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Within LTS Haskell 22.19 (ghc-9.6.4)

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

base 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 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
""
```
maybe :: b -> (a -> b) -> Maybe a -> b

base Data.Maybe

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 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
""
```
maybe :: b -> (a -> b) -> Maybe a -> b

amazonka-core Amazonka.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 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
""
```
maybe :: MonadGen m => m a -> m (Maybe a)

hedgehog Hedgehog.Gen

Generates a Nothing some of the time.
maybe :: MonadGen m => m a -> m (Maybe a)

hedgehog Hedgehog.Internal.Gen

Generates a Nothing some of the time.
maybe :: b -> (a -> b) -> Maybe a -> b

hedgehog Hedgehog.Internal.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 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
""
```
maybe :: b -> (a -> b) -> Maybe a -> b

ghc GHC.Prelude.Basic

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 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
""
```
maybe :: b -> (a -> b) -> Maybe a -> b

rio RIO.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 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
""
```
maybe :: b -> (a -> b) -> Maybe a -> b

strict Data.Strict.Maybe

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

errors Control.Error

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 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
""
```

base	Prelude

base	Data.Maybe

amazonka-core	Amazonka.Prelude

hedgehog	Hedgehog.Gen

hedgehog	Hedgehog.Internal.Gen

hedgehog	Hedgehog.Internal.Prelude

ghc	GHC.Prelude.Basic

rio	RIO.Prelude

strict	Data.Strict.Maybe

errors	Control.Error

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