text: /*
   * Copyright (C) 2010-2019 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
   * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
   * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
   * THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #pragma once
  
  #include "Lexer.h"
  #include "ParserFunctionInfo.h"
  #include "YarrSyntaxChecker.h"
  
  namespace JSC {
  
  class SyntaxChecker {
  public:
      struct BinaryExprContext {
          BinaryExprContext(SyntaxChecker& context)
              : m_context(&context)
          {
              m_token = m_context->m_topBinaryExpr;
              m_context->m_topBinaryExpr = 0;
          }
          ~BinaryExprContext()
          {
              m_context->m_topBinaryExpr = m_token;
          }
      private:
          int m_token;
          SyntaxChecker* m_context;
      };
      struct UnaryExprContext {
          UnaryExprContext(SyntaxChecker& context)
              : m_context(&context)
          {
              m_token = m_context->m_topUnaryToken;
              m_context->m_topUnaryToken = 0;
          }
          ~UnaryExprContext()
          {
              m_context->m_topUnaryToken = m_token;
          }
      private:
          int m_token;
          SyntaxChecker* m_context;
      };
      
      SyntaxChecker(VM& , void*)
      {
      }
  
      static const constexpr int MetaPropertyBit = 0x80000000;
      enum : int { NoneExpr = 0,
          ResolveEvalExpr, ResolveExpr, IntegerExpr, DoubleExpr, StringExpr, BigIntExpr,
          ThisExpr, NullExpr, BoolExpr, RegExpExpr, ObjectLiteralExpr,
          FunctionExpr, ClassExpr, SuperExpr, ImportExpr, BracketExpr, DotExpr, CallExpr,
          NewExpr, PreExpr, PostExpr, UnaryExpr, BinaryExpr, OptionalChain,
          ConditionalExpr, AssignmentExpr, TypeofExpr,
          DeleteExpr, ArrayLiteralExpr, BindingDestructuring, RestParameter,
          ArrayDestructuring, ObjectDestructuring, SourceElementsResult,
          FunctionBodyResult, SpreadExpr, ObjectSpreadExpr, ArgumentsResult,
          PropertyListResult, ArgumentsListResult, ElementsListResult,
          StatementResult, FormalParameterListResult, ClauseResult,
          ClauseListResult, CommaExpr, DestructuringAssignment,
          TemplateStringResult, TemplateStringListResult,
          TemplateExpressionListResult, TemplateExpr,
          TaggedTemplateExpr, YieldExpr, AwaitExpr,
          ModuleNameResult,
          ImportSpecifierResult, ImportSpecifierListResult,
          ExportSpecifierResult, ExportSpecifierListResult,
  
          NewTargetExpr = MetaPropertyBit | 0,
          ImportMetaExpr = MetaPropertyBit | 1,
      };
      typedef int ExpressionType;
  
      typedef ExpressionType Expression;
      typedef int SourceElements;
      typedef int Arguments;
      typedef ExpressionType Comma;
      struct Property {
          ALWAYS_INLINE Property(void* = 0)
              : type((PropertyNode::Type)0)
          {
          }
          ALWAYS_INLINE Property(const Identifier* ident, PropertyNode::Type ty)
              : name(ident)
              , type(ty)
          {
          }
          ALWAYS_INLINE Property(PropertyNode::Type ty)
              : name(0)
              , type(ty)
          {
          }
          ALWAYS_INLINE bool operator!() { return !type; }
          const Identifier* name;
          PropertyNode::Type type;
      };
      typedef int PropertyList;
      typedef int ElementList;
      typedef int ArgumentsList;
      typedef int TemplateExpressionList;
      typedef int TemplateString;
      typedef int TemplateStringList;
      typedef int TemplateLiteral;
      typedef int FormalParameterList;
      typedef int FunctionBody;
      typedef int ClassExpression;
      typedef int ModuleName;
      typedef int ImportSpecifier;
      typedef int ImportSpecifierList;
      typedef int ExportSpecifier;
      typedef int ExportSpecifierList;
      typedef int Statement;
      typedef int ClauseList;
      typedef int Clause;
      typedef int BinaryOperand;
      typedef int DestructuringPattern;
      typedef DestructuringPattern ArrayPattern;
      typedef DestructuringPattern ObjectPattern;
      typedef DestructuringPattern RestPattern;
  
      static const bool CreatesAST = false;
      static const bool NeedsFreeVariableInfo = false;
      static const bool CanUseFunctionCache = true;
      static const unsigned DontBuildKeywords = LexexFlagsDontBuildKeywords;
      static const unsigned DontBuildStrings = LexerFlagsDontBuildStrings;
  
      int createSourceElements() { return SourceElementsResult; }
      ExpressionType makeFunctionCallNode(const JSTokenLocation&, ExpressionType, bool, int, int, int, int, size_t, bool) { return CallExpr; }
      ExpressionType createCommaExpr(const JSTokenLocation&, ExpressionType expr) { return expr; }
      ExpressionType appendToCommaExpr(const JSTokenLocation&, ExpressionType& head, ExpressionType, ExpressionType next) { head = next; return next; }
      ExpressionType makeAssignNode(const JSTokenLocation&, ExpressionType, Operator, ExpressionType, bool, bool, int, int, int) { return AssignmentExpr; }
      ExpressionType makePrefixNode(const JSTokenLocation&, ExpressionType, Operator, int, int, int) { return PreExpr; }
      ExpressionType makePostfixNode(const JSTokenLocation&, ExpressionType, Operator, int, int, int) { return PostExpr; }
      ExpressionType makeTypeOfNode(const JSTokenLocation&, ExpressionType) { return TypeofExpr; }
      ExpressionType makeDeleteNode(const JSTokenLocation&, ExpressionType, int, int, int) { return DeleteExpr; }
      ExpressionType makeNegateNode(const JSTokenLocation&, ExpressionType) { return UnaryExpr; }
      ExpressionType makeBitwiseNotNode(const JSTokenLocation&, ExpressionType) { return UnaryExpr; }
      ExpressionType createLogicalNot(const JSTokenLocation&, ExpressionType) { return UnaryExpr; }
      ExpressionType createUnaryPlus(const JSTokenLocation&, ExpressionType) { return UnaryExpr; }
      ExpressionType createVoid(const JSTokenLocation&, ExpressionType) { return UnaryExpr; }
      ExpressionType createImportExpr(const JSTokenLocation&, ExpressionType, int, int, int) { return ImportExpr; }
      ExpressionType createThisExpr(const JSTokenLocation&) { return ThisExpr; }
      ExpressionType createSuperExpr(const JSTokenLocation&) { return SuperExpr; }
      ExpressionType createNewTargetExpr(const JSTokenLocation&) { return NewTargetExpr; }
      ExpressionType createImportMetaExpr(const JSTokenLocation&, ExpressionType) { return ImportMetaExpr; }
      ALWAYS_INLINE bool isMetaProperty(ExpressionType type) { return type & MetaPropertyBit; }
      ALWAYS_INLINE bool isNewTarget(ExpressionType type) { return type == NewTargetExpr; }
      ALWAYS_INLINE bool isImportMeta(ExpressionType type) { return type == ImportMetaExpr; }
      ExpressionType createResolve(const JSTokenLocation&, const Identifier&, int, int) { return ResolveExpr; }
      ExpressionType createObjectLiteral(const JSTokenLocation&) { return ObjectLiteralExpr; }
      ExpressionType createObjectLiteral(const JSTokenLocation&, int) { return ObjectLiteralExpr; }
      ExpressionType createArray(const JSTokenLocation&, int) { return ArrayLiteralExpr; }
      ExpressionType createArray(const JSTokenLocation&, int, int) { return ArrayLiteralExpr; }
      ExpressionType createDoubleExpr(const JSTokenLocation&, double) { return DoubleExpr; }
      ExpressionType createIntegerExpr(const JSTokenLocation&, double) { return IntegerExpr; }
      ExpressionType createBigInt(const JSTokenLocation&, const Identifier*, int) { return BigIntExpr; }
      ExpressionType createString(const JSTokenLocation&, const Identifier*) { return StringExpr; }
      ExpressionType createBoolean(const JSTokenLocation&, bool) { return BoolExpr; }
      ExpressionType createNull(const JSTokenLocation&) { return NullExpr; }
      ExpressionType createBracketAccess(const JSTokenLocation&, ExpressionType, ExpressionType, bool, int, int, int) { return BracketExpr; }
      ExpressionType createDotAccess(const JSTokenLocation&, ExpressionType, const Identifier*, int, int, int) { return DotExpr; }
      ExpressionType createRegExp(const JSTokenLocation&, const Identifier& pattern, const Identifier& flags, int) { return Yarr::hasError(Yarr::checkSyntax(pattern.string(), flags.string())) ? 0 : RegExpExpr; }
      ExpressionType createNewExpr(const JSTokenLocation&, ExpressionType, int, int, int, int) { return NewExpr; }
      ExpressionType createNewExpr(const JSTokenLocation&, ExpressionType, int, int) { return NewExpr; }
      ExpressionType createOptionalChain(const JSTokenLocation&, ExpressionType, ExpressionType, bool) { return OptionalChain; }
      ExpressionType createConditionalExpr(const JSTokenLocation&, ExpressionType, ExpressionType, ExpressionType) { return ConditionalExpr; }
      ExpressionType createAssignResolve(const JSTokenLocation&, const Identifier&, ExpressionType, int, int, int, AssignmentContext) { return AssignmentExpr; }
      ExpressionType createEmptyVarExpression(const JSTokenLocation&, const Identifier&) { return AssignmentExpr; }
      ExpressionType createEmptyLetExpression(const JSTokenLocation&, const Identifier&) { return AssignmentExpr; }
      ExpressionType createYield(const JSTokenLocation&) { return YieldExpr; }
      ExpressionType createYield(const JSTokenLocation&, ExpressionType, bool, int, int, int) { return YieldExpr; }
      ExpressionType createAwait(const JSTokenLocation&, ExpressionType, int, int, int) { return AwaitExpr; }
      ClassExpression createClassExpr(const JSTokenLocation&, const ParserClassInfo<SyntaxChecker>&, VariableEnvironment&, ExpressionType, ExpressionType, PropertyList) { return ClassExpr; }
      ExpressionType createFunctionExpr(const JSTokenLocation&, const ParserFunctionInfo<SyntaxChecker>&) { return FunctionExpr; }
      ExpressionType createGeneratorFunctionBody(const JSTokenLocation&, const ParserFunctionInfo<SyntaxChecker>&, const Identifier&) { return FunctionExpr; }
      ExpressionType createAsyncFunctionBody(const JSTokenLocation&, const ParserFunctionInfo<SyntaxChecker>&) { return FunctionExpr; }
      int createFunctionMetadata(const JSTokenLocation&, const JSTokenLocation&, int, int, bool, int, int, int, ConstructorKind, SuperBinding, unsigned, SourceParseMode, bool, InnerArrowFunctionCodeFeatures = NoInnerArrowFunctionFeatures) { return FunctionBodyResult; }
      ExpressionType createArrowFunctionExpr(const JSTokenLocation&, const ParserFunctionInfo<SyntaxChecker>&) { return FunctionExpr; }
      ExpressionType createMethodDefinition(const JSTokenLocation&, const ParserFunctionInfo<SyntaxChecker>&) { return FunctionExpr; }
      void setFunctionNameStart(int, int) { }
      int createArguments() { return ArgumentsResult; }
      int createArguments(int) { return ArgumentsResult; }
      ExpressionType createSpreadExpression(const JSTokenLocation&, ExpressionType, int, int, int) { return SpreadExpr; }
      ExpressionType createObjectSpreadExpression(const JSTokenLocation&, ExpressionType, int, int, int) { return ObjectSpreadExpr; }
      TemplateString createTemplateString(const JSTokenLocation&, const Identifier*, const Identifier*) { return TemplateStringResult; }
      TemplateStringList createTemplateStringList(TemplateString) { return TemplateStringListResult; }
      TemplateStringList createTemplateStringList(TemplateStringList, TemplateString) { return TemplateStringListResult; }
      TemplateExpressionList createTemplateExpressionList(Expression) { return TemplateExpressionListResult; }
      TemplateExpressionList createTemplateExpressionList(TemplateExpressionList, Expression) { return TemplateExpressionListResult; }
      TemplateLiteral createTemplateLiteral(const JSTokenLocation&, TemplateStringList) { return TemplateExpr; }
      TemplateLiteral createTemplateLiteral(const JSTokenLocation&, TemplateStringList, TemplateExpressionList) { return TemplateExpr; }
      ExpressionType createTaggedTemplate(const JSTokenLocation&, ExpressionType, TemplateLiteral, int, int, int) { return TaggedTemplateExpr; }
  
      int createArgumentsList(const JSTokenLocation&, int) { return ArgumentsListResult; }
      int createArgumentsList(const JSTokenLocation&, int, int) { return ArgumentsListResult; }
      Property createProperty(const Identifier* name, int, PropertyNode::Type type, PropertyNode::PutType, bool complete, SuperBinding, InferName, ClassElementTag)
      {
          if (!complete)
              return Property(type);
          ASSERT(name);
          return Property(name, type);
      }
      Property createProperty(int, PropertyNode::Type type, PropertyNode::PutType, bool, SuperBinding, ClassElementTag)
      {
          return Property(type);
      }
      Property createProperty(VM& vm, ParserArena& parserArena, double name, int, PropertyNode::Type type, PropertyNode::PutType, bool complete, SuperBinding, ClassElementTag)
      {
          if (!complete)
              return Property(type);
          return Property(&parserArena.identifierArena().makeNumericIdentifier(vm, name), type);
      }
      Property createProperty(int, int, PropertyNode::Type type, PropertyNode::PutType, bool, SuperBinding, ClassElementTag)
      {
          return Property(type);
      }
      int createPropertyList(const JSTokenLocation&, Property) { return PropertyListResult; }
      int createPropertyList(const JSTokenLocation&, Property, int) { return PropertyListResult; }
      int createElementList(int, int) { return ElementsListResult; }
      int createElementList(int, int, int) { return ElementsListResult; }
      int createElementList(int) { return ElementsListResult; }
      int createFormalParameterList() { return FormalParameterListResult; }
      void appendParameter(int, DestructuringPattern, int) { }
      int createClause(int, int) { return ClauseResult; }
      int createClauseList(int) { return ClauseListResult; }
      int createClauseList(int, int) { return ClauseListResult; }
      int createFuncDeclStatement(const JSTokenLocation&, const ParserFunctionInfo<SyntaxChecker>&) { return StatementResult; }
      int createClassDeclStatement(const JSTokenLocation&, ClassExpression,
          const JSTextPosition&, const JSTextPosition&, int, int) { return StatementResult; }
      int createBlockStatement(const JSTokenLocation&, int, int, int, VariableEnvironment&, DeclarationStacks::FunctionStack&&) { return StatementResult; }
      int createExprStatement(const JSTokenLocation&, int, int, int) { return StatementResult; }
      int createIfStatement(const JSTokenLocation&, int, int, int, int) { return StatementResult; }
      int createIfStatement(const JSTokenLocation&, int, int, int, int, int) { return StatementResult; }
      int createForLoop(const JSTokenLocation&, int, int, int, int, int, int, VariableEnvironment&) { return StatementResult; }
      int createForInLoop(const JSTokenLocation&, int, int, int, const JSTokenLocation&, int, int, int, int, int, VariableEnvironment&) { return StatementResult; }
      int createForOfLoop(bool, const JSTokenLocation&, int, int, int, const JSTokenLocation&, int, int, int, int, int, VariableEnvironment&) { return StatementResult; }
      int createEmptyStatement(const JSTokenLocation&) { return StatementResult; }
      int createDeclarationStatement(const JSTokenLocation&, int, int, int) { return StatementResult; }
      int createReturnStatement(const JSTokenLocation&, int, int, int) { return StatementResult; }
      int createBreakStatement(const JSTokenLocation&, int, int) { return StatementResult; }
      int createBreakStatement(const JSTokenLocation&, const Identifier*, int, int) { return StatementResult; }
      int createContinueStatement(const JSTokenLocation&, int, int) { return StatementResult; }
      int createContinueStatement(const JSTokenLocation&, const Identifier*, int, int) { return StatementResult; }
      int createTryStatement(const JSTokenLocation&, int, int, int, int, int, int, VariableEnvironment&) { return StatementResult; }
      int createSwitchStatement(const JSTokenLocation&, int, int, int, int, int, int, VariableEnvironment&, DeclarationStacks::FunctionStack&&) { return StatementResult; }
      int createWhileStatement(const JSTokenLocation&, int, int, int, int) { return StatementResult; }
      int createWithStatement(const JSTokenLocation&, int, int, int, int, int, int) { return StatementResult; }
      int createDoWhileStatement(const JSTokenLocation&, int, int, int, int) { return StatementResult; }
      int createLabelStatement(const JSTokenLocation&, const Identifier*, int, int, int) { return StatementResult; }
      int createThrowStatement(const JSTokenLocation&, int, int, int) { return StatementResult; }
      int createDebugger(const JSTokenLocation&, int, int) { return StatementResult; }
      int createConstStatement(const JSTokenLocation&, int, int, int) { return StatementResult; }
      int createModuleName(const JSTokenLocation&, const Identifier&) { return ModuleNameResult; }
      ImportSpecifier createImportSpecifier(const JSTokenLocation&, const Identifier&, const Identifier&) { return ImportSpecifierResult; }
      ImportSpecifierList createImportSpecifierList() { return ImportSpecifierListResult; }
      void appendImportSpecifier(ImportSpecifierList, ImportSpecifier) { }
      int createImportDeclaration(const JSTokenLocation&, ImportSpecifierList, ModuleName) { return StatementResult; }
      int createExportAllDeclaration(const JSTokenLocation&, ModuleName) { return StatementResult; }
      int createExportDefaultDeclaration(const JSTokenLocation&, int, const Identifier&) { return StatementResult; }
      int createExportLocalDeclaration(const JSTokenLocation&, int) { return StatementResult; }
      int createExportNamedDeclaration(const JSTokenLocation&, ExportSpecifierList, ModuleName) { return StatementResult; }
      ExportSpecifier createExportSpecifier(const JSTokenLocation&, const Identifier&, const Identifier&) { return ExportSpecifierResult; }
      ExportSpecifierList createExportSpecifierList() { return ExportSpecifierListResult; }
      void appendExportSpecifier(ExportSpecifierList, ExportSpecifier) { }
  
      int appendConstDecl(const JSTokenLocation&, int, const Identifier*, int) { return StatementResult; }
      Property createGetterOrSetterProperty(const JSTokenLocation&, PropertyNode::Type type, bool strict, const Identifier* name, const ParserFunctionInfo<SyntaxChecker>&, ClassElementTag)
      {
          ASSERT(name);
          if (!strict)
              return Property(type);
          return Property(name, type);
      }
      Property createGetterOrSetterProperty(const JSTokenLocation&, PropertyNode::Type type, bool, int, const ParserFunctionInfo<SyntaxChecker>&, ClassElementTag)
      {
          return Property(type);
      }
      Property createGetterOrSetterProperty(VM& vm, ParserArena& parserArena, const JSTokenLocation&, PropertyNode::Type type, bool strict, double name, const ParserFunctionInfo<SyntaxChecker>&, ClassElementTag)
      {
          if (!strict)
              return Property(type);
          return Property(&parserArena.identifierArena().makeNumericIdentifier(vm, name), type);
      }
  
      void appendStatement(int, int) { }
      int combineCommaNodes(const JSTokenLocation&, int, int) { return CommaExpr; }
      int evalCount() const { return 0; }
      void appendBinaryExpressionInfo(int& operandStackDepth, int expr, int, int, int, bool)
      {
          if (!m_topBinaryExpr)
              m_topBinaryExpr = expr;
          else
              m_topBinaryExpr = BinaryExpr;
          operandStackDepth++;
      }
      
      // Logic to handle datastructures used during parsing of binary expressions
      void operatorStackPop(int& operatorStackDepth) { operatorStackDepth--; }
      bool operatorStackShouldReduce(int) { return true; }
      BinaryOperand getFromOperandStack(int) { return m_topBinaryExpr; }
      void shrinkOperandStackBy(int& operandStackDepth, int amount) { operandStackDepth -= amount; }
      void appendBinaryOperation(const JSTokenLocation&, int& operandStackDepth, int&, BinaryOperand, BinaryOperand) { operandStackDepth++; }
      void operatorStackAppend(int& operatorStackDepth, int, int) { operatorStackDepth++; }
      int popOperandStack(int&) { int res = m_topBinaryExpr; m_topBinaryExpr = 0; return res; }
      
      void appendUnaryToken(int& stackDepth, int tok, int) { stackDepth = 1; m_topUnaryToken = tok; }
      int unaryTokenStackLastType(int&) { return m_topUnaryToken; }
      JSTextPosition unaryTokenStackLastStart(int&) { return JSTextPosition(0, 0, 0); }
      void unaryTokenStackRemoveLast(int& stackDepth) { stackDepth = 0; }
      
      void assignmentStackAppend(int, int, int, int, int, Operator) { }
      int createAssignment(const JSTokenLocation&, int, int, int, int, int) { RELEASE_ASSERT_NOT_REACHED(); return AssignmentExpr; }
      const Identifier* getName(const Property& property) const { return property.name; }
      PropertyNode::Type getType(const Property& property) const { return property.type; }
      bool isResolve(ExpressionType expr) const { return expr == ResolveExpr || expr == ResolveEvalExpr; }
      ExpressionType createDestructuringAssignment(const JSTokenLocation&, int, ExpressionType)
      {
          return DestructuringAssignment;
      }
      
      ArrayPattern createArrayPattern(const JSTokenLocation&)
      {
          return ArrayDestructuring;
      }
      void appendArrayPatternSkipEntry(ArrayPattern, const JSTokenLocation&)
      {
      }
      void appendArrayPatternEntry(ArrayPattern, const JSTokenLocation&, DestructuringPattern, int)
      {
      }
      void appendArrayPatternRestEntry(ArrayPattern, const JSTokenLocation&, DestructuringPattern)
      {
      }
      void finishArrayPattern(ArrayPattern, const JSTextPosition&, const JSTextPosition&, const JSTextPosition&)
      {
      }
      ObjectPattern createObjectPattern(const JSTokenLocation&)
      {
          return ObjectDestructuring;
      }
      void appendObjectPatternEntry(ObjectPattern, const JSTokenLocation&, bool, const Identifier&, DestructuringPattern, int)
      {
      }
      void appendObjectPatternEntry(VM&, ObjectPattern, const JSTokenLocation&, Expression, DestructuringPattern, Expression)
      {
      }
      void appendObjectPatternRestEntry(VM&, ObjectPattern, const JSTokenLocation&, DestructuringPattern)
      {
      }
      void setContainsObjectRestElement(ObjectPattern, bool)
      {
      }
      void setContainsComputedProperty(ObjectPattern, bool)
      {
      }
  
      DestructuringPattern createBindingLocation(const JSTokenLocation&, const Identifier&, const JSTextPosition&, const JSTextPosition&, AssignmentContext)
      {
          return BindingDestructuring;
      }
      RestPattern createRestParameter(DestructuringPattern, size_t)
      { 
          return RestParameter;
      }
      DestructuringPattern createAssignmentElement(const Expression&, const JSTextPosition&, const JSTextPosition&)
      {
          return BindingDestructuring;
      }
  
      bool isBindingNode(DestructuringPattern pattern)
      {
          return pattern == BindingDestructuring;
      }
  
      bool isLocation(ExpressionType type)
      {
          return type == ResolveExpr || type == DotExpr || type == BracketExpr;
      }
  
      bool isAssignmentLocation(ExpressionType type)
      {
          return isLocation(type) || type == DestructuringAssignment;
      }
  
      bool isObjectLiteral(ExpressionType type)
      {
          return type == ObjectLiteralExpr;
      }
  
      bool isArrayLiteral(ExpressionType type)
      {
          return type == ArrayLiteralExpr;
      }
  
      bool isObjectOrArrayLiteral(ExpressionType type)
      {
          return isObjectLiteral(type) || isArrayLiteral(type);
      }
  
      bool isFunctionCall(ExpressionType type)
      {
          return type == CallExpr;
      }
  
      bool shouldSkipPauseLocation(int) const { return true; }
  
      void setEndOffset(int, int) { }
      int endOffset(int) { return 0; }
      void setStartOffset(int, int) { }
  
      JSTextPosition breakpointLocation(int) { return JSTextPosition(-1, 0, 0); }
  
      void propagateArgumentsUse() { }
  
  private:
      int m_topBinaryExpr;
      int m_topUnaryToken;
  };
  
  } // namespace JSC
  