Proposal: Hide the int in opApply from the user

[bearophile]

bearophile:
> I don't know if D may use some standard way (like opApply) to allow
> parallel lazy scans (that is to manage the yield like Python does).

D 2.x has full closures too, so to solve those problems it may be used one of the full functional approaches discussed in the article too (I presume they aren't much used yet among D programmers).

Bye,
bearophile