David Abrahams wrote:
Joel de Guzman <joel@boost-consulting.com> writes:
There's also an interesting use-case that became apparent recently: making arbitrary structs/classes conforming sequences easily-- as easy as providing a single function. Pardon me if this is rather sketchy at this point, but imagine being able to write:
Our user defined struct:
struct point { float x, float y; };
Customization:
fusion::map<keys::x_, keys::y_, float&, float&> as_fusion_sequence(point& p) { return fusion::map_tie<keys::x_, keys::y_>(p.x, p.y); }
Use:
point p = { 123.456, 789.012 }; fusion::for_each(p, std::cout << _1 << std::endl);
That's nice, but I don't think it's really the same thing. Doesn't it incur an extra level of indirection?
Not the same as what? Sorry, I think I missed something in your question/comment. Cheers, -- Joel de Guzman http://www.boost-consulting.com http://spirit.sf.net