Michael Coles, MCDBA wrote:

I'm taking a look at http://www.boost.org/libs/regex/doc/captures.html but I'm not seeing how to access the capture start location with match_extra? I'll keep digging but if anyone out there knows of a shortcut to the answer, it'd be appreciated.

<alert comment="boost newbie"> Here's some code adapted from the regex chapter in: "Beyond the C++ Standard Library ... an Introduction to Boost: #include <iostream> #include class regex_callback { private: int sum_; public: regex_callback() : sum_(0) {} template <typename T> void operator() (const T& what) { sum_ += atoi(what[1].str().c_str()); std::cout << "Position: " << what.position(1) << " Length: " << what.length(1) << std::endl; } int sum() const { return sum_; } }; int main(int argc, char** argv) { boost::regex reg("(\\d+),?"); std::string s="1,1,2,3,5,8,13,21"; boost::sregex_iterator it(s.begin(), s.end(), reg); boost::sregex_iterator end; regex_callback c; int sum = for_each(it, end, c).sum(); std::cout << "Sum: " << sum << std::endl; return 0; } </alert>

-----Original Message----- From: boost-users-bounces@lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Lynn Allan Sent: Friday, April 07, 2006 6:04 PM To: boost-users@lists.boost.org Subject: Re: [Boost-users] Regex Submatch Position Question

If I understand your question, the snippet sample code related to "Captures"

can be adapted: http://www.boost.org/libs/regex/doc/captures.html

HTH

----- Original Message ----- From: Newsgroups: gmane.comp.lib.boost.user Sent: Friday, April 07, 2006 12:19 PM Subject: Regex Submatch Position Question

...

Hi all,

Quick question about the Boost::Regex library. Is there a way to identify, with sub-matches, where a match in the search string is made and the length of the match? For instance, with the following regular expression and search string:

Regex ==> "(\d+)" Search String ==> "Give me 100 dollars or give me 2001 dollars."

Is there a way to determine that the subexpression matched at positions 8 and 31 in the search string, and that the lengths of the matches were three and four characters?

Thanks

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<snip>

...

Regex ==> "(\d+)" Search String ==> "Give me 100 dollars or give me 2001 dollars."

Is there a way to determine that the subexpression matched at positions 8 and 31 in the search string, and that the lengths of the matches were three and four characters? </snip>

Take a look at the position(sub) and length(sub) member functions of match_results<>

sub_match also has a length() member function, but no position() because it doesn't know where the search started from (unlike match_results which does).

There's no need to get involved with repeated captures and match_extra etc BTW.

John.

Thank you, I think that's exactly what I need. Appreciate it!