From a9abc1da41b56edbed00081800382e854d6698d0 Mon Sep 17 00:00:00 2001 From: Joe Zhao Date: Tue, 31 Mar 2015 23:41:55 +0800 Subject: rename to H**, +31 +32 +33 +34 +35 +36 --- H2.hs | 11 +++++++++++ 1 file changed, 11 insertions(+) create mode 100644 H2.hs (limited to 'H2.hs') diff --git a/H2.hs b/H2.hs new file mode 100644 index 0000000..60693ef --- /dev/null +++ b/H2.hs @@ -0,0 +1,11 @@ +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) -- cgit v1.2.3-70-g09d2