From slices to perfect imitators: opByValue

[Timon Gehr via Digitalmars-d]

On 05/08/2014 12:14 PM, Michel Fortin wrote:
>
> Will this solve the problem that const(MyRange!(const T)) is a different
> type from const(MyRange!(T))?

No, but as stated it aggravates this problem.

> I doubt it. But they should be the same
> type if we want to follow the semantics of the language's slices, where
> const(const(T)[]) is the same as const(T[]).
>
> Perhaps this is an orthogonal issue,  but I wonder whether a solution to
> the above problem could make opByValue unnecessary.

Not necessarily automatically, because there would still need to be a 
way to figure out that actually const(S!T) -> S!(const(T)) is the way to 
remove top-level constness. (Because sometimes it is actually 
const(S!(T[])) -> S!(const(T)[]), for example, for most ranges in 
std.algorithm.)

But I think the above problem is the fundamental one.