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authorJoey Hess2014-03-29 23:10:52 -0400
committerJoey Hess2014-03-29 23:16:43 -0400
commitd9af8bac5eb7836a3c90e37e870fd73d30b841fd (patch)
tree40443efd384415172cf393571fe3f1651ea57423 /Utility/Data.hs
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+{- utilities for simple data types
+ -
+ - Copyright 2013 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+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