Nullable or Optional? Or something else?

[Andrei Alexandrescu]

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?


Andrei