----- Mensaje original ----- De: Edd Dawson <lists@mr-edd.co.uk> Fecha: Lunes, Enero 28, 2008 8:29 pm Asunto: Re: [boost] [review] Review of Flyweight library started January 21 and stillrunning! Para: boost@lists.boost.org
I have a situation where I'd like to experiment with this library, but I do not have time to start it yet. Perhaps my mentioning it is half-way valuable, though, so here goes :)
When I saw the announcement, I immediately thought about using the library to store and access Unicode text. Specifically, I am imagining that it might allow me to create a string type that acts as a randomly accessible sequence of glyphs. Each glyph would be a flyweight<>.
Most glyphs can of course be represented directly by a 32 bit integer, as they're only composed of a single code-point. However, uncommon glyphs that would need more than one code-point (because of combining marks) may benefit from a flyweight approach.
Is this a good use case? Would std::basic_string<flyweight<glyph> "work" (with appropriate character traits)? Could I also get boost's regular expressions to operate on these strings?
Hi Edd, I think you'd have problems making this work, but for reasons unrelated to flyweight: for std::basic_string<X> to work, char_traits<X> must have a nested ::int_type typedef with the property that X is convertible to that int_type and back to X without loss of information (http://tinyurl.com/2t3se7 ): If your glyphs contain more than two code-points you'd need an integral type longer than 64 bits, which is most likely unavailable, or else resort to some clever codification of sequences of code-points into 64 bits ints. Other than this, you can certainly use flyweight<> to store glyphs so as to achieve a uniform 32 bits per Unicode character. This can be all wrapped up by a string-like container class. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo