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authorJoey Hess <joeyh@debian.org>2014-04-11 01:19:05 -0400
committerJoey Hess <joeyh@debian.org>2014-04-11 01:19:05 -0400
commitbe02ef96aa89a6af554a622f266d700ac0c98fdf (patch)
tree63c784022afb05b73fedf0df3fd269de0d31baf8 /Utility/Data.hs
propellor (0.3.0) unstable; urgency=medium
* ipv6to4: Ensure interface is brought up automatically on boot. * Enabling unattended upgrades now ensures that cron is installed and running to perform them. * Properties can be scheduled to only be checked after a given time period. * Fix bootstrapping of dependencies. * Fix compilation on Debian stable. * Include security updates in sources.list for stable and testing. * Use ssh connection caching, especially when bootstrapping. * Properties now run in a Propellor monad, which provides access to attributes of the host. # imported from the archive
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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