websitepanel/WebsitePanel/Sources/WebsitePanel.Templates/AST/UnaryExpression.cs
2011-07-13 16:07:32 -07:00

81 lines
3.1 KiB
C#

// Copyright (c) 2011, Outercurve Foundation.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// - Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
//
// - Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// - Neither the name of the Outercurve Foundation nor the names of its
// contributors may be used to endorse or promote products derived from this
// software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
// ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
using System;
using System.Collections.Generic;
using System.Text;
namespace WebsitePanel.Templates.AST
{
internal class UnaryExpression : Expression
{
Expression rhs;
TokenType op;
public UnaryExpression(int line, int column, TokenType op, Expression rhs)
: base(line, column)
{
this.op = op;
this.rhs = rhs;
}
public TokenType Operator
{
get { return op; }
}
Expression RightExpression
{
get { return rhs; }
set { rhs = value; }
}
public override object Eval(TemplateContext context)
{
// evaluate right side
object val = rhs.Eval(context);
if (op == TokenType.Minus && val is Decimal)
return -(Decimal)val;
else if (op == TokenType.Minus && val is Int32)
return -(Int32)val;
else if (op == TokenType.Not && val is Boolean)
return !(Boolean)val;
throw new ParserException("Unary operator can be applied to integer, decimal and boolean expressions.", Line, Column);
}
public override string ToString()
{
StringBuilder sb = new StringBuilder();
sb.Append(Operator).Append("(").Append(RightExpression).Append(")");
return sb.ToString();
}
}
}