Actually you can have more than one active iterator; however in that case, you should explicitly specify the iterating list when calling iter. I avoided the splice-based solution because I didn't want to add the overhead of copying the array. In truth, I'm not sure how much performance this buys me, considering all the splice-ish code which is now duplicated in perl. I also prefered not to take the OO aproach because I wanted a function that would feel more like a built-in (like each, for example).

That said, my solution is pretty ugly in comparison :)

update: After running some benchmarks, it's apparent that my solution is less efficient (by a factor of about 7x when iterating on each individual item), since the built-in splice is considerably faster than a re-implementation of a non-destructive splice in Perl. (though, my iter does outperform the OO iter when iterating and returning segments of length 100 or greater {really big grin})

So without further ado, -- this quote-unquote craft, and forget I ever wrote this piece of schnapz.

update2: Oh yeah, I forgot to mention, you wrote alot of code! :p

sub iter {
  my @a = @_;
  sub { splice @a, 0, shift || 1 };
}
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