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authorJoe Zhao <ztuowen@gmail.com>2015-03-31 23:41:55 +0800
committerJoe Zhao <ztuowen@gmail.com>2015-03-31 23:41:55 +0800
commita9abc1da41b56edbed00081800382e854d6698d0 (patch)
tree5265cc1c5296768438b67299afd59bcc57c58f0c /H2.hs
parent378f6303e8860b7bbca7dea787d584a6728cebf1 (diff)
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rename to H**, +31 +32 +33 +34 +35 +36
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+import Data.Foldable as F
+
+myButLast :: Foldable f => f a -> a
+
+myButLast = fst . F.foldl (\(a,b) x -> (b,x)) (err1, err2)
+ where
+ err1 = error "Empty list"
+ err2 = error "Not enough elements"
+
+mySafeButLast :: Foldable f => f a -> Maybe a
+mySafeButLast = fst . F.foldl (\(a,b) x -> (b,Just x)) (Nothing, Nothing)