Evaluator.h

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// -*- C++ -*-
// $Id:$
// ---------------------------------------------------------------------------

#ifndef HEP_EVALUATOR_H
#define HEP_EVALUATOR_H

#include <string>

namespace HepTool {

class Evaluator {
 public: 

  enum {
    OK,                         
    WARNING_EXISTING_VARIABLE,  
    WARNING_EXISTING_FUNCTION,  
    WARNING_BLANK_STRING,       
    ERROR_NOT_A_NAME,           
    ERROR_SYNTAX_ERROR,         
    ERROR_UNPAIRED_PARENTHESIS, 
    ERROR_UNEXPECTED_SYMBOL,    
    ERROR_UNKNOWN_VARIABLE,     
    ERROR_UNKNOWN_FUNCTION,     
    ERROR_EMPTY_PARAMETER,      
    ERROR_CALCULATION_ERROR     
  };

  Evaluator();

  ~Evaluator(); 

  double evaluate(const char * expression);

  int status() const;

  int error_position() const; 

  void print_error() const;
  std::string error_name() const;

  void setVariable(const char * name, double value);

  void setVariable(const char * name, const char * expression);

  void setFunction(const char * name, double (*fun)());

  void setFunction(const char * name, double (*fun)(double));

  void setFunction(const char * name, double (*fun)(double,double));

  void setFunction(const char * name, double (*fun)(double,double,double));

  void setFunction(const char * name,
           double (*fun)(double,double,double,double));

  void setFunction(const char * name,
                   double (*fun)(double,double,double,double,double));

  bool findVariable(const char * name) const;

  bool findFunction(const char * name, int npar) const;

  void removeVariable(const char * name);

  void removeFunction(const char * name, int npar);

  void clear();

  void setStdMath();

  void setSystemOfUnits(double meter    = 1.0,
                        double kilogram = 1.0,
                        double second   = 1.0,
                        double ampere   = 1.0,
                        double kelvin   = 1.0,
                        double mole     = 1.0,
                        double candela  = 1.0);

private: 
  void * p;                                 // private data 
  Evaluator(const Evaluator &);             // copy constructor is not allowed
  Evaluator & operator=(const Evaluator &); // assignment is not allowed
};

} // namespace HepTool

#endif /* HEP_EVALUATOR_H */