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Within LTS Haskell 24.51 (ghc-9.10.3)

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  1. catMaybes :: (IsSequence (f (Maybe t)), Functor f, Element (f (Maybe t)) ~ Maybe t) => f (Maybe t) -> f t

    mono-traversable Data.Sequences

    Takes all of the Just values from a sequence of Maybe ts and concatenates them into an unboxed sequence of ts. Since 0.6.2

  2. leftToMaybe :: Either a b -> Maybe a

    either Data.Either.Combinators

    Maybe get the Left side of an Either. 

    leftToMaybe ≡ either Just (const Nothing)
    Using Control.Lens: 
    leftToMaybe ≡ preview _Left
leftToMaybe x ≡ x^?_Left

    >>> leftToMaybe (Left 12)
Just 12

    >>> leftToMaybe (Right 12)
Nothing

  3. rightToMaybe :: Either a b -> Maybe b

    either Data.Either.Combinators

    Maybe get the Right side of an Either. 

    rightToMaybe ≡ either (const Nothing) Just
    Using Control.Lens: 
    rightToMaybe ≡ preview _Right
rightToMaybe x ≡ x^?_Right

    >>> rightToMaybe (Left 12)
Nothing

    >>> rightToMaybe (Right 12)
Just 12

  4. fromMaybe :: e -> Maybe a -> Exceptional e a

    explicit-exception Control.Monad.Exception.Synchronous

    No documentation available.

  5. fromMaybeT :: forall (m :: Type -> Type) e a . Monad m => e -> MaybeT m a -> ExceptionalT e m a

    explicit-exception Control.Monad.Exception.Synchronous

    No documentation available.

  6. toMaybe :: Exceptional e a -> Maybe a

    explicit-exception Control.Monad.Exception.Synchronous

    No documentation available.

  7. toMaybeT :: forall (m :: Type -> Type) e a . Monad m => ExceptionalT e m a -> MaybeT m a

    explicit-exception Control.Monad.Exception.Synchronous

    No documentation available.

  8. contramapMaybeGLogFunc :: (a -> Maybe b) -> GLogFunc b -> GLogFunc a

    rio RIO

    A vesion of contramapMaybeGLogFunc which supports filering.

  9. indexMaybe :: ByteString -> Int -> Maybe Word8

    rio RIO.ByteString

    O(1) ByteString index, starting from 0, that returns Just if: 

    0 <= n < length bs

  10. mapMaybe :: (v1 -> Maybe v2) -> HashMap k v1 -> HashMap k v2

    rio RIO.HashMap

    Transform this map by applying a function to every value and retaining only some of them.

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