propellor/src/Utility/Data.hs

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{- utilities for simple data types
-
2014-11-22 02:26:39 +00:00
- Copyright 2013 Joey Hess <id@joeyh.name>
-
2014-05-10 14:05:28 +00:00
- License: BSD-2-clause
-}
module Utility.Data where
{- First item in the list that is not Nothing. -}
firstJust :: Eq a => [Maybe a] -> Maybe a
firstJust ms = case dropWhile (== Nothing) ms of
[] -> Nothing
(md:_) -> md
eitherToMaybe :: Either a b -> Maybe b
eitherToMaybe = either (const Nothing) Just