source: stable/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory.CSharp-5.5.0/Ast/Expressions/Expression.cs

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using System;
using System.Collections.Generic;

namespace ICSharpCode.NRefactory.CSharp
{
  /// <summary>
  /// Base class for expressions.
  /// </summary>
  /// <remarks>
  /// This class is useful even though it doesn't provide any additional functionality:
  /// It can be used to communicate more information in APIs, e.g. "this subnode will always be an expression"
  /// </remarks>
  public abstract class Expression : AstNode
  {
    #region Null
    public new static readonly Expression Null = new NullExpression ();
    
    sealed class NullExpression : Expression
    {
      public override bool IsNull {
        get {
          return true;
        }
      }
      
      public override void AcceptVisitor (IAstVisitor visitor)
      {
        visitor.VisitNullNode(this);
      }
      
      public override T AcceptVisitor<T> (IAstVisitor<T> visitor)
      {
        return visitor.VisitNullNode(this);
      }
      
      public override S AcceptVisitor<T, S> (IAstVisitor<T, S> visitor, T data)
      {
        return visitor.VisitNullNode(this, data);
      }
      
      protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
      {
        return other == null || other.IsNull;
      }
    }
    #endregion
    
    #region PatternPlaceholder
    public static implicit operator Expression(PatternMatching.Pattern pattern)
    {
      return pattern != null ? new PatternPlaceholder(pattern) : null;
    }
    
    sealed class PatternPlaceholder : Expression, PatternMatching.INode
    {
      readonly PatternMatching.Pattern child;
      
      public PatternPlaceholder(PatternMatching.Pattern child)
      {
        this.child = child;
      }
      
      public override NodeType NodeType {
        get { return NodeType.Pattern; }
      }
      
      public override void AcceptVisitor (IAstVisitor visitor)
      {
        visitor.VisitPatternPlaceholder(this, child);
      }
        
      public override T AcceptVisitor<T> (IAstVisitor<T> visitor)
      {
        return visitor.VisitPatternPlaceholder(this, child);
      }
      
      public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
      {
        return visitor.VisitPatternPlaceholder(this, child, data);
      }
      
      protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
      {
        return child.DoMatch(other, match);
      }
      
      bool PatternMatching.INode.DoMatchCollection(Role role, PatternMatching.INode pos, PatternMatching.Match match, PatternMatching.BacktrackingInfo backtrackingInfo)
      {
        return child.DoMatchCollection(role, pos, match, backtrackingInfo);
      }
    }
    #endregion
    
    public override NodeType NodeType {
      get {
        return NodeType.Expression;
      }
    }
    
    public new Expression Clone()
    {
      return (Expression)base.Clone();
    }

    public Expression ReplaceWith(Func<Expression, Expression> replaceFunction)
    {
      if (replaceFunction == null)
        throw new ArgumentNullException("replaceFunction");
      return (Expression)base.ReplaceWith(node => replaceFunction((Expression)node));
    }
    
    #region Builder methods
    /// <summary>
    /// Builds an member reference expression using this expression as target.
    /// </summary>
    public virtual MemberReferenceExpression Member(string memberName)
    {
      return new MemberReferenceExpression { Target = this, MemberName = memberName };
    }
    
    /// <summary>
    /// Builds an indexer expression using this expression as target.
    /// </summary>
    public virtual IndexerExpression Indexer(IEnumerable<Expression> arguments)
    {
      IndexerExpression expr = new IndexerExpression();
      expr.Target = this;
      expr.Arguments.AddRange(arguments);
      return expr;
    }
    
    /// <summary>
    /// Builds an indexer expression using this expression as target.
    /// </summary>
    public virtual IndexerExpression Indexer(params Expression[] arguments)
    {
      IndexerExpression expr = new IndexerExpression();
      expr.Target = this;
      expr.Arguments.AddRange(arguments);
      return expr;
    }
    
    /// <summary>
    /// Builds an invocation expression using this expression as target.
    /// </summary>
    public virtual InvocationExpression Invoke(string methodName, IEnumerable<Expression> arguments)
    {
      return Invoke(methodName, null, arguments);
    }
    
    /// <summary>
    /// Builds an invocation expression using this expression as target.
    /// </summary>
    public virtual InvocationExpression Invoke(string methodName, params Expression[] arguments)
    {
      return Invoke(methodName, null, arguments);
    }
    
    /// <summary>
    /// Builds an invocation expression using this expression as target.
    /// </summary>
    public virtual InvocationExpression Invoke(string methodName, IEnumerable<AstType> typeArguments, IEnumerable<Expression> arguments)
    {
      InvocationExpression ie = new InvocationExpression();
      MemberReferenceExpression mre = new MemberReferenceExpression();
      mre.Target = this;
      mre.MemberName = methodName;
      mre.TypeArguments.AddRange(typeArguments);
      ie.Target = mre;
      ie.Arguments.AddRange(arguments);
      return ie;
    }
    
    /// <summary>
    /// Builds an invocation expression using this expression as target.
    /// </summary>
    public virtual InvocationExpression Invoke(IEnumerable<Expression> arguments)
    {
      InvocationExpression ie = new InvocationExpression();
      ie.Target = this;
      ie.Arguments.AddRange(arguments);
      return ie;
    }
    
    /// <summary>
    /// Builds an invocation expression using this expression as target.
    /// </summary>
    public virtual InvocationExpression Invoke(params Expression[] arguments)
    {
      InvocationExpression ie = new InvocationExpression();
      ie.Target = this;
      ie.Arguments.AddRange(arguments);
      return ie;
    }
    
    public virtual CastExpression CastTo(AstType type)
    {
      return new CastExpression { Type = type,  Expression = this };
    }
    
    public virtual AsExpression CastAs(AstType type)
    {
      return new AsExpression { Type = type,  Expression = this };
    }
    
    public virtual IsExpression IsType(AstType type)
    {
      return new IsExpression { Type = type,  Expression = this };
    }
    #endregion
  }
}