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