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  1. maybe :: b -> (a -> b) -> Maybe a -> b

    distribution-opensuse OpenSuse.Prelude

    The maybe function takes a default value, a function, and a Maybe value. If the Maybe value is Nothing, the function returns the default value. Otherwise, it applies the function to the value inside the Just and returns the result.

    Examples

    Basic usage: 
    >>> maybe False odd (Just 3)
True

    >>> maybe False odd Nothing
False
    Read an integer from a string using readMaybe. If we succeed, return twice the integer; that is, apply (*2) to it. If instead we fail to parse an integer, return 0 by default: 
    >>> import GHC.Internal.Text.Read ( readMaybe )

>>> maybe 0 (*2) (readMaybe "5")
10

>>> maybe 0 (*2) (readMaybe "")
0
    Apply show to a Maybe Int. If we have Just n, we want to show the underlying Int n. But if we have Nothing, we return the empty string instead of (for example) "Nothing": 
    >>> maybe "" show (Just 5)
"5"

>>> maybe "" show Nothing
""

  2. maybe :: b -> (a -> b) -> Maybe a -> b

    faktory Faktory.Prelude

    The maybe function takes a default value, a function, and a Maybe value. If the Maybe value is Nothing, the function returns the default value. Otherwise, it applies the function to the value inside the Just and returns the result.

    Examples

    Basic usage: 
    >>> maybe False odd (Just 3)
True

    >>> maybe False odd Nothing
False
    Read an integer from a string using readMaybe. If we succeed, return twice the integer; that is, apply (*2) to it. If instead we fail to parse an integer, return 0 by default: 
    >>> import GHC.Internal.Text.Read ( readMaybe )

>>> maybe 0 (*2) (readMaybe "5")
10

>>> maybe 0 (*2) (readMaybe "")
0
    Apply show to a Maybe Int. If we have Just n, we want to show the underlying Int n. But if we have Nothing, we return the empty string instead of (for example) "Nothing": 
    >>> maybe "" show (Just 5)
"5"

>>> maybe "" show Nothing
""

  3. maybe :: (AbsRel ar, FileDir fd) => String -> Maybe (Path ar fd)

    pathtype System.Path

    No documentation available.

  4. maybe :: (System os, AbsRel ar, FileDir fd) => String -> Maybe (Path os ar fd)

    pathtype System.Path.Generic

    This function is intended for checking and parsing paths provided as user input. 

    fmap Posix.toString (Posix.maybePath "/" :: Maybe Posix.AbsDir) == Just "/"

    fmap Posix.toString (Posix.maybePath "/" :: Maybe Posix.AbsFile) == Nothing

    fmap Posix.toString (Posix.maybePath "/" :: Maybe Posix.RelDir) == Nothing

    fmap Posix.toString (Posix.maybePath "/" :: Maybe Posix.RelFile) == Nothing

    fmap Posix.toString (Posix.maybePath "/tmp" :: Maybe Posix.AbsDir) == Just "/tmp"

    fmap Posix.toString (Posix.maybePath "/tmp" :: Maybe Posix.AbsFile) == Just "/tmp"

    fmap Posix.toString (Posix.maybePath "/tmp" :: Maybe Posix.RelDir) == Nothing

    fmap Posix.toString (Posix.maybePath "/tmp" :: Maybe Posix.RelFile) == Nothing

    fmap Posix.toString (Posix.maybePath "/tmp/" :: Maybe Posix.AbsDir) == Just "/tmp"

    fmap Posix.toString (Posix.maybePath "/tmp/" :: Maybe Posix.AbsFile) == Nothing

    fmap Posix.toString (Posix.maybePath "/tmp/" :: Maybe Posix.RelDir) == Nothing

    fmap Posix.toString (Posix.maybePath "/tmp/" :: Maybe Posix.RelFile) == Nothing

    fmap Posix.toString (Posix.maybePath "/tmp" :: Maybe Posix.AbsRelFileDir) == Just "/tmp"

    fmap Posix.toString (Posix.maybePath "/tmp/" :: Maybe Posix.AbsRelFileDir) == Just "/tmp"

    fmap Posix.toString (Posix.maybePath "file.txt" :: Maybe Posix.RelFile) == Just "file.txt"

    fmap Posix.toString (Posix.maybePath "file.txt" :: Maybe Posix.AbsFile) == Nothing

    fmap Windows.toString (Windows.maybePath "\\tmp" :: Maybe Windows.AbsDir) == Just "\\tmp"

    fmap Windows.toString (Windows.maybePath "a:\\tmp" :: Maybe Windows.AbsDir) == Just "a:\\tmp"

    fmap Windows.toString (Windows.maybePath "a:tmp" :: Maybe Windows.AbsDir) == Just "a:tmp"

    fmap Windows.toString (Windows.maybePath "a:\\" :: Maybe Windows.AbsDir) == Just "a:\\"

    fmap Windows.toString (Windows.maybePath "a:" :: Maybe Windows.AbsDir) == Just "a:"

    fmap Windows.toString (Windows.maybePath "tmp" :: Maybe Windows.RelDir) == Just "tmp"

    fmap Windows.toString (Windows.maybePath "\\tmp" :: Maybe Windows.RelDir) == Nothing

    fmap Windows.toString (Windows.maybePath "a:\\tmp" :: Maybe Windows.RelDir) == Nothing

    fmap Windows.toString (Windows.maybePath "a:tmp" :: Maybe Windows.RelDir) == Nothing

    fmap Windows.toString (Windows.maybePath "tmp" :: Maybe Windows.AbsDir) == Nothing

  5. maybe :: (AbsRel ar, FileDir fd) => String -> Maybe (Path ar fd)

    pathtype System.Path.Posix

    No documentation available.

  6. maybe :: (AbsRel ar, FileDir fd) => String -> Maybe (Path ar fd)

    pathtype System.Path.Windows

    No documentation available.

  7. maybe :: Schema -> Schema

    rattletrap Rattletrap.Schema

    No documentation available.

  8. maybe :: b -> (a -> b) -> Maybe a -> b

    strict-base-types Data.Maybe.Strict

    Given a default value, a function and a Maybe value, yields the default value if the Maybe value is Nothing and applies the function to the value stored in the Just otherwise.

  9. maybe :: b -> (a -> b) -> Maybe a -> b

    classy-prelude-yesod ClassyPrelude.Yesod

    The maybe function takes a default value, a function, and a Maybe value. If the Maybe value is Nothing, the function returns the default value. Otherwise, it applies the function to the value inside the Just and returns the result.

    Examples

    Basic usage: 
    >>> maybe False odd (Just 3)
True

    >>> maybe False odd Nothing
False
    Read an integer from a string using readMaybe. If we succeed, return twice the integer; that is, apply (*2) to it. If instead we fail to parse an integer, return 0 by default: 
    >>> import GHC.Internal.Text.Read ( readMaybe )

>>> maybe 0 (*2) (readMaybe "5")
10

>>> maybe 0 (*2) (readMaybe "")
0
    Apply show to a Maybe Int. If we have Just n, we want to show the underlying Int n. But if we have Nothing, we return the empty string instead of (for example) "Nothing": 
    >>> maybe "" show (Just 5)
"5"

>>> maybe "" show Nothing
""

  10. maybe :: b -> (a -> b) -> Maybe a -> b

    constrained-categories Control.Category.Constrained.Prelude

    The maybe function takes a default value, a function, and a Maybe value. If the Maybe value is Nothing, the function returns the default value. Otherwise, it applies the function to the value inside the Just and returns the result.

    Examples

    Basic usage: 
    >>> maybe False odd (Just 3)
True

    >>> maybe False odd Nothing
False
    Read an integer from a string using readMaybe. If we succeed, return twice the integer; that is, apply (*2) to it. If instead we fail to parse an integer, return 0 by default: 
    >>> import GHC.Internal.Text.Read ( readMaybe )

>>> maybe 0 (*2) (readMaybe "5")
10

>>> maybe 0 (*2) (readMaybe "")
0
    Apply show to a Maybe Int. If we have Just n, we want to show the underlying Int n. But if we have Nothing, we return the empty string instead of (for example) "Nothing": 
    >>> maybe "" show (Just 5)
"5"

>>> maybe "" show Nothing
""

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