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1. maybeCons1 :: Listable a => (a -> Maybe b) -> [[b]]

   leancheck	Test.LeanCheck.Tiers

   Like cons1 but lifted over a Maybe result. This discard Nothing values. Only Just values are returned.

2. maybeCons2 :: (Listable a, Listable b) => (a -> b -> Maybe c) -> [[c]]

   leancheck	Test.LeanCheck.Tiers

   Like cons2 but lifted over a Maybe result. This discard Nothing values. Only Just values are returned. Useful when declaring generators which have pre-conditions:

   data Fraction  =  Fraction Int Int
   
   mkFraction _ 0  =  Nothing
   mkFraction n d  =  Fraction n d
   
   instance Listable Fraction where
   tiers  =  maybeCons2 mkFraction
   

3. maybeRead :: Read a => String -> Maybe a

   ghc-boot	GHC.Settings.Utils

   No documentation available.

4. maybeReadFuzzy :: Read a => String -> Maybe a

   ghc-boot	GHC.Settings.Utils

   No documentation available.

5. maybeAt :: Int -> [a] -> Maybe a

   relude	Relude.List

   !!? with its arguments flipped. Get element from list using index value starting from `0`.

   >>> maybeAt 0 []
   Nothing
   

   >>> maybeAt 3 ["a", "b", "c"]
   Nothing
   

   >>> maybeAt (-1) [1, 2, 3]
   Nothing
   

   >>> maybeAt 2 ["a", "b", "c"]
   Just "c"
   

6. maybeToLeft :: r -> Maybe l -> Either l r

   relude	Relude.Monad.Either

   Maps Maybe to Either wrapping default value into Right.

   >>> maybeToLeft True (Just "aba")
   Left "aba"
   
   >>> maybeToLeft True Nothing
   Right True
   

7. maybeToRight :: l -> Maybe r -> Either l r

   relude	Relude.Monad.Either

   Maps Maybe to Either wrapping default value into Left.

   >>> maybeToRight True (Just "aba")
   Right "aba"
   
   >>> maybeToRight True Nothing
   Left True
   

8. maybeToExceptT :: forall (m :: Type -> Type) e a . Functor m => e -> MaybeT m a -> ExceptT e m a

   relude	Relude.Monad.Reexport

   Convert a MaybeT computation to ExceptT, with a default exception value.

9. maybeToList :: Maybe a -> [a]

   relude	Relude.Monad.Reexport

   The maybeToList function returns an empty list when given Nothing or a singleton list when given Just.

   Examples

   Basic usage:

   >>> maybeToList (Just 7)
   [7]
   

   >>> maybeToList Nothing
   []
   

   One can use maybeToList to avoid pattern matching when combined with a function that (safely) works on lists:

   >>> import GHC.Internal.Text.Read ( readMaybe )
   
   >>> sum $ maybeToList (readMaybe "3")
   3
   
   >>> sum $ maybeToList (readMaybe "")
   0
   

10. maybeToMonoid :: Monoid m => Maybe m -> m

    relude	Relude.Monoid

    Extracts Monoid value from Maybe returning mempty if Nothing.

    >>> maybeToMonoid (Just [1,2,3] :: Maybe [Int])
    [1,2,3]
    
    >>> maybeToMonoid (Nothing :: Maybe [Int])
    []
    

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