Merged pull request adding support for LINQ from VB.NET.

Author: Robert Stam

.gitignore

@@ -5,6 +5,7 @@ obj
 *.suo
 *.vsp
 *.csproj.VisualState.xml
+*.vbproj.VisualState.xml
 *.cache
 
 # MonoDevelop artifacts

Driver/Linq/Expressions/ExpressionNormalizer.cs

@@ -51,9 +51,15 @@ public static Expression Normalize(Expression node)
  return normalizer.Visit(node);
  }
 
+ // protected methods
+ /// <summary>
+ /// Visits a BinaryExpression.
+ /// </summary>
+ /// <param name="node">The BinaryExpression.</param>
+ /// <returns>The BinaryExpression (possibly modified).</returns>
  protected override Expression VisitBinary(BinaryExpression node)
  {
- node = FlipBinaryExpression(node);
+ node = EnsureConstantIsOnRight(node);
 
  Expression result = null;
  if (node.Left.NodeType == ExpressionType.Call && node.Right.NodeType == ExpressionType.Constant)
@@ -62,13 +68,13 @@ protected override Expression VisitBinary(BinaryExpression node)
  var constant = (ConstantExpression)node.Right;
  if (mex.Method.DeclaringType.FullName == "Microsoft.VisualBasic.CompilerServices.Operators")
  {
- //VB creates expression trees with "special" operators
+ // VB creates expression trees with "special" operators
  result = VisitVBCompilerServicesOperators(mex, node.NodeType, constant);
  }
  else if (mex.Method.DeclaringType == typeof(string) && mex.Method.Name == "get_Chars" && constant.Type == typeof(char))
  {
- //VB creates string index expressions using character comparison whereas C# uses ascii value comparison
- //So, we make VB's string index comparison look like C#.
+ // VB creates string index expressions using character comparison whereas C# uses ascii value comparison
+ // so, we make VB's string index comparison look like C#
  result = Expression.MakeBinary(
  node.NodeType,
  Expression.Convert(mex, typeof(int)),
@@ -84,27 +90,33 @@ protected override Expression VisitBinary(BinaryExpression node)
  return base.VisitBinary(node);
  }
 
+ /// <summary>
+ /// Visits a UnaryExpression.
+ /// </summary>
+ /// <param name="node">The UnaryExpression.</param>
+ /// <returns>The UnaryExpression (possibly modified).</returns>
  protected override Expression VisitUnary(UnaryExpression node)
  {
  if (node.NodeType == ExpressionType.Convert)
  {
  if (node.Type.IsAssignableFrom(node.Operand.Type))
  {
+ // ignore the unnecessary conversion added by VB
  return Visit(node.Operand);
  }
  }
 
  return base.VisitUnary(node);
  }
 
- private BinaryExpression FlipBinaryExpression(BinaryExpression node)
+ private BinaryExpression EnsureConstantIsOnRight(BinaryExpression node)
  {
  var left = node.Left;
  var right = node.Right;
  var operatorType = node.NodeType;
  if (left.NodeType == ExpressionType.Constant)
  {
- right = node.Left as ConstantExpression;
+ right = node.Left;
  left = node.Right;
  // if the constant was on the left some operators need to be flipped
  switch (operatorType)