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Diffstat (limited to 'compiler/GHC/Utils/Misc.hs')
| -rw-r--r-- | compiler/GHC/Utils/Misc.hs | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/compiler/GHC/Utils/Misc.hs b/compiler/GHC/Utils/Misc.hs index 8f33944b86..3bc4e6adb8 100644 --- a/compiler/GHC/Utils/Misc.hs +++ b/compiler/GHC/Utils/Misc.hs @@ -30,7 +30,7 @@ module GHC.Utils.Misc ( mapAndUnzip, mapAndUnzip3, filterOut, partitionWith, - dropWhileEndLE, spanEnd, last2, lastMaybe, + dropWhileEndLE, spanEnd, last2, lastMaybe, onJust, List.foldl1', foldl2, count, countWhile, all2, @@ -764,6 +764,10 @@ lastMaybe :: [a] -> Maybe a lastMaybe [] = Nothing lastMaybe xs = Just $ last xs +-- | @onJust x m f@ applies f to the value inside the Just or returns the default. +onJust :: b -> Maybe a -> (a->b) -> b +onJust dflt = flip (maybe dflt) + -- | Split a list into its last element and the initial part of the list. -- @snocView xs = Just (init xs, last xs)@ for non-empty lists. -- @snocView xs = Nothing@ otherwise. |