Foreign.Java.Value

The ternary value type, which can treither hold a value, nothing, or a special value describing an error condition.

Documentation

data Value e a

A ternary value type to hold one of two possible value types or none at all.

Constructors

Value a

An actual value

NoValue

No value

Fail e

A value describing the error

Instances

UnsafeCast a => ObjectResult (Value JThrowable a)

value

Arguments

:: b

default value if neither a value nor a fail value is given

-> (e -> b)

function to handle a fail value

-> (a -> b)

function to handle an actual value

-> Value e a

the value

-> b

the final return value

fold on a Value, like either for Either or maybe for Maybe.