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";
> }
> }
> }
>