#region License
//=============================================================================
// Vici Core - Productivity Library for .NET 3.5
//
// Copyright (c) 2008-2010 Philippe Leybaert
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//=============================================================================
#endregion
using System;
using System.Collections.Generic;
namespace Vici.Core.Parser{
public class AsExpression : Expression
{
private readonly Expression _objectExpression;
private readonly Expression _typeExpression;
public AsExpression(TokenPosition position, Expression objectExpression, Expression typeExpression) : base(position)
{
_objectExpression = objectExpression;
_typeExpression = typeExpression;
}
public override ValueExpression Evaluate(IParserContext context)
{
ClassName className = _typeExpression.Evaluate(context).Value as ClassName;
if (className == null)
throw new IllegalOperandsException("as operator requires type. " + _typeExpression + " is not a type",this);
Type checkType = className.Type;
ValueExpression objectValue = _objectExpression.Evaluate(context);
Type objectType = objectValue.Type;
if (objectValue.Value == null)
return Exp.Value(TokenPosition, null, checkType);
objectType = Nullable.GetUnderlyingType(objectType) ?? objectType;
if (!objectType.IsValueType)
return Exp.Value(TokenPosition, objectValue.Value, checkType);
if ((Nullable.GetUnderlyingType(checkType) ?? checkType) == objectType)
return Exp.Value(TokenPosition, objectValue.Value, checkType);
return Exp.Value(TokenPosition, null, checkType);
}
}
}
|