your point about the range-computing subroutine being called only once when using a Perl-style foreach loop (as compared to the "equivalent" C-style loop) is very interesting.

I sometimes wondered, in similar cases, whether I should pre-compute the range limits in order to sort of cache them before entering the for loop, but never actually cared to check, now I know that, in such cases, Perl is actually doing the value caching for you. Good to know. Thank you, Athanasius.