CabalGild.Type.Optional

Documentation

data Optional a

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

Show a => Show (Optional a)

Defined in CabalGild.Type.Optional

Methods

showsPrec :: Int -> Optional a -> ShowS

show :: Optional a -> String

showList :: [Optional a] -> ShowS

Eq a => Eq (Optional a)

Defined in CabalGild.Type.Optional

Methods

(==) :: Optional a -> Optional a -> Bool

(/=) :: Optional a -> Optional a -> Bool

withDefault :: a -> Optional a -> a

Uses the provided default value if the optional is Default, otherwise gets the value out of the Specific. Similar to fromMaybe.

optional :: b -> (a -> b) -> Optional a -> b

Basic destructor, similar to maybe.