I think the code should be:

/(bb|(?!bb)..)/
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Update:And I think the /(.{2})/ should be read "give me anything, but I want it twice!".

Jenda
Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live.
   -- Rick Osborne

Edit by castaway: Closed small tag in signature

But that's "To be or not be twice".

Right, I'd interpret that their specification was "Two 'b' or not two 'b'". In that case their code is wrong. For example, "ab" is not two 'b's, which means the second boolean condition evals to true (ie., it meets the specification). However, it does not match /(bb|[^b]{2})/, so the code is wrong.

And if they did, that can be shortened to: /(.{2})/

No, because that is highly political code. It says something without expressing any meaning, and is completely interchangeable for a lot of situations.

1
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-- Mike

--
just,my${.02}

------
We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.

Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.

Well, not. That would mean "to be at the beginning or not to be at the end". And the /(?!bb)$ would match anything. If you are at the very end of the string you may be sure there are not two more "b"s left. :-)

Jenda
Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live.
   -- Rick Osborne

Edit by castaway: Closed small tag in signature

Or you could do it conditionally. Prints either 2 B's or something that's not 2 B's.

#!/usr/local/bin/perl -l
 
foreach ('b', 'bb', 'B', 'foo', 'bar', 'BB') {
    print m/^b{2}$/i ? "\x42\x42" : bb(); 
}
sub bb() {
    while(1) { return chr(rand(100)) . chr(rand(100)) unless (m/^b{2}$
+/i); }
}
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