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/*************************************************************************
** Calculator.hpp **
** **
** This file is part of dvisvgm -- a fast DVI to SVG converter **
** Copyright (C) 2005-2019 Martin Gieseking <martin.gieseking@uos.de> **
** **
** This program is free software; you can redistribute it and/or **
** modify it under the terms of the GNU General Public License as **
** published by the Free Software Foundation; either version 3 of **
** the License, or (at your option) any later version. **
** **
** This program 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 General Public License for more details. **
** **
** You should have received a copy of the GNU General Public License **
** along with this program; if not, see <http://www.gnu.org/licenses/>. **
*************************************************************************/
#ifndef CALCULATOR_HPP
#define CALCULATOR_HPP
#include <istream>
#include <map>
#include <string>
#include "MessageException.hpp"
struct CalculatorException : public MessageException {
explicit CalculatorException (const std::string &msg) : MessageException(msg) {}
};
class Calculator {
public:
Calculator () : _numValue(0) {}
double eval (std::istream &is);
double eval (const std::string &expr);
void setVariable (const std::string &name, double value) {_variables[name] = value;}
double getVariable (const std::string &name) const;
protected:
double expr (std::istream &is, bool skip);
double term (std::istream &is, bool skip);
double prim (std::istream &is, bool skip);
char lex (std::istream &is);
char lookAhead (std::istream &is);
private:
std::map<std::string,double> _variables;
double _numValue;
std::string _strValue;
};
#endif
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