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author | Joe Zhao <ztuowen@gmail.com> | 2015-01-29 16:29:05 +0800 |
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committer | Joe Zhao <ztuowen@gmail.com> | 2015-01-29 16:29:05 +0800 |
commit | 0135b3ac0d41dda2a4c210e7c3989f20b672be5d (patch) | |
tree | 7284971efac168e9c704ec74e50cf4ce66df6916 /p2.hs | |
parent | edcc6ba8ca9d6b883b59548eb8bb5e312c73f43b (diff) | |
download | h99-0135b3ac0d41dda2a4c210e7c3989f20b672be5d.tar.gz h99-0135b3ac0d41dda2a4c210e7c3989f20b672be5d.tar.bz2 h99-0135b3ac0d41dda2a4c210e7c3989f20b672be5d.zip |
p1+ p2
Diffstat (limited to 'p2.hs')
-rw-r--r-- | p2.hs | 11 |
1 files changed, 11 insertions, 0 deletions
@@ -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) |