On 9/8/2011 5:09 PM, Jens Saathoff wrote:
Hi!
I'm playing a bit with boost::xpressive and have no clue how to get a 100,000 (comma as separator) to a double as 1000000.00 or 250,000.10 as a double 250000.10 or 12,00 as double 12.00 or 1,200,500.00 as double 1200500.00. I'm working with xpressive since a day. What's the regex for that?
And how can i use it in xpressive-grammar as a nested regex?
Example subject: "I payed 100,200.50 Dollar"
Example Regex on subject: 'I payed' >> (s1=getdoubleregex) >> ' Dollar'
Is it possible to do it like that? Set return-value/type in a regex?
Try something like the following: #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"; } } } -- Eric Niebler BoostPro Computing http://www.boostpro.com