added marr.datamapper source code for easy debugging.

Marr.Data/QGen/ExpressionVisitor.cs

@@ -0,0 +1,149 @@
+/* This class was copied from Mehfuz's LinqExtender project, which is available from github.
+ * http://mehfuzh.github.com/LinqExtender/
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Linq.Expressions;
+
+namespace Marr.Data.QGen
+{
+    ///<summary>
+    /// Expression visitor 
+    ///</summary>
+    public class ExpressionVisitor
+    {
+        /// <summary>
+        /// Visits expression and delegates call to different to branch.
+        /// </summary>
+        /// <param name="expression"></param>
+        /// <returns></returns>
+        protected virtual Expression Visit(Expression expression)
+        {
+            if (expression == null)
+                return null;
+
+            switch (expression.NodeType)
+            {
+                case ExpressionType.Lambda:
+                    return VisitLamda((LambdaExpression)expression);
+                case ExpressionType.ArrayLength:
+                case ExpressionType.Convert:
+                case ExpressionType.ConvertChecked:
+                case ExpressionType.Negate:
+                case ExpressionType.UnaryPlus:
+                case ExpressionType.NegateChecked:
+                case ExpressionType.Not:
+                case ExpressionType.Quote:
+                case ExpressionType.TypeAs:
+                    return this.VisitUnary((UnaryExpression)expression);
+                case ExpressionType.Add:
+                case ExpressionType.AddChecked:
+                case ExpressionType.And:
+                case ExpressionType.AndAlso:
+                case ExpressionType.ArrayIndex:
+                case ExpressionType.Coalesce:
+                case ExpressionType.Divide:
+                case ExpressionType.Equal:
+                case ExpressionType.ExclusiveOr:
+                case ExpressionType.GreaterThan:
+                case ExpressionType.GreaterThanOrEqual:
+                case ExpressionType.LeftShift:
+                case ExpressionType.LessThan:
+                case ExpressionType.LessThanOrEqual:
+                case ExpressionType.Modulo:
+                case ExpressionType.Multiply:
+                case ExpressionType.MultiplyChecked:
+                case ExpressionType.NotEqual:
+                case ExpressionType.Or:
+                case ExpressionType.OrElse:
+                case ExpressionType.Power:
+                case ExpressionType.RightShift:
+                case ExpressionType.Subtract:
+                case ExpressionType.SubtractChecked:
+                    return this.VisitBinary((BinaryExpression)expression);
+                case ExpressionType.Call:
+                    return this.VisitMethodCall((MethodCallExpression)expression);
+                case ExpressionType.Constant:
+                    return this.VisitConstant((ConstantExpression)expression);
+                case ExpressionType.MemberAccess:
+                    return this.VisitMemberAccess((MemberExpression)expression);
+                case ExpressionType.Parameter:
+                    return this.VisitParameter((ParameterExpression)expression);
+
+            }
+            throw new ArgumentOutOfRangeException("expression", expression.NodeType.ToString());
+        }
+
+        /// <summary>
+        /// Visits the constance expression. To be implemented by user.
+        /// </summary>
+        /// <param name="expression"></param>
+        /// <returns></returns>
+        protected virtual Expression VisitConstant(ConstantExpression expression)
+        {
+            return expression;
+        }
+
+        /// <summary>
+        /// Visits the memeber access expression. To be implemented by user.
+        /// </summary>
+        /// <param name="expression"></param>
+        /// <returns></returns>
+        protected virtual Expression VisitMemberAccess(MemberExpression expression)
+        {
+            return expression;
+        }
+
+        /// <summary>
+        /// Visits the method call expression. To be implemented by user.
+        /// </summary>
+        /// <param name="expression"></param>
+        /// <returns></returns>
+        protected virtual Expression VisitMethodCall(MethodCallExpression expression)
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <summary>
+        /// Visits the binary expression.
+        /// </summary>
+        /// <param name="expression"></param>
+        /// <returns></returns>
+        protected virtual Expression VisitBinary(BinaryExpression expression)
+        {
+            this.Visit(expression.Left);
+            this.Visit(expression.Right);
+            return expression;
+        }
+
+        /// <summary>
+        /// Visits the unary expression.
+        /// </summary>
+        /// <param name="expression"></param>
+        /// <returns></returns>
+        protected virtual Expression VisitUnary(UnaryExpression expression)
+        {
+            this.Visit(expression.Operand);
+            return expression;
+        }
+
+        /// <summary>
+        /// Visits the lamda expression.
+        /// </summary>
+        /// <param name="lambdaExpression"></param>
+        /// <returns></returns>
+        protected virtual Expression VisitLamda(LambdaExpression lambdaExpression)
+        {
+            this.Visit(lambdaExpression.Body);
+            return lambdaExpression;
+        }
+
+        private Expression VisitParameter(ParameterExpression expression)
+        {
+            return expression;
+        }
+    }
+}