Re: [Boost-users] boost::xpressive : Get thousand separator as double

Subject: Re: [Boost-users] boost::xpressive : Get thousand separator as double
From: Jens Saathoff (jensesaat_at_[hidden])
Date: 2011-09-09 05:26:58

Perfect! That works!

I will compare it with my thousand-sep rule/grammar in boost::spirit, a
little benchmark to find out which one is faster. Do have
experiences/results with boost::spirit vs. boost::xpressive?

Thank you very much. Have a nice weekend.

2011/9/9 Eric Niebler <eric_at_[hidden]>

> #include <string>
> #include <iostream>
> #include <iomanip>
> #include <boost/xpressive/xpressive_static.hpp>
> #include <boost/xpressive/regex_actions.hpp>
> namespace xp = boost::xpressive;
>
> int main()
> {
>    using namespace xp;
>    placeholder<double> result;
>    sregex double_ = ~after(_d) >>
>        // a number with no group separators, and either a period or comma
>        // for fraction separator
>        (+_d)[result = as<double>(_)] >>
>            !((set=',','.') >> (_d >> _d)[result += as<int>(_)/100.0]) >>
>            ~before(set[_d|','|'.'])
>        // A number with optional group separators
>      | repeat<1,3>(_d)[result = as<int>(_)] >>
>        (
>            // ... with comma group separators and period fraction separator
>            *(',' >> repeat<3>(_d)[result *= 1000, result += as<int>(_)]) >>
>                !('.' >> (_d >> _d)[result += as<int>(_)/100.0]) >>
>                ~before(set[_d|','|'.'])
>            // ... with period group separators and comma fraction separator
>          | *('.' >> repeat<3>(_d)[result *= 1000, result += as<int>(_)]) >>
>                !(',' >> (_d >> _d)[result += as<int>(_)/100.0]) >>
>                ~before(set[_d|','|'.'])
>        );
>
>    std::string str;
>    double d = 0.0;
>    smatch what;
>    what.let(result = d);
>    std::cout << std::fixed << std::setprecision(2);
>    while (std::getline(std::cin, str))
>    {
>        if (regex_search(str, what, double_))
>        {
>            std::cout << "Double = " << d << '\n';
>        }
>        else
>        {
>            std::cout << "No match\n";
>        }
>    }
> }
>