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1. runMaybeApply :: MaybeApply (f :: Type -> Type) a -> Either (f a) a

   semigroupoids	Data.Functor.Bind.Class

   No documentation available.

2. traverse1Maybe :: (Traversable t, Apply f) => (a -> f b) -> t a -> MaybeApply f (t b)

   semigroupoids	Data.Functor.Bind.Class

   Traverse a Traversable using Apply, getting the results back in a MaybeApply.

3. traverse1Maybe :: (Traversable t, Apply f) => (a -> f b) -> t a -> MaybeApply f (t b)

   semigroupoids	Data.Semigroup.Traversable

   Traverse a Traversable using Apply, getting the results back in a MaybeApply.

4. minusNaturalMaybe :: Natural -> Natural -> Maybe Natural

   base-compat	Numeric.Natural.Compat

   Natural subtraction. Returns Nothings for non-positive results.

5. readMaybe :: Read a => String -> Maybe a

   base-compat	Text.Read.Compat

   Parse a string using the Read instance. Succeeds if there is exactly one valid result.

   >>> readMaybe "123" :: Maybe Int
   Just 123
   

   >>> readMaybe "hello" :: Maybe Int
   Nothing
   

6. partitionMaybe :: (a -> Maybe b) -> [a] -> ([b], [a])

   utility-ht	Data.List.HT

   Partition a list into elements which evaluate to Just or Nothing by f.

   forAllMaybeFn $ \f xs -> partitionMaybe f xs == (mapMaybe f xs, filter (isNothing . f) xs)
   

   forAllPredicates $ \p xs -> partition p xs == partitionMaybe (\x -> toMaybe (p x) x) xs
   

7. segmentAfterMaybe :: (a -> Maybe b) -> [a] -> ([([a], b)], [a])

   utility-ht	Data.List.HT

   Deprecated: use segmentAfterJust instead

8. segmentBeforeMaybe :: (a -> Maybe b) -> [a] -> ([a], [(b, [a])])

   utility-ht	Data.List.HT

   Deprecated: use segmentBeforeJust instead

9. toMaybe :: Bool -> a -> Maybe a

   utility-ht	Data.Maybe.HT

   Returns Just if the precondition is fulfilled. prop> b x -> (guard b >> x) == (toMaybe b =<< (x::Maybe Char))

10. mapMaybe :: forall (m :: Type -> Type) a b . Functor m => (a -> Maybe b) -> SourceT m a -> SourceT m b

    servant	Servant.Types.SourceT

    Filter values.

    >>> toList $ mapMaybe (\x -> if odd x then Just x else Nothing) (source [0..10]) :: [Int]
    [1,3,5,7,9]
    

    >>> mapMaybe (\x -> if odd x then Just x else Nothing) (source [0..2]) :: SourceT Identity Int
    fromStepT (Effect (Identity (Skip (Yield 1 (Skip Stop)))))
    

    Illustrates why we need Skip.

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