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  1. fromMaybe :: a -> Maybe a -> a

    basic-prelude CorePrelude

    The fromMaybe function takes a default value and a Maybe value. If the Maybe is Nothing, it returns the default value; otherwise, it returns the value contained in the Maybe.

    Examples

    Basic usage: 
    >>> fromMaybe "" (Just "Hello, World!")
"Hello, World!"

    >>> fromMaybe "" Nothing
""
    Read an integer from a string using readMaybe. If we fail to parse an integer, we want to return 0 by default: 
    >>> import GHC.Internal.Text.Read ( readMaybe )

>>> fromMaybe 0 (readMaybe "5")
5

>>> fromMaybe 0 (readMaybe "")
0

  2. fromMaybe :: a -> Maybe a -> a

    classy-prelude ClassyPrelude

    The fromMaybe function takes a default value and a Maybe value. If the Maybe is Nothing, it returns the default value; otherwise, it returns the value contained in the Maybe.

    Examples

    Basic usage: 
    >>> fromMaybe "" (Just "Hello, World!")
"Hello, World!"

    >>> fromMaybe "" Nothing
""
    Read an integer from a string using readMaybe. If we fail to parse an integer, we want to return 0 by default: 
    >>> import GHC.Internal.Text.Read ( readMaybe )

>>> fromMaybe 0 (readMaybe "5")
5

>>> fromMaybe 0 (readMaybe "")
0

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

    ghc-lib-parser GHC.Data.Strict

    No documentation available.

  4. fromMaybe :: (Steppable (->) t (Either a), Corecursive (->) t (Either a)) => Maybe a -> t

    yaya Yaya.Applied

    Converts exceptional divergence to non-termination.

  5. fromMaybe :: a -> Maybe a -> a

    foundation Foundation

    The fromMaybe function takes a default value and a Maybe value. If the Maybe is Nothing, it returns the default value; otherwise, it returns the value contained in the Maybe.

    Examples

    Basic usage: 
    >>> fromMaybe "" (Just "Hello, World!")
"Hello, World!"

    >>> fromMaybe "" Nothing
""
    Read an integer from a string using readMaybe. If we fail to parse an integer, we want to return 0 by default: 
    >>> import GHC.Internal.Text.Read ( readMaybe )

>>> fromMaybe 0 (readMaybe "5")
5

>>> fromMaybe 0 (readMaybe "")
0

  6. fromMaybe :: a -> Maybe a -> a

    massiv-test Test.Massiv.Utils

    The fromMaybe function takes a default value and a Maybe value. If the Maybe is Nothing, it returns the default value; otherwise, it returns the value contained in the Maybe.

    Examples

    Basic usage: 
    >>> fromMaybe "" (Just "Hello, World!")
"Hello, World!"

    >>> fromMaybe "" Nothing
""
    Read an integer from a string using readMaybe. If we fail to parse an integer, we want to return 0 by default: 
    >>> import GHC.Internal.Text.Read ( readMaybe )

>>> fromMaybe 0 (readMaybe "5")
5

>>> fromMaybe 0 (readMaybe "")
0

  7. fromMaybe :: (OperatorContext c, HasColumnConstraint NotNull r) => Record c r -> Record c (Maybe r) -> Record c r

    relational-query Database.Relational.Arrow

    Operator from maybe type using record extended isNull.

  8. fromMaybe :: (OperatorContext c, HasColumnConstraint NotNull r) => Record c r -> Record c (Maybe r) -> Record c r

    relational-query Database.Relational.Projectable

    Operator from maybe type using record extended isNull.

  9. fromMaybe :: a -> Maybe a -> a

    cabal-install-solver Distribution.Solver.Compat.Prelude

    The fromMaybe function takes a default value and a Maybe value. If the Maybe is Nothing, it returns the default value; otherwise, it returns the value contained in the Maybe.

    Examples

    Basic usage: 
    >>> fromMaybe "" (Just "Hello, World!")
"Hello, World!"

    >>> fromMaybe "" Nothing
""
    Read an integer from a string using readMaybe. If we fail to parse an integer, we want to return 0 by default: 
    >>> import GHC.Internal.Text.Read ( readMaybe )

>>> fromMaybe 0 (readMaybe "5")
5

>>> fromMaybe 0 (readMaybe "")
0

  10. fromMaybe :: forall c (f :: Type -> Type) a . c -> Colonnade f a c -> Colonnade f (Maybe a) c

    colonnade Colonnade

    Lift a column over a Maybe. For example, if some people have houses and some do not, the data that pairs them together could be represented as: 

    >>> :{
let owners :: [(Person,Maybe House)]
owners =
[ (Person "Jordan" 18, Nothing)
, (Person "Ruth" 25, Just (House Red 125000))
, (Person "Sonia" 12, Just (House Green 145000))
]
:}
    The column encodings defined earlier can be reused with the help of fromMaybe: 
    >>> :{
let colOwners :: Colonnade Headed (Person,Maybe House) String
colOwners = mconcat
[ lmap fst colPerson
, lmap snd (fromMaybe "" colHouse)
]
:}

    >>> putStr (ascii colOwners owners)
+--------+-----+-------+---------+
| Name   | Age | Color | Price   |
+--------+-----+-------+---------+
| Jordan | 18  |       |         |
| Ruth   | 25  | Red   | $125000 |
| Sonia  | 12  | Green | $145000 |
+--------+-----+-------+---------+

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