn($V(name_), set_, CYComprehension::Replace(context, statement));
 350 }
 351
 352 CYStatement *CYForEachIn::Replace(CYContext &context) {
 353     CYIdentifier *cys($I("$cys")), *cyt($I("$cyt"));
 354
 355     return $ CYLet($L2($L(cys, set_), $L(cyt)), $$->*
 356         $ CYForIn($V(cyt), $V(cys), $ CYBlock($$->*
 357             $E($ CYAssign(initialiser_->ForEachIn(context), $M($V(cys), $V(cyt))))->*
 358             code_
 359         ))
 360     );
 361 }
 362
 363 CYFunctionParameter *CYForEachInComprehension::Parameter(CYContext &context) const {
 364     return $ CYFunctionParameter(name_);
 365 }
 366
 367 CYStatement *CYForEachInComprehension::Replace(CYContext &context, CYStatement *statement) const {
 368     CYIdentifier *cys($I("cys"));
 369
 370     return $E($C0($F(NULL, $P1("$cys"), $$->*
 371         $E($ CYAssign($V(cys), set_))->*
 372         $ CYForIn($V(name_), $V(cys), $ CYBlock($$->*
 373             $E($ CYAssign($V(name_), $M($V(cys), $V(name_))))->*
 374             CYComprehension::Replace(context, statement)
 375         ))
 376     )));
 377 }
 378
 379 void CYFunction::Inject(CYContext &context) {
 380     context.Replace(name_);
 381     context.scope_->Declare(context, name_, CYIdentifierOther);
 382 }
 383
 384 void CYFunction::Replace_(CYContext &context, bool outer) {
 385     if (outer)
 386         Inject(context);
 387
 388     CYScope scope(CYScopeFunction, context, code_.statements_);
 389
 390     CYNonLocal *nonlocal(context.nonlocal_);
 391     CYNonLocal *nextlocal(context.nextlocal_);
 392
 393     bool localize;
 394     if (nonlocal_ != NULL) {
 395         localize = false;
 396         context.nonlocal_ = nonlocal_;
 397     } else {
 398         localize = true;
 399         nonlocal_ = $ CYNonLocal();
 400         context.nextlocal_ = nonlocal_;
 401     }
 402
 403     if (!outer && name_ != NULL)
 404         Inject(context);
 405
 406     if (parameters_ != NULL)
 407         parameters_ = parameters_->Replace(context, code_);
 408
 409     code_.Replace(context);
 410
 411     if (localize)
 412         context.NonLocal(code_.statements_);
 413
 414     context.nextlocal_ = nextlocal;
 415     context.nonlocal_ = nonlocal;
 416
 417     scope.Close();
 418 }
 419
 420 CYExpression *CYFunctionExpression::Replace(CYContext &context) {
 421     Replace_(context, false);
 422     return this;
 423 }
 424
 425 CYFunctionParameter *CYFunctionParameter::Replace(CYContext &context, CYBlock &code) {
 426     context.Replace(name_);
 427     context.scope_->Declare(context, name_, CYIdentifierArgument);
 428     if (next_ != NULL)
 429         next_ = next_->Replace(context, code);
 430     return this;
 431 }
 432
 433 CYStatement *CYFunctionStatement::Replace(CYContext &context) {
 434     Replace_(context, true);
 435     return this;
 436 }
 437
 438 CYIdentifier *CYIdentifier::Replace(CYContext &context) {
 439     if (replace_ != NULL && replace_ != this)
 440         return replace_->Replace(context);
 441     replace_ = context.scope_->Lookup(context, this);
 442     return replace_;
 443 }
 444
 445 CYStatement *CYIf::Replace(CYContext &context) {
 446     context.Replace(test_);
 447     context.Replace(true_);
 448     context.Replace(false_);
 449     return this;
 450 }
 451
 452 CYFunctionParameter *CYIfComprehension::Parameter(CYContext &context) const {
 453     return NULL;
 454 }
 455
 456 CYStatement *CYIfComprehension::Replace(CYContext &context, CYStatement *statement) const {
 457     return $ CYIf(test_, CYComprehension::Replace(context, statement));
 458 }
 459
 460 CYExpression *CYIndirect::Replace(CYContext &context) {
 461     CYPrefix::Replace(context);
 462     return $M(rhs_, $S("$cyi"));
 463 }
 464
 465 CYExpression *CYIndirectMember::Replace(CYContext &context) {
 466     Replace_(context);
 467     return $M($ CYIndirect(object_), property_);
 468 }
 469
 470 CYExpression *CYInfix::Replace(CYContext &context) {
 471     context.Replace(lhs_);
 472     context.Replace(rhs_);
 473     return this;
 474 }
 475
 476 CYStatement *CYLabel::Replace(CYContext &context) {
 477     context.Replace(statement_);
 478     return this;
 479 }
 480
 481 CYStatement *CYLet::Replace(CYContext &context) {
 482     return $ CYWith($ CYObject(declarations_->Property(context)), &code_);
 483 }
 484
 485 void CYMember::Replace_(CYContext &context) {
 486     context.Replace(object_);
 487     context.Replace(property_);
 488 }
 489
 490 namespace cy {
 491 namespace Syntax {
 492
 493 CYExpression *New::AddArgument(CYContext &context, CYExpression *value) {
 494     CYArgument **argument(&arguments_);
 495     while (*argument != NULL)
 496         argument = &(*argument)->next_;
 497     *argument = $ CYArgument(value);
 498     return this;
 499 }
 500
 501 CYExpression *New::Replace(CYContext &context) {
 502     context.Replace(constructor_);
 503     arguments_->Replace(context);
 504     return this;
 505 }
 506
 507 } }
 508
 509 CYNumber *CYNull::Number(CYContext &context) {
 510     return $D(0);
 511 }
 512
 513 CYString *CYNull::String(CYContext &context) {
 514     return $S("null");
 515 }
 516
 517 CYNumber *CYNumber::Number(CYContext &context) {
 518     return this;
 519 }
 520
 521 CYString *CYNumber::String(CYContext &context) {
 522     // XXX: there is a precise algorithm for this
 523     return $S(apr_psprintf($pool, "%.17g", Value()));
 524 }
 525
 526 CYExpression *CYObject::Replace(CYContext &context) {
 527     properties_->Replace(context);
 528     return this;
 529 }
 530
 531 CYFunctionParameter *CYOptionalFunctionParameter::Replace(CYContext &context, CYBlock &code) {
 532     CYFunctionParameter *parameter($ CYFunctionParameter(name_, next_));
 533     parameter = parameter->Replace(context, code);
 534     context.Replace(initializer_);
 535
 536     CYVariable *name($V(name_));
 537     code.AddPrev($ CYIf($ CYIdentical($ CYTypeOf(name), $S("undefined")), $$->*
 538         $E($ CYAssign(name, initializer_))
 539     ));
 540
 541     return parameter;
 542 }
 543
 544 CYExpression *CYPostfix::Replace(CYContext &context) {
 545     context.Replace(lhs_);
 546     return this;
 547 }
 548
 549 CYExpression *CYPrefix::Replace(CYContext &context) {
 550     context.Replace(rhs_);
 551     return this;
 552 }
 553
 554 // XXX: this is evil evil black magic. don't ask, don't tell... don't believe!
 555 #define MappingSet "0etnirsoalfucdphmgyvbxTwSNECAFjDLkMOIBPqzRH$_WXUVGYKQJZ"
 556 //#define MappingSet "0abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_"
 557
 558 namespace {
 559     struct IdentifierUsageLess :
 560         std::binary_function<CYIdentifier *, CYIdentifier *, bool>
 561     {
 562         _finline bool operator ()(CYIdentifier *lhs, CYIdentifier *rhs) const {
 563             if (lhs->usage_ != rhs->usage_)
 564                 return lhs->usage_ > rhs->usage_;
 565             return lhs < rhs;
 566         }
 567     };
 568
 569     typedef std::set<CYIdentifier *, IdentifierUsageLess> IdentifierUsages;
 570 }
 571
 572 void CYProgram::Replace(CYContext &context) {
 573     CYScope scope(CYScopeProgram, context, statements_);
 574
 575     context.nextlocal_ = $ CYNonLocal();
 576     statements_ = statements_->ReplaceAll(context);
 577     context.NonLocal(statements_);
 578
 579     scope.Close();
 580
 581     size_t offset(0);
 582
 583     CYCStringSet external;
 584     for (CYIdentifierValueSet::const_iterator i(scope.identifiers_.begin()); i != scope.identifiers_.end(); ++i)
 585         external.insert((*i)->Word());
 586
 587     IdentifierUsages usages;
 588
 589     if (offset < context.rename_.size())
 590         for (CYIdentifier *i(context.rename_[offset].identifier_); i != NULL; i = i->next_)
 591              usages.insert(i);
 592
 593     // XXX: totalling the probable occurrences and sorting by them would improve the result
 594     for (CYIdentifierUsageVector::const_iterator i(context.rename_.begin()); i != context.rename_.end(); ++i, ++offset) {
 595         //std::cout << *i << ":" << (*i)->offset_ << std::endl;
 596
 597         const char *name;
 598
 599         if (context.options_.verbose_)
 600             name = apr_psprintf($pool, "$%"APR_SIZE_T_FMT"", offset);
 601         else {
 602             char id[8];
 603             id[7] = '\0';
 604
 605           id:
 606             unsigned position(7), local(offset + 1);
 607
 608             do {
 609                 unsigned index(local % (sizeof(MappingSet) - 1));
 610                 local /= sizeof(MappingSet) - 1;
 611                 id[--position] = MappingSet[index];
 612             } while (local != 0);
 613
 614             if (external.find(id + position) != external.end()) {
 615                 ++offset;
 616                 goto id;
 617             }
 618
 619             name = apr_pstrmemdup($pool, id + position, 7 - position);
 620             // XXX: at some point, this could become a keyword
 621         }
 622
 623         for (CYIdentifier *identifier(i->identifier_); identifier != NULL; identifier = identifier->next_)
 624             identifier->Set(name);
 625     }
 626 }
 627
 628 void CYProperty::Replace(CYContext &context) { $T()
 629     context.Replace(value_);
 630     next_->Replace(context);
 631 }
 632
 633 CYStatement *CYReturn::Replace(CYContext &context) {
 634     if (context.nonlocal_ != NULL) {
 635         CYProperty *value(value_ == NULL ? NULL : $ CYProperty($S("$cyv"), value_));
 636         return $ cy::Syntax::Throw($ CYObject(
 637             $ CYProperty($S("$cyk"), $V(context.nonlocal_->Target(context)), value)
 638         ));
 639     }
 640
 641     context.Replace(value_);
 642     return this;
 643 }
 644
 645 CYExpression *CYRubyBlock::Replace(CYContext &context) {
 646     // XXX: this needs to do something much more epic to handle return
 647     return call_->AddArgument(context, proc_->Replace(context));
 648 }
 649
 650 CYExpression *CYRubyProc::Replace(CYContext &context) {
 651     CYFunctionExpression *function($ CYFunctionExpression(NULL, parameters_, code_));
 652     function->nonlocal_ = context.nextlocal_;
 653     return function;
 654 }
 655
 656 CYScope::CYScope(CYScopeType type, CYContext &context, CYStatement *&statements) :
 657     type_(type),
 658     context_(context),
 659     statements_(statements),
 660     parent_(context.scope_)
 661 {
 662     context_.scope_ = this;
 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 (type_ == CYScopeCatch && flags != CYIdentifierCatch)
 672         parent_->Declare(context, identifier, flags);
 673     else
 674         internal_.insert(CYIdentifierAddressFlagsMap::value_type(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 CYStatement *CYStatement::Collapse(CYContext &context) {
 776     return this;
 777 }
 778
 779 CYStatement *CYStatement::ReplaceAll(CYContext &context) { $T(NULL)
 780     CYStatement *replace(this);
 781     context.Replace(replace);
 782     replace->SetNext(next_->ReplaceAll(context));
 783     return replace->Collapse(context);
 784 }
 785
 786 CYString *CYString::Concat(CYContext &context, CYString *rhs) const {
 787     size_t size(size_ + rhs->size_);
 788     char *value($ char[size + 1]);
 789     memcpy(value, value_, size_);
 790     memcpy(value + size_, rhs->value_, rhs->size_);
 791     value[size] = '\0';
 792     return $S(value, size);
 793 }
 794
 795 CYNumber *CYString::Number(CYContext &context) {
 796     // XXX: there is a precise algorithm for this
 797     return NULL;
 798 }
 799
 800 CYString *CYString::String(CYContext &context) {
 801     return this;
 802 }
 803
 804 CYStatement *CYSwitch::Replace(CYContext &context) {
 805     context.Replace(value_);
 806     clauses_->Replace(context);
 807     return this;
 808 }
 809
 810 CYExpression *CYThis::Replace(CYContext &context) {
 811     return this;
 812 }
 813
 814 namespace cy {
 815 namespace Syntax {
 816
 817 CYStatement *Throw::Replace(CYContext &context) {
 818     context.Replace(value_);
 819     return this;
 820 }
 821
 822 } }
 823
 824 CYExpression *CYTrivial::Replace(CYContext &context) {
 825     return this;
 826 }
 827
 828 CYNumber *CYTrue::Number(CYContext &context) {
 829     return $D(1);
 830 }
 831
 832 CYString *CYTrue::String(CYContext &context) {
 833     return $S("true");
 834 }
 835
 836 namespace cy {
 837 namespace Syntax {
 838
 839 CYStatement *Try::Replace(CYContext &context) {
 840     code_.Replace(context);
 841     catch_->Replace(context);
 842     finally_->Replace(context);
 843     return this;
 844 }
 845
 846 } }
 847
 848 CYStatement *CYVar::Replace(CYContext &context) {
 849     return $E(declarations_->Replace(context));
 850 }
 851
 852 CYExpression *CYVariable::Replace(CYContext &context) {
 853     context.Replace(name_);
 854     return this;
 855 }
 856
 857 CYStatement *CYWhile::Replace(CYContext &context) {
 858     context.Replace(test_);
 859     context.Replace(code_);
 860     return this;
 861 }
 862
 863 CYStatement *CYWith::Replace(CYContext &context) {
 864     context.Replace(scope_);
 865     context.Replace(code_);
 866     return this;
 867 }
 868
 869 CYExpression *CYWord::ClassName(CYContext &context, bool object) {
 870     CYString *name($S(this));
 871     if (object)
 872         return $C1($V("objc_getClass"), name);
 873     else
 874         return name;
 875 }