Fernando Cacciola wrote:
(and please!, this doesn't mean at all that optional is a pointer... both optional<> and pointers are models of a more fundamental concept: OptionalPointee or Nullable)
I dislike the term OptionalPointee as it names the concept after a possible implementation <g> I DO like the term Nullable while the debate remains open ;?) Putting aside rebinding for now, one reason I would really like an optional type would be to divorce Nullability from pointer semantics. One reason pointers make bad Nullable types is that they reserve a value from the valid range to represent their null value. The whole reason to use optional< int > is to avoid that very problem. Consider: int * px = 0; optional< int * > ox1; optional< int * > ox2 = px; Is ox2 an optional value bound to a nulled value, or just a null value? How is it different to ox1, an unbound null value? int x = 1; int *px = &x; optional< int * > ox = px; *ox == 1? or *ox == px? There is no reason for these questions to confuse clear minds on a bright day, but removing the pointer interface could be clearer on the muggy midsummer days when you are trying to get the code out before a deadline... -- AlisdairM