I'm afraid I haven't got the hang of match_partial.
Below is a little code with two functions that I think should produce
identical results, but don't.
In strip_commas_try1 I use:
boost::regex const front("^( *[[],*)(.*)$");
regex_match(it, end, what, front);
In strip_commas_try2 I use:
boost::regex const front("^( *[[],*)");
regex_match(it, end, what, front, boost::match_partial);
Why does this second case not result in
what[0].matched
?
Many thanks,
Angus
(This is with BOOST_VERSION 103002 and
g++ (GCC) 3.2 20020903 (Red Hat Linux 8.0 3.2-7)).
#include<iostream>
#include<string>
#include
using std::string;
string const strip_commas_try1(string const & input)
{
string::const_iterator it = input.begin();
string::const_iterator end = input.end();
// Strip any commas that follow immediately after the '['.
// "[,,,,foo..." -> "foo..."
boost::regex const front("^( *[[],*)(.*)$");
boost::smatch what;
regex_match(it, end, what, front);
if (!what[0].matched) {
std::cout << "Try 1 failed" << std::endl;
return string();
}
it = what[1].second;
string const result = string(it, end);
std::cout << "Try 1: " << result << std::endl;
return result;
}
string const strip_commas_try2(string const & input)
{
string::const_iterator it = input.begin();
string::const_iterator end = input.end();
// Strip any commas that follow immediately after the '['.
// "[,,,,foo..." -> "foo..."
boost::regex const front("^( *[[],*)");
boost::smatch what;
regex_match(it, end, what, front, boost::match_partial);
if (!what[0].matched) {
std::cout << "Try 2 failed" << '\n';
return string();
}
it = what[1].second;
string const result = string(it, end);
std::cout << "Try 1: " << result << std::endl;
return result;
}
int main()
{
string const input = "[,,,foo,,,,bar,,,gaz,,]";
std::cout << "Input: " << input << std::endl;
strip_commas_try1(input);
strip_commas_try2(input);
return 0;
}
