In Python I would have told you to use a generator, with the yield statement (which allows to interrupt the execution of a function to yield a value, and resume the execution later) :).

As far as I could tell though, it looks like grep might just do what you want, although it doesn't have the "evaluation-laziness" of yield. grep will allow you to extract the elements that match a condition from a list:

my @list = 1..10;
my @odd = grep { $_ % 2 } @list;
# Now you can work on the elements of @odd one element at a time, by r
+emoving them as you use them if you want.
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