Writing Your First Visual Studio Language Service

#region License
/* **********************************************************************************
 * Copyright (c) Roman Ivantsov
 * This source code is subject to terms and conditions of the MIT License
 * for Irony. A copy of the license can be found in the License.txt file
 * at the root of this distribution. 
 * By using this source code in any fashion, you are agreeing to be bound by the terms of the 
 * MIT License.
 * You must not remove this notice from this software.
 * **********************************************************************************/
#endregion

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Irony.Runtime;

namespace Irony.Compiler.AST {
  public class BinExprNode : AstNode {
    public AstNode Left;
    public string Op;
    public AstNode Right;
    CallDispatcher _dispatcher;


    public BinExprNode(NodeArgs args, AstNode left, string op, AstNode right) : base(args) {
      ChildNodes.Clear();
      Left = left;
      AddChild("Arg", Left);
      Op = op; 
      Right = right;
      AddChild("Arg", Right);
      //Flags |= AstNodeFlags.TypeBasedDispatch;
    }
    public BinExprNode(NodeArgs args) 
      : this(args, args.ChildNodes[0], args.ChildNodes[1].GetContent(), args.ChildNodes[2]) {  }

    public override void OnCodeAnalysis(CodeAnalysisArgs args) {
      switch (args.Phase) {
        case CodeAnalysisPhase.Binding:
          _dispatcher = args.Context.Runtime.GetDispatcher(Op);
          if (_dispatcher == null)
            args.Context.ReportError(this.Location, "Operator " + Op + " not defined.");
          break;
      }//switch
      base.OnCodeAnalysis(args);
    }

    protected override void DoEvaluate(EvaluationContext context) {
      try {
        Left.Evaluate(context);
        object arg1 = context.CurrentResult;
        Right.Evaluate(context);
        context.Arg2 = context.CurrentResult;
        context.Arg1 = arg1;
        _dispatcher.Evaluate(context);
      } catch (RuntimeException e) {
        e.Location = this.Location;
        throw; 
      }
    }

    public override string ToString() {
      return Op + " (binary operation)";
    }
    protected override void XmlSetAttributes(System.Xml.XmlElement thisElement) {
      base.XmlSetAttributes(thisElement);
      thisElement.SetAttribute("Operation", this.Op); 
    }
  }//class
}//namespace