Safe Haskell	Safe-Inferred
Language	Haskell2010

CabalGild.Unstable.Type.Optional

Synopsis

data Optional a
- = Default
- | Specific a
fromMaybe :: Maybe a -> Optional a
toMaybe :: Optional a -> Maybe a

Documentation

data Optional a Source #

Represents a value that may or may not be present. Isomorphic to Maybe. Useful to distinguish between a value not being given and a value happening to be the same as the default.

Constructors

Default
Specific a

Instances

Instances details

Show a => Show (Optional a) Source #
Instance details Defined in CabalGild.Unstable.Type.Optional Methods showsPrec :: Int -> Optional a -> ShowS # show :: Optional a -> String # showList :: [Optional a] -> ShowS #
Eq a => Eq (Optional a) Source #
Instance details Defined in CabalGild.Unstable.Type.Optional Methods (==) :: Optional a -> Optional a -> Bool # (/=) :: Optional a -> Optional a -> Bool #

fromMaybe :: Maybe a -> Optional a Source #

Converts a Maybe value into an Optional one.

toMaybe :: Optional a -> Maybe a Source #

Converts an Optional value into a Maybe one.