Turn function into infinite range

[monarch_dodra via Digitalmars-d-learn]

On Monday, 29 September 2014 at 17:02:43 UTC, Martin Nowak wrote:
> I though I've seen this around somewhere but can no longer find 
> it.

AFAIK, this as never existed.

We recently merged in "cache" into phobos. This seems like a 
prime candidate to expand to also take a function/delegate, as on 
of its built-in feature is that the value of "front" is not 
changed until "popFront()" is called. Having it also accept a 
function/delegate would make sense.

The issue with *not* having that is that a "dumb" adapter would 
fail the:
r.front == r.front
Test. And I'm pretty sure this test is expected to pass, even for 
the so called "transient" ranges.

I think I'll get to it now (this week).

Thoughts?