ESLA

Embeddable Scriting LAnguage

frantz@pangea.stanford.edu

Stanford University, Rock Fracture Project research group

© 2003

Parser< T > Class Template Reference

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Detailed Description

template<class T>
class Parser< T >

Allow evaluation of complex string expressions

Author:

Frantz Maerten

Version:

1.0 BETA TEST for Dustin Lister

Example:

 Parser<double> p;
 string fct = "PI + ln(x+y^2.34)";
 


 // all the variables are automatically pre-registered !!
 p.set_function(fct); 
 p.set_var("x", 2.4538);
 p.set_var("y", 3.45e-12);
 


 // Evaluate the expression
 // -----------------------
 cout << p.get_function() << " = "
      << p.evaluate() << endl
      << "with:" << endl;
 


 // Display every registered variables with there value
 // ---------------------------------------------------
 for(
   Parser<double>::iterator it = p.begin();
   it != p.end();
   it++
 ) {
      cout << "  "  << (*it).first 
           << " = " << (*it).second << endl;
   }
 

Definition at line 81 of file fct_parser.h.

Public Types
typedef std::map< std::string, T >::iterator	iterator
Public Methods
	Parser ()
bool	set_function (const std::string &s, bool pre_test=true)
std::string	get_function ()
void	add_var (const std::string &s, T p=0)
void	set_var (const std::string &s, T p)
T	get_var (const std::string &s) const
T	evaluate ()
const std::string &	get_errors () const
void	flush ()
iterator	begin ()
iterator	end ()

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Member Typedef Documentation

template<class T> typedef std::map<std::string,T>::iterator Parser< T >::iterator

Definition at line 83 of file fct_parser.h. Referenced by Parser< T >::begin(), and Parser< T >::end().

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Constructor & Destructor Documentation

template<class T> Parser< T >::Parser (    )

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Member Function Documentation

template<class T> void Parser< T >::add_var (  const std::string &    s, T    p = 0 )

Add a variable within the parser. Parameters: s  the variable name p  the value (default 0) Definition at line 199 of file fct_parser.h.

template<class T> iterator Parser< T >::begin (    )

Return the begin iterator over all registered variable. The iterator has two menbers: "first" which is the name of the variable , and "second" which is the value of the variable. Definition at line 142 of file fct_parser.h. References Parser< T >::iterator.

template<class T> iterator Parser< T >::end (    )

Return the end iterator over all registered variable. See also: begin Definition at line 147 of file fct_parser.h. References Parser< T >::iterator.

template<class T> T Parser< T >::evaluate (    )

Evaluate the expression and return the result. Definition at line 232 of file fct_parser.h. Referenced by Parser< T >::set_function().

template<class T> void Parser< T >::flush (    )

Clear every registered variables and set the function to nothing

template<class T> const std::string& Parser< T >::get_errors (    )  const

Get a list of errors in string format, if any. Definition at line 130 of file fct_parser.h.

template<class T> std::string Parser< T >::get_function (    )

Return the function definition Definition at line 194 of file fct_parser.h.

template<class T> T Parser< T >::get_var (  const std::string &    s )  const

Get the value of a registered variable Parameters: s  the variable name Returns: the value Definition at line 212 of file fct_parser.h.

template<class T> bool Parser< T >::set_function (  const std::string &    s, bool    pre_test = true )

Set the function string to evaluate. Parameters: s  the string function pre_test  if you want to automatically registered variables from the expression, and test the validity of the expression. Returns: true if there's no errors. See also get_errors method to retrieve all reported errors. Definition at line 222 of file fct_parser.h. References Parser< T >::evaluate().

template<class T> void Parser< T >::set_var (  const std::string &    s, T    p )

Set a variable value. Parameters: s  the variable name p  the value Definition at line 204 of file fct_parser.h.

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