Forward ranges in Phobos v2

[Alexandru Ermicioi]

On Monday, 1 November 2021 at 23:46:07 UTC, H. S. Teoh wrote:
> Good question, ask Andrei. ;-)

Well, I hope he will check this thread and comment on it.

> Presumably, if we standardize on structs/classes, it could be 
> as simple as:
>
> 	auto myFunc(R)(R range) if (is(R == struct)) {
> 		... // forward range
> 	}
>
> 	auto myFunc(R)(R range) if (is(R == class)) {
> 		... // input range
> 	}
>
> But given that Andrei thinks it's a mistake for ranges to be 
> implemented as classes, I've no idea.

That would work, if you have templated funcs, but what if you 
need it in an interface?

If class based ranges are to be in D language, I doubt it will be 
possible to avoid .save function completely. At least for range 
interfaces, the save of forward range will have to be expressed 
through a method, such as .save.