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Within LTS Haskell 24.36 (ghc-9.10.3)
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xpWrapMaybe :: (a -> Maybe b, b -> a) -> PU a -> PU bhxt Text.XML.HXT.Arrow.Pickle like xpWrap, but if the inverse mapping is undefined, the unpickler fails Map a value into another domain. If the inverse mapping is undefined (Nothing), the unpickler fails Deprecated: Use xpWrapEither, this gives better error messages
liftMaybe :: String -> Maybe a -> Unpickler ahxt Text.XML.HXT.Arrow.Pickle.Xml Lift a Maybe value into the Unpickler monad. The 1. arg is the attached error message
xpLiftMaybe :: Maybe a -> PU ahxt Text.XML.HXT.Arrow.Pickle.Xml Lift a Maybe value to a pickler. Nothing is mapped to the zero pickler, Just x is pickled with xpLift x.
xpWrapMaybe :: (a -> Maybe b, b -> a) -> PU a -> PU bhxt Text.XML.HXT.Arrow.Pickle.Xml like xpWrap, but if the inverse mapping is undefined, the unpickler fails Map a value into another domain. If the inverse mapping is undefined (Nothing), the unpickler fails Deprecated: Use xpWrapEither, this gives better error messages
toMaybe :: Bool -> a -> Maybe ahxt Text.XML.HXT.DOM.Util No documentation available.
productMaybeWith :: (a -> b -> Maybe c) -> [[a]] -> [[b]] -> [[c]]leancheck Test.LeanCheck Take the product of lists of tiers by a function returning a Maybe value discarding Nothing values.
productMaybeWith :: (a -> b -> Maybe c) -> [[a]] -> [[b]] -> [[c]]leancheck Test.LeanCheck.Error Take the product of lists of tiers by a function returning a Maybe value discarding Nothing values.
funToListMaybe :: Listable a => (a -> b) -> [Maybe b]leancheck Test.LeanCheck.Function.List Converts a function to a list of Just result values or Nothing on error.
> take 6 $ funToListMaybe $ head :: [Maybe Int] [Nothing,Just 0,Just 0,Just 1,Just 0,Just 0]
This uses errorToNothing and consequently unsafePerformIO.catMaybesT :: [[Maybe a]] -> [[a]]leancheck Test.LeanCheck.Tiers Concatenate tiers of maybes
mapMaybeT :: (a -> Maybe b) -> [[a]] -> [[b]]leancheck Test.LeanCheck.Tiers Like mapMaybe but for tiers.