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FXExpression.h

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00001 /********************************************************************************
00002 *                                                                               *
00003 *                      E x p r e s s i o n   E v a l u a t o r                  *
00004 *                                                                               *
00005 *********************************************************************************
00006 * Copyright (C) 1998,2009 by Jeroen van der Zijp.   All Rights Reserved.        *
00007 *********************************************************************************
00008 * This library is free software; you can redistribute it and/or modify          *
00009 * it under the terms of the GNU Lesser General Public License as published by   *
00010 * the Free Software Foundation; either version 3 of the License, or             *
00011 * (at your option) any later version.                                           *
00012 *                                                                               *
00013 * This library is distributed in the hope that it will be useful,               *
00014 * but WITHOUT ANY WARRANTY; without even the implied warranty of                *
00015 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                 *
00016 * GNU Lesser General Public License for more details.                           *
00017 *                                                                               *
00018 * You should have received a copy of the GNU Lesser General Public License      *
00019 * along with this program.  If not, see <http://www.gnu.org/licenses/>          *
00020 *********************************************************************************
00021 * $Id: FXExpression.h,v 1.18 2009/01/06 13:07:23 fox Exp $                      *
00022 ********************************************************************************/
00023 #ifndef FXEXPRESSION_H
00024 #define FXEXPRESSION_H
00025 
00026 
00027 namespace FX {
00028 
00029 
00030 /// Expression error codes
00031 enum FXExpressionError {
00032   EXPRERR_OK,
00033   EXPRERR_EMPTY,             /// Empty input
00034   EXPRERR_MEMORY,            /// Out of memory
00035   EXPRERR_PAREN,             /// Unmatched parentheses
00036   EXPRERR_TOKEN,             /// Illegal token
00037   EXPRERR_COMMA,             /// Expected comma
00038   EXPRERR_IDENT              /// Unknown identifier
00039   };
00040 
00041 
00042 /// Expression
00043 class FXAPI FXExpression {
00044 private:
00045   FXuchar *code;
00046 private:
00047   static const FXuchar initial[];
00048   static const FXchar *const errors[];
00049 public:
00050 
00051   /// Construct empty expression object
00052   FXExpression();
00053 
00054   /// Copy expression object
00055   FXExpression(const FXExpression& orig);
00056 
00057   /// Compile expression; if error is not NULL, error code is returned
00058   FXExpression(const FXchar* expression,const FXchar* variables=NULL,FXExpressionError* error=NULL);
00059 
00060   /// Compile expression; if error is not NULL, error code is returned
00061   FXExpression(const FXString& expression,const FXString& variables=FXString::null,FXExpressionError* error=NULL);
00062 
00063   /// Assign another expression to this one
00064   FXExpression& operator=(const FXExpression& orig);
00065 
00066   /// See if expression is empty
00067   FXbool empty() const { return (code==initial); }
00068 
00069   /// Evaluate expression with given arguments, if any
00070   FXdouble evaluate(const FXdouble *args=NULL);
00071 
00072   /// Parse expression, return error code if syntax error is found
00073   FXExpressionError parse(const FXchar* expression,const FXchar* variables=NULL);
00074 
00075   /// Parse expression, return error code if syntax error is found
00076   FXExpressionError parse(const FXString& expression,const FXString& variables=FXString::null);
00077 
00078   /// Returns error code for given error
00079   static const FXchar* getError(FXExpressionError err){ return errors[err]; }
00080 
00081   /// Delete
00082  ~FXExpression();
00083   };
00084 
00085 }
00086 
00087 #endif

Copyright © 1997-2009 Jeroen van der Zijp