Andrei Alexandrescu, el 3 de septiembre a las 10:34 me escribiste: > Leandro Lucarella wrote: > >Andrei Alexandrescu, el 2 de septiembre a las 14:39 me escribiste: > >>I plan to add a Nullable struct to Phobos (akin to C#'s Nullable, Boost's > >>Optional). > >> > >>Apparently a good design is to define Optional!T with a minimum of member > >>functions (ideally none) and have it use the "alias this" feature to > >>masquerade as > >>a T. That way Optional!T looks and feels much like a T, except that it > >>supports a function > >> > >>bool isNull(T)(Optional!T value); > >> > >>Am I on the right track? If so, what is the name you'd prefer for this > >>artifact? > >Maybe this is a very silly question, but what is exactly the difference > >between Optional!T o/isNull(o) and T* o/o is null? > > It's a good question. There are two differences: (a) Optional!T behaves > almost like a T in expressions, and (b) Optional!T does not support most > features of pointers, such as arithmetic and comparison.
(a) And *o behaves *exactly* like T, that doesn't seems like an advantage So, judging for (b) I guess is just a safety meassure. I agree with some other mail in this thread that it would be better to have proper references if you don't want to allow pointer arithmetics... -- Leandro Lucarella (luca) | Blog colectivo: http://www.mazziblog.com.ar/blog/ ---------------------------------------------------------------------------- GPG Key: 5F5A8D05 (F8CD F9A7 BF00 5431 4145 104C 949E BFB6 5F5A 8D05) ---------------------------------------------------------------------------- Hey you, dont help them to bury the light Don't give in without a fight.
