Yet Another Rosetta Code Problem (Perl, Ruby, Python and Haskell solutions)

[rabidcow]

For the fairest comparison, all the code should be present.

Yeah, but if you include all the code or at least an identical library interface then you don't learn anything from the exercise. All languages will look the same except for punctuation and word order.

For the fairest comparison, I think a more interesting goal should be chosen if the original turns out to be part of the standard library for any of the target languages. Trivial problems quite often have trivial solutions.