TOOL

#ifndef VM_CALC_EXPRESSION_ANALYZER_H_INCLUDED
#define VM_CALC_EXPRESSION_ANALYZER_H_INCLUDED
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/*
       $Archive:   $

      $Revision:   $
          $Date:   $
        $Author:   $

    Description:   Declaration of the main aggregate class for expression
                   analysis and calculation

                      TOOL And XML FORMS License
                      ==========================

                      Except where otherwise noted, all of the documentation 
                      and software included in the TOOL package is 
                      copyrighted by Michael Swartzendruber.

                      Copyright (C) 2005 Michael John Swartzendruber. 
                      All rights reserved.

                      Access to this code, whether intentional or accidental,
                      does NOT IMPLY any transfer of rights.

                      This software is provided "as-is," without any express 
                      or implied warranty. In no event shall the author be held
                      liable for any damages arising from the use of this software.

                      Permission is granted to anyone to use this software for 
                      any purpose, including commercial applications, and to 
                      alter and redistribute it, provided that the following 
                      conditions are met:

                      1. All redistributions of source code files must retain 
                         all copyright notices that are currently in place, 
                         and this list of conditions without modification.

                      2. The origin of this software must not be misrepresented;
                         you must not claim that you wrote the original software.

                      3. If you use this software in another product, an acknowledgment
                         in the product documentation would be appreciated but is
                         not required.

                      4. Modified versions in source or binary form must be plainly 
                         marked as such, and must not be misrepresented as being 
                         the original software.
*/
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#pragma warning ( disable : 4786 )
#include <map>
#include <string>
#include "VMCalcValueBase.h"


// Tree evaluation variables
//
#define DIVISION_BY_0        1
#define ILEGAL_OPERATION     2
#define UNDEFINED_VARIABLE   3
#define INVALID_DOMAIN       4


typedef std::map< std::string, VMCalcValueBase* > CMapVariable;
typedef CMapVariable::iterator                    IterCMapVariable;


class VMCalcExpressionAnalyzer 
{
public:
  VMCalcExpressionAnalyzer( void );
  VMCalcExpressionAnalyzer( CMapVariable* poVarsMap );
  VMCalcExpressionAnalyzer( VMCalcExpressionAnalyzer& roOther );
  virtual ~VMCalcExpressionAnalyzer( void );

  VMCalcExpressionAnalyzer& operator=( VMCalcExpressionAnalyzer& roOther );
  void AtachVariables( CMapVariable* poVarsMap );
	
  typedef struct TagNode 
  {
    TagNode* m_pxLeft;
    TagNode* m_pxRight;

    unsigned char m_ucOperation; 
    union 
    { 
      double       m_dValue;
      std::string* m_oValueString;
    };
  } NODE, *PNODE;
	
  PNODE CloneTree( void );
  int   UpdateValue( void );
  PNODE GetExpressionRoot( void );
  int   Value( double& rdOutput );
  int   ChangeExpression( const char* roNewExpression );

  std::string GetEquation( void ) { return( m_oEquation ); };

private:
  PNODE PerformSignedOperation( void );
  PNODE PerformLogicalOperation( void );
  void  SkipSpaces( void );

  CMapVariable*   m_poVariables;     // pointer to value table
  std::string     m_oEquation;       // the expression in string
  int             m_iPosition;       // string parsing variable
  PNODE           m_xExpressionTree; // the expresion as a binary tree
	
  double EvaluateExpression( PNODE pxRoot );
  PNODE  FactorExpression( void );  // the partial expresion parsing functions
  PNODE  FactorString( void );
  PNODE  Compute( void );
  PNODE  FactorMultDiv( void );
  PNODE  FactorSumDiff( void );
  void   PruneTree( PNODE pxRoot );
  PNODE  CloneTree( PNODE pxRoot );
};


#endif


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