source: branches/2990_VariableImpactBasedFeatureSelection/HeuristicLab.ExtLibs/HeuristicLab.EPPlus/4.0.3/EPPlus-4.0.3/FormulaParsing/ExpressionGraph/DecimalExpression.cs

using System;
using System.Collections.Generic;
/*******************************************************************************
 * You may amend and distribute as you like, but don't remove this header!
 *
 * EPPlus provides server-side generation of Excel 2007/2010 spreadsheets.
 * See http://www.codeplex.com/EPPlus for details.
 *
 * Copyright (C) 2011  Jan Källman
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.

 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
 * See the GNU Lesser General Public License for more details.
 *
 * The GNU Lesser General Public License can be viewed at http://www.opensource.org/licenses/lgpl-license.php
 * If you unfamiliar with this license or have questions about it, here is an http://www.gnu.org/licenses/gpl-faq.html
 *
 * All code and executables are provided "as is" with no warranty either express or implied. 
 * The author accepts no liability for any damage or loss of business that this product may cause.
 *
 * Code change notes:
 * 
 * Author             Change            Date
 * ******************************************************************************
 * Mats Alm                       Added                   2013-03-01 (Prior file history on https://github.com/swmal/ExcelFormulaParser)
 *******************************************************************************/
using System.Linq;
using System.Text;
using System.Globalization;

namespace OfficeOpenXml.FormulaParsing.ExpressionGraph
{
    public class DecimalExpression : AtomicExpression
    {
        private readonly double? _compiledValue;
        private readonly bool _negate;

        public DecimalExpression(string expression)
            : this(expression, false)
        {
            
        }

        public DecimalExpression(string expression, bool negate)
            : base(expression)
        {
            _negate = negate;
        }

        public DecimalExpression(double compiledValue)
            : base(compiledValue.ToString(CultureInfo.InvariantCulture))
        {
            _compiledValue = compiledValue;
        }

        public override CompileResult Compile()
        {
            double result = _compiledValue.HasValue ? _compiledValue.Value : double.Parse(ExpressionString, CultureInfo.InvariantCulture);
            result = _negate ? result * -1 : result;
            return new CompileResult(result, DataType.Decimal);
        }
    }
}