On Wed, Feb 18, 2009 at 11:40, Christian Holmquist <c.holmquist@gmail.com> wrote:
Isn't it so that string to_string(T const&, Format) is about string generation, such as Spirit::Karma and boost::optional<T> from_string<T>(String) is about parsing, such as Spirit::Qi. and StringT convert_string<StringT>(String) about character conversion.
Well said.
boost::to_string/boost::from_string would be very useful if made right, but seems this discussion is mostly about nifty expressions such as convert("5").to<int>(), which is close to unusable to me. How would the following trivial case be written? vector<int> v; std::vector<std::string> s; std::transform(v.begin(), v.end(), boost::bind(convert, _1, ????), std::back_inserter(s));
I was worried it was too cute, and that's a great example why. That said, for specialization reasons it may well just be a wrapper around a converter<From, To> class that'd make a great functor. I'm glad to see a use case that actually has context, though. All the rest have just been syntax examples, as you mention.
I've not seen much discussions on how to provide formatters, or how to extend with user-defined types. Isn't that important for such a library?
I think it should be. I'd say the base specification is essential for integral <-> string conversions. The main thrust of this particular library has been getting rid of the default-constructability requirement and providing an interface that allows failure without throwing, though.