simth::ParameterDescription::Parser Class Reference

#include <parameterdescription.h>

List of all members.

Public Member Functions
	Parser (const std::string &)
std::string	run ()
Static Public Member Functions
static std::string	parse (const std::string &)

---

Detailed Description

A simple arithmetic expression string parser, copied from the "desk calculator" example in Stroustrup's book, chapter 6.1. It accepts the following grammar:

program: END expression END

expression: expression + term expression - term term

term: term / primary term * primary primary

primary: NUMBER

• primary ( expression )

In other words, the operations +,-,*,/ are supported as well as parentheses for grouping. But as soon as a non-number character (i.e. arbitrary string) is found, the parsing is terminated and a simth::token_not_found exception is thrown.

---

Constructor & Destructor Documentation

simth::ParameterDescription::Parser::Parser (  const std::string &   )

Only store the string, don't do anything yet

---

Member Function Documentation

std::string simth::ParameterDescription::Parser::run (   )

Parse the string. This parser will only accept number expressions. As soon as a non-number character (i.e. arbitrary string) is found, the parsing is terminated and a simth::token_not_found exception is thrown.

static std::string simth::ParameterDescription::Parser::parse (  const std::string &   )  [static]

Driver for the parser. Returns a string with the evaluated arithmetic expression. If there are any non-number literals in the string, the parsing will be stopped and the input string will be returned unchanged.

---