18 lines
425 B
Haskell
18 lines
425 B
Haskell
|
{- 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
|