[Haskell-cafe] A special function

Andrew Coppin andrewcoppin at btinternet.com
Sat May 19 16:13:39 EDT 2007


I'd like to share something with you. I call it "the evil ******* 
function from hell":

(Results xss) >>= f = Results $ map concat $ diagonalise $ map (foldr 
longZip [] . map (unpack . f)) xss

If you attempt to comprehend how this function works, you WILL in fact 
loose your mind! However, it does in fact work completely correctly. 
It's just not possible to know why. :-D

newtype Results t = Results [[t]]

unpack (Results xss) = xss

longZip = similar to zip (++)

diagonalise = transform an infinite list of infinite lists into an 
infinite list of finite lists.



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