FXExpression.h

/********************************************************************************
*                                                                               *
*                      E x p r e s s i o n   E v a l u a t o r                  *
*                                                                               *
*********************************************************************************
* Copyright (C) 1998,2026 by Jeroen van der Zijp.   All Rights Reserved.        *
*********************************************************************************
* 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 3 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.                           *
*                                                                               *
* You should have received a copy of the GNU Lesser General Public License      *
* along with this program.  If not, see <http://www.gnu.org/licenses/>          *
********************************************************************************/
#ifndef FXEXPRESSION_H
#define FXEXPRESSION_H

namespace FX {


class FXAPI FXExpression {
private:
  FXuchar *code;
private:
  static const FXuchar initial[];
  static const FXchar *const errors[];
public:

  enum Error {
    ErrOK,              
    ErrEmpty,           
    ErrMore,            
    ErrMemory,          
    ErrParent,          
    ErrToken,           
    ErrComma,           
    ErrIdent,           
    ErrColon,           
    ErrConst,           
    ErrLong             
    };

public:

  FXExpression();

  FXExpression(const FXExpression& orig);

  FXExpression(const FXchar* expression,const FXchar* variables=nullptr,Error* error=nullptr);

  FXExpression(const FXString& expression,const FXchar* variables=nullptr,Error* error=nullptr);

  FXExpression(const FXString& expression,const FXString& variables,Error* error=nullptr);

  FXExpression& operator=(const FXExpression& orig);

  FXbool empty() const { return (code==initial); }

  FXdouble evaluate(const FXdouble *args=nullptr) const;

  Error parse(const FXchar* expression,const FXchar* variables=nullptr);
  Error parse(const FXString& expression,const FXchar* variables=nullptr);
  Error parse(const FXString& expression,const FXString& variables);

  static const FXchar* getError(Error err){ return errors[err]; }

  friend FXAPI FXStream& operator<<(FXStream& store,const FXExpression& s);
  friend FXAPI FXStream& operator>>(FXStream& store,FXExpression& s);

  void clear();

 ~FXExpression();
  };


// Serialization
extern FXAPI FXStream& operator<<(FXStream& store,const FXExpression& s);
extern FXAPI FXStream& operator>>(FXStream& store,FXExpression& s);

}

#endif