Why not allow to convert between different string types?
Yes, I believe that is a very sensible question. In fact, I've tightened up the type checks for the implemented boost::string::convert() to minimize possible signature clashes with/of further extensions (via specializations/oveloads).
In the current form boost::string::convert() is essentially a replacement for lexical_cast with added forrmatting, locale, etc. support. To add, say, u8string<->wstring conversion support we'll need overloads
std::wstring convert(std::u8string) std::u8string convert(std::wstring)
added.
Makes sense.
Possible applications:
- std::string <--> std::wstring or similar (based on a future Boost.Unicode library)
I am not sure we can do std::string <-> std::wstring unless we know what std::string represents (currently it can be UTF8 or MBCS). If, with the introduction of std::u8string, std::string is guaranteed to be MBCS, then I guess we can have std::string <-> std::wstring as well.
That's what I meant. Sorry for being in-concise.
- conversion between different symbol (character) sets
Currently convert() heavily relies on supplied types. Are we going to have distinct types for different symbol (character) sets? If not, then we might move forward as I've done for the throwing behavior (i.e. run-time configuration vs. compile-time configuration):
int i = boost::string::convert(str, -1) >> boost::throw_t();
to pass a clue/directive what to do. Similarly we might do
string new_set_str = boost::string::convert(old_set_str) >> new_set_directive();
Just thinking out loud. Does it look anywhere close to what you had in mind?
In Spirit we use a using namespace boost::spirit::ascii; (or similar) to tie in a specific character set. I'm not sure if this is a viable solution for you. Regards Hartmut