Eric Niebler wrote:
Lynn Allan wrote:
The subsequent searches give valid information about the length and position, but other fields in the smatch:what variable seem invalid. regex_search( altDow.substr(32), what, rex) regex_search( altDow.substr(45), what, rex)
Watch out! altDow.substr(32) is returning a temporary string object. After regex_search returns, the temporary is destroyed and the results object is left holding iterators into a destroyed string.
Arggggg. Trying to get "up to speed" with Boost is probably a flawed thing to try to do at the same time as learning rudimentary aspects of STL. "We're not in MFC-land any more, Toto." <g> std::string altDow32 = altDow.substr(32); if( regex_search( altDow32, what, rex ) ) { unpack } The above (ugly) code clears up the "self inflicted wound". I'm "holding my nose" and using it to "unpack" the contents of the match_results variables. Thanks for the clarification.
Regardless, I'm unclear how to tell which of the "groups" of subexpressions was "hit". With boost::regex there was a way to loop thru the boolean field: what[i].matched and see what "hit", but I am not seeing a comparable accessor.
Xpressive is no different that Boost.Regex in this regard. what[i].matched is correct.
Works well. I think an earlier "trial and error stab at it" used what[i].matched() and back-tracked too far when the compiler complained. Your documentation is superior, but I've got a long ways to go to understand template notation adequately. Thanks again for your patience ....