That's fantastic, thank you. I have an unrelated Boost.Regex question: how expensive are basic_regex objects to copy? Say, relative to constructing (and thus reparsing) from a string pattern, anew?
A *lot* more efficient - basic_regex is a pimpl so it's just a shared_ptr copy to copy a basic_regex.
The reason I ask is because I have a variant type with several value types, including a regex type. I was wondering whether it makes more sense to store the regex pattern in that variant as a string, and to construct the actual basic_regex from that string every time I need to operate on it, or to store it as a basic_regex and hope that copies are not too expensive. One other alternative is to store the regex on the heap using a smart pointer, but I'd rather keep value semantics so long as performance isn't an issue.
No, don't construct every time you need it, that's just wasting CPU cycles :-(
(Oh, incidentally, does Boost.Regex have support for Boost.Serialization? Right now what I do is serialize it [the pattern] as an std::string -- is that the recommended approach?)
Yes, there's no explicit serialization support. HTH, John.