ICFP '07 Post-Mortem: II

Next up are some helper datatypes to make our code look more like the spec. If you're familiar with the contest (which is what I'm assuming) nothing here should look strange. For those of you that aren't familiar with the contest, here's the specification (PDF).

• Part I
• Part II
• Part III
• Part IV

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DNA.lhs

> module DNA where

> import Data.List

> type DNA = String
> type RNA = [DNA]

> subseq' a = genericDrop a

> subseq a b = genericTake (b-a) . genericDrop a

> (!!!) :: [a] -> Int -> Maybe a
> dna !!! x = if x >= length dna then Nothing else Just (dna !! x)