Missing functions: foldr, reverse

[rohieb]

I'm trying to reduce an array right-to-left. In Haskell, I would use foldr for that, but that's missing in luafun. Alternatively, one could build it by applying foldl to a reversed array, but the reverse function is also missing. I think both functions should be present in a good functional library.

[rtsisyk]

Hi, I don't know how to implement foldr on iterators (which are left to right directed).

[HeinrichHartmann]

Indeed, reversal of iterators is not possible, cf. infinite case.

You can however, create an iterator from a table, that traverses in reverse order. Cf. #27