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
#include
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
