source: branches/2817-BinPackingSpeedup/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory.CSharp-5.5.0/Ast/Statements/Statement.cs

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// 
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using System;

namespace ICSharpCode.NRefactory.CSharp
{
  /// <summary>
  /// Base class for statements.
  /// </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 a statement"
  /// </remarks>
  public abstract class Statement : AstNode
  {
    #region Null
    public new static readonly Statement Null = new NullStatement ();
    
    sealed class NullStatement : Statement
    {
      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 Statement(PatternMatching.Pattern pattern)
    {
      return pattern != null ? new PatternPlaceholder(pattern) : null;
    }
    
    sealed class PatternPlaceholder : Statement, 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 new Statement Clone()
    {
      return (Statement)base.Clone();
    }
    
    public Statement ReplaceWith(Func<Statement, Statement> replaceFunction)
    {
      if (replaceFunction == null)
        throw new ArgumentNullException("replaceFunction");
      return (Statement)base.ReplaceWith(node => replaceFunction((Statement)node));
    }
    
    public override NodeType NodeType {
      get { return NodeType.Statement; }
    }

    public static implicit operator Statement (Expression type)
    {
      return new ExpressionStatement(type);
    }
  }
}