public static Expression FoldBinary(BinaryExpression inputExpression)
{
Expression left = ConstantFolding.Fold(inputExpression.Left);
Expression right = ConstantFolding.Fold(inputExpression.Right);
LambdaExpression conversion = ConstantFolding.FoldLambda(inputExpression.Conversion);
Expression resultExpression;
if (left != inputExpression.Left || right != inputExpression.Right || conversion != inputExpression.Conversion)
{
if (inputExpression.NodeType == ExpressionType.Coalesce)
{
resultExpression = Expression.Coalesce(left, right, conversion);
}
else
{
resultExpression = Expression.MakeBinary(inputExpression.NodeType, left, right, inputExpression.IsLiftedToNull, inputExpression.Method);
}
}
else
{
resultExpression = inputExpression;
}
if (IsConstant(left) && inputExpression.NodeType == ExpressionType.Coalesce)
{
object leftValue = ExpressionSimplifier.Evaluate(left);
if (leftValue == null)
{
resultExpression = right;
}
else
{
resultExpression = Expression.Constant(leftValue);
}
}
else if (IsConstant(left) && IsConstant(right))
{
resultExpression = ExpressionSimplifier.EvaluateToExpression(resultExpression);
}
return(resultExpression);
}
public static Expression Fold(Expression inputExpression)
{
if (inputExpression == null)
{
return(inputExpression);
}
switch (inputExpression.NodeType)
{
case ExpressionType.Negate:
case ExpressionType.NegateChecked:
case ExpressionType.Not:
case ExpressionType.Convert:
case ExpressionType.ConvertChecked:
case ExpressionType.ArrayLength:
case ExpressionType.Quote:
case ExpressionType.TypeAs:
case ExpressionType.UnaryPlus:
case ExpressionType.OnesComplement:
case ExpressionType.Increment:
case ExpressionType.Decrement:
return(ConstantFolding.FoldUnary((UnaryExpression)inputExpression));
case ExpressionType.Add:
case ExpressionType.AddChecked:
case ExpressionType.Subtract:
case ExpressionType.SubtractChecked:
case ExpressionType.Multiply:
case ExpressionType.MultiplyChecked:
case ExpressionType.Divide:
case ExpressionType.Modulo:
case ExpressionType.And:
case ExpressionType.AndAlso:
case ExpressionType.Or:
case ExpressionType.OrElse:
case ExpressionType.LessThan:
case ExpressionType.LessThanOrEqual:
case ExpressionType.GreaterThan:
case ExpressionType.GreaterThanOrEqual:
case ExpressionType.Equal:
case ExpressionType.NotEqual:
case ExpressionType.Coalesce:
case ExpressionType.ArrayIndex:
case ExpressionType.RightShift:
case ExpressionType.LeftShift:
case ExpressionType.ExclusiveOr:
return(ConstantFolding.FoldBinary((BinaryExpression)inputExpression));
case ExpressionType.TypeIs:
return(ConstantFolding.FoldTypeIs((TypeBinaryExpression)inputExpression));
case ExpressionType.Conditional:
return(ConstantFolding.FoldConditional((ConditionalExpression)inputExpression));
case ExpressionType.Constant:
return(inputExpression);
case ExpressionType.Parameter:
return(ConstantFolding.FoldParameter((ParameterExpression)inputExpression));
case ExpressionType.MemberAccess:
return(ConstantFolding.FoldMemberAccess((MemberExpression)inputExpression));
case ExpressionType.Call:
return(ConstantFolding.FoldMethodCall((MethodCallExpression)inputExpression));
case ExpressionType.Lambda:
return(ConstantFolding.FoldLambda((LambdaExpression)inputExpression));
case ExpressionType.New:
return(ConstantFolding.FoldNew((NewExpression)inputExpression));
case ExpressionType.NewArrayInit:
case ExpressionType.NewArrayBounds:
return(ConstantFolding.FoldNewArray((NewArrayExpression)inputExpression));
case ExpressionType.Invoke:
return(ConstantFolding.FoldInvocation((InvocationExpression)inputExpression));
case ExpressionType.MemberInit:
return(ConstantFolding.FoldMemberInit((MemberInitExpression)inputExpression));
case ExpressionType.ListInit:
return(ConstantFolding.FoldListInit((ListInitExpression)inputExpression));
default:
throw new DocumentQueryException(string.Format(CultureInfo.CurrentUICulture,
"Unhandled expression type: '{0}'", inputExpression.NodeType));
}
}
