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import Data.List (tails)
suffixes :: [a] -> [[a]]
suffixes xs@(_:xs') = xs : suffixes xs'
-- as pattern.
-- binds xs to the value on the right of the @
suffixes _ = []
-- same thing without as-pattern
-- This will do a copy of the data, the as-pattern doesn't
suffixesNoAs (x:xs) = (x:xs) : suffixesNoAs xs
suffixesNoAs _ = []
-- even better
suffixes2 :: [a] -> [[a]]
suffixes2 xs = init (tails xs)
compose :: (b -> c) -> (a -> b) -> a -> c
compose f g x = f (g x)
suffixes3 xs = compose init tails xs
suffixes4 = compose init tails
-- no need to invent the compose function
suffixes5 = init . tails
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