Data.Maybe
The `Data.Maybe type encapsulates an optional value.
A value of type Data.Maybe<a>
either contains a
value of type a
(represented as just(a)
), or it
is empty (represented as nothing
). Using
Data.Maybe
is a good way to deal with errors or
exceptional cases without resorting to drastic
measures such as error.
The Data.Maybe
type is also a monad. It is a
simple kind of error monad, where all errors are
represented by nothing
. A richer error monad can be
built using the Data.Either
type.
Summary
Functions
Instantiates Data.Maybe
value containing v
of
type term
Instantiates an “empty” Data.Maybe
value
Types
t :: %Data.Maybe{just: term, nothing: boolean}