#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 RangeExpression : Expression
{
private readonly Expression _from;
private readonly Expression _to;
public RangeExpression(TokenPosition tokenPosition, Expression from, Expression to) : base(tokenPosition)
{
_from = from;
_to = to;
}
public override ValueExpression Evaluate(IParserContext context)
{
ValueExpression from = _from.Evaluate(context);
ValueExpression to = _to.Evaluate(context);
if (from.Type != typeof(int) && from.Type != typeof(long))
throw new ExpressionEvaluationException("Expression " + from + " does not evaluate to int or long", from);
if (to.Type != typeof(int) && to.Type != typeof(long))
throw new ExpressionEvaluationException("Expression " + from + " does not evaluate to int or long", from);
if (from.Type == typeof(long) || to.Type == typeof(long))
return Exp.Value(TokenPosition, Range((long)Convert.ChangeType(from.Value, typeof(long)), (long)Convert.ChangeType(to.Value, typeof(long))));
else
return Exp.Value(TokenPosition, Range((int)Convert.ChangeType(from.Value, typeof(int)), (int)Convert.ChangeType(to.Value, typeof(int))));
}
public static IEnumerable<int> Range(int from, int to)
{
if (from == to)
yield return from;
else if (from < to)
for (int i = from; i <= to; i++)
yield return i;
else
for (int i = from; i >= to; i--)
yield return i;
}
public static IEnumerable<long> Range(long from, long to)
{
if (from == to)
yield return from;
else if (from < to)
for (long i = from; i <= to; i++)
yield return i;
else
for (long i = from; i >= to; i--)
yield return i;
}
}
}
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