Nullable or Optional? Or something else?

[Leandro Lucarella]

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/
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