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Diffstat (limited to 'compiler/GHC/Utils/Misc.hs')
| -rw-r--r-- | compiler/GHC/Utils/Misc.hs | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/compiler/GHC/Utils/Misc.hs b/compiler/GHC/Utils/Misc.hs index 29cad99cd3..8f33944b86 100644 --- a/compiler/GHC/Utils/Misc.hs +++ b/compiler/GHC/Utils/Misc.hs @@ -52,6 +52,10 @@ module GHC.Utils.Misc ( mergeListsBy, isSortedBy, + -- Foldable generalised functions, + + mapMaybe', + -- * Tuples fstOf3, sndOf3, thdOf3, firstM, first3M, secondM, @@ -1468,3 +1472,10 @@ type HasDebugCallStack = HasCallStack #else type HasDebugCallStack = (() :: Constraint) #endif + +mapMaybe' :: Foldable f => (a -> Maybe b) -> f a -> [b] +mapMaybe' f = foldr g [] + where + g x rest + | Just y <- f x = y : rest + | otherwise = rest |