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Within LTS Haskell 24.51 (ghc-9.10.3)

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1. runMaybeT :: MaybeT (m :: Type -> Type) a -> m (Maybe a)

   ghc	GHC.Data.Maybe

   No documentation available.

2. tryMaybeT :: IO a -> MaybeT IO a

   ghc	GHC.Data.Maybe

   Try performing an IO action, failing on error.

3. fromMaybe :: a -> Maybe a -> a

   ghc	GHC.Data.Strict

   No documentation available.

4. filterMaybe :: (a -> Bool) -> Maybe a -> Maybe a

   ghc	GHC.Data.TrieMap

   No documentation available.

5. foldMaybe :: (a -> b -> b) -> Maybe a -> b -> b

   ghc	GHC.Data.TrieMap

   No documentation available.

6. apMaybeUB :: MaybeUB (a -> b) -> MaybeUB a -> MaybeUB b

   ghc	GHC.Data.Unboxed

   No documentation available.

7. fmapMaybeUB :: (a -> b) -> MaybeUB a -> MaybeUB b

   ghc	GHC.Data.Unboxed

   No documentation available.

8. fromMaybeUB :: a -> MaybeUB a -> a

   ghc	GHC.Data.Unboxed

   No documentation available.

9. mapMaybe :: (a -> Maybe b) -> Word64Map a -> Word64Map b

   ghc	GHC.Data.Word64Map.Internal

   Map values and collect the Just results.

   let f x = if x == "a" then Just "new a" else Nothing
   mapMaybe f (fromList [(5,"a"), (3,"b")]) == singleton 5 "new a"
   

10. mapMaybeMissing :: forall (f :: Type -> Type) x y . Applicative f => (Key -> x -> Maybe y) -> WhenMissing f x y

    ghc	GHC.Data.Word64Map.Internal

    Map over the entries whose keys are missing from the other map, optionally removing some. This is the most powerful SimpleWhenMissing tactic, but others are usually more efficient.

    mapMaybeMissing :: (Key -> x -> Maybe y) -> SimpleWhenMissing x y
    

    mapMaybeMissing f = traverseMaybeMissing (\k x -> pure (f k x))
    

    but mapMaybeMissing uses fewer unnecessary Applicative operations.

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