I caught the tail end of a discussion on irc.freenode.net's #perl channel about how to split a string into equal-sized chunks. Some people were trying to use split() to accomplish this; one person fell prey to this: 
my $string = "abcdefghi";
my @fields = split /(?=.{3})/, $string;

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They expected this to mean "split $string at every location that is followed by three characters (and then skip ahead three characters!)", but what it really means is "split $string at every location that is followed by three characters". They ended up getting ("a", "b", "c", "d", "e", "f", "ghi").

So how can you use split() to do this? Someone said "Couldn't you abuse \G?", and that reminded me of the internal assignment to $_ of the string being matched against, and the resulting use of pos()! I present: 

my @fields = split /(?(?{pos() % 3})(?!))/, $string;

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Update: Yes, I know about unpack(), etc. This was merely presented as the most direct way to accomplish the task using split().

Jeff japhy Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and perl hacker
How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart

In reply to Using split() to divide a string by length by japhy

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