[Boost-users] boost::regex: regex meta data or AST for regex?

in concrete: Is it possible to not only get the #no of groups (sub-expressions) via basic_regex::mark_count(), but also their position (begin() / end() iterators) in the given regex string (c'tor argument)? more general: Can an AST be created for a the given regex string (c'tor argument)? E.g with boost::spirit?