Expression.cs

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// -------------------------------------------------------------------------- //
// Project rROTOR                                                             //
// -------------------------------------------------------------------------- //
// File: Expression.cs                                                        //
// Author: Cristina Gonzalez Muñoz  -  cristi.gm@gmail.com                    //
// Description:                                                               //
//    Abstract class encapsulate a programming language expression.           //
//    Inheritance: Statement.                                                 //
//    Implements Composite pattern [Composite].                               //
//    Implements Visitor pattern [Element].                                   //
// -------------------------------------------------------------------------- //
// Create date: 04-12-2006                                                    //
// Modification date: 09-04-2007                                              //

using System;
using System.Collections.Generic;
using System.Text;

using Tools;
using TypeSystem;

using ErrorManagement;
using AST.Operations;

namespace AST
{
   public abstract class Expression : Statement
   {
      #region Fields

      private TypeExpression expressionType;

      private bool lvalue;

      private bool leftExpression = false;

      protected TypeExpression frozenTypeExpression;

      #endregion

      #region Properties

      public TypeExpression ExpressionType 
      {
         get { return this.expressionType; }
         set { this.expressionType = value; }
      }

      public bool Lvalue
      {
         get { return this.lvalue; }
         set { this.lvalue = value; }
      }

      public bool LeftExpression
      {
         get { return this.leftExpression; }
         set { this.leftExpression = value; }
      }

      public virtual TypeExpression ILTypeExpression
      {
         get 
         {
            if (this.frozenTypeExpression != null)
               return this.frozenTypeExpression;
            else
               return this.expressionType;
         }
      }

      #endregion

      #region Constructor

      protected Expression(Location location):base(location)
      { 
      }

      #endregion

      #region CloneInit()

      public Expression CloneInit()
      {
         return (Expression)this.MemberwiseClone();
      }

      #endregion

      #region Dispatcher AstOperation
      public override object AcceptOperation(AstOperation op, object arg) {
          return op.Exec(this, arg);
      }

      #endregion
   }
}