reduce

• Here's a fine, fine trick.

• Let's write a reduce call to ask if a list contains all positive numbers.

        reduce { $a && $b > 0 } "yes", @list;

• If you apply this to the list (0 .. 1000000), it goes all way to the end

• Solution:

        reduce { $a && $b > 0 || ($a=undef, last) } "yes", @list;

• last?!

• Yes! last is dynamically scoped!

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Copyright © 2003 M. J. Dominus