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wangbj/viewPatterns1.hs

Created January 14, 2016 19:07
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GHC ViewPatterns.
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viewPatterns1.hs
{-# LANGUAGE ViewPatterns #-}
import qualified Data.Sequence as Seq
import Data.Sequence(Seq)
lastr :: Seq a -> Maybe a
lastr (Seq.viewr -> Seq.EmptyR) = Nothing
lastr (Seq.viewr -> s Seq.:> x) = Just x
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