I very enjoy playing with spirit, but I was looking for a 5-line code that only boost have the secret... Anyway, thank you ! 2010/11/30 Hartmut Kaiser

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Is there a simple math expression parser in boost ? I only need to parse those kind of expression: "1+2/3".

I believe Spirit is exactly what you're looking for. It has almost a dozen different calculator examples to choose from as a starting point for your needs.

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I have been thinking on boost::spirit, but it is quite hard for what I need.

Why?

Regards Hartmut --------------- http://boost-spirit.com

_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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...

Is there a simple math expression parser in boost ? I only need to parse those kind of expression: "1+2/3". I believe Spirit is exactly what you're looking for. It has almost a dozen different calculator examples to choose from as a starting point for your needs.

...

I have been thinking on boost::spirit, but it is quite hard for what I need. Why?

I very enjoy playing with spirit, but I was looking for a 5-line code that only boost have the secret...

Well, not exactly five lines, but here is a simple calculator grammar written in Spirit: namespace qi = boost::spirit::qi; template <typename Iterator> struct calculator : qi::grammar { calculator() : calculator::base_type(expression) { expression = term >> *( ('+' >> term) | ('-' >> term) ) ; term = factor >> *( ('*' >> factor) | ('/' >> factor) ) ; factor = qi::uint_ | '(' >> expression >> ')' | ('-' >> factor) | ('+' >> factor) ; } qi::rule expression, term, factor; }; And here is how to use it: std::string input("1+2/3"); calculatorstd::string::const_iterator calc; if (phrase_parse(input.begin(), input.end(), calc, qi::space)) std::cout << "successfully parsed: " << input << std::endl; Regards Hartmut --------------- http://boost-spirit.com

Sorry, but I meant that it has to compute the final result. What would you recommend to do that ? 2010/11/30 Eloi Du Bois

Wow ! Excellent :)

I thought it would be more verbose than that.

Thank you very much, Eloi Du Bois.

2010/11/30 Hartmut Kaiser

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...

...

...

Is there a simple math expression parser in boost ?

...

...

...

I only need to parse those kind of expression: "1+2/3". I believe Spirit is exactly what you're looking for. It has almost a dozen different calculator examples to choose from as a starting point for your needs.

...

I have been thinking on boost::spirit, but it is quite hard for what I need. Why?

I very enjoy playing with spirit, but I was looking for a 5-line code that only boost have the secret...

Well, not exactly five lines, but here is a simple calculator grammar written in Spirit:

namespace qi = boost::spirit::qi;

template <typename Iterator> struct calculator : qi::grammar { calculator() : calculator::base_type(expression) { expression = term >> *( ('+' >> term) | ('-' >> term) ) ; term = factor >> *( ('*' >> factor) | ('/' >> factor) ) ; factor = qi::uint_ | '(' >> expression >> ')' | ('-' >> factor) | ('+' >> factor) ; } qi::rule expression, term, factor; };

And here is how to use it:

std::string input("1+2/3"); calculatorstd::string::const_iterator calc; if (phrase_parse(input.begin(), input.end(), calc, qi::space)) std::cout << "successfully parsed: " << input << std::endl;

Regards Hartmut --------------- http://boost-spirit.com

_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

Ok, thank you for the link. 2010/11/30 Hartmut Kaiser

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Sorry, but I meant that it has to compute the final result. What would you recommend to do that ?

Why don't you look for yourself here: $BOOST_ROOT/libs/spirit/example/qi/calc3.cpp (or any of the more complex calculator examples)?

Regards Hartmut --------------- http://boost-spirit.com

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2010/11/30 Eloi Du Bois Wow ! Excellent :)

I thought it would be more verbose than that.

Thank you very much, Eloi Du Bois. 2010/11/30 Hartmut Kaiser

...

...

...

Is there a simple math expression parser in boost ?

...

...

...

I only need to parse those kind of expression: "1+2/3". I believe Spirit is exactly what you're looking for. It has almost a dozen different calculator examples to choose from as a starting point for your needs.

...

I have been thinking on boost::spirit, but it is quite hard for what I need. Why?

I very enjoy playing with spirit, but I was looking for a 5-line code that only boost have the secret... Well, not exactly five lines, but here is a simple calculator grammar written in Spirit:

namespace qi = boost::spirit::qi;

template <typename Iterator> struct calculator : qi::grammar { calculator() : calculator::base_type(expression) { expression = term >> *( ('+' >> term) | ('-' >> term) ) ; term = factor >> *( ('*' >> factor) | ('/' >> factor) ) ; factor = qi::uint_ | '(' >> expression >> ')' | ('-' >> factor) | ('+' >> factor) ; } qi::rule expression, term, factor; };

And here is how to use it:

std::string input("1+2/3"); calculatorstd::string::const_iterator calc; if (phrase_parse(input.begin(), input.end(), calc, qi::space)) std::cout << "successfully parsed: " << input << std::endl;

Regards Hartmut --------------- http://boost-spirit.com

_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users