[phobos] Slices of ranges

[Simen Kjaeraas]

Lars Tandle Kyllingstad <lars at kyllingen.net> wrote:

> A while ago I fixed issue 5052, but doing so I unwittingly broke David's
> earlier fix for issue 4464.  I believe I have now fixed both issues (not
> committed to main Phobos repo yet):
>
> https://github.com/kyllingstad/phobos/commit/3948e3f61403bd7618913c36959158018970011d
>
> While fixing this, I noted that Take!R simply aliases to R when R is a
> type that supports slicing.  This assumes that the slice has the same
> type as the slicee(?), which doesn't have to be the case -- at least as
> far as the compiler or hasSlicing!() are concerned.
>
> It is easy to fix in Take, but I've now discovered that the same
> assumption is made in a lot of places: Retro, Stride, Chain... the list
> goes on.  Just do a search for hasSlicing, or look for things like
>
>     _input = _input[i .. j];
>
> Fixing it everywhere is likely to be a lot of work.  Do you think it is
> worth it, or is this a tiny corner case?

IMO, ranges that support slicing should return their own type as a slice. I
believe this is always the case in existing ranges, and that it's a good  
idea
in general.

-- 
Simen