Data.Functor.MaybeLike

Type constructors which can be turned into Maybe.

Documentation

class MaybeLike f where

This class may be defined in two ways:

• Type constructors which can be turned into Maybe generically.
• Type constructors which admit a natural transformation to Maybe.

We expect the following rules to hold for those instances of MaybeLike which are also Alternative:

• likeMaybe empty = empty = Nothing

• likeMaybe (x | y) = likeMaybe x | likeMaybe y

Methods

likeMaybe :: f a -> Maybe a

Instances

MaybeLike Maybe

Defined in Data.Functor.MaybeLike

Methods

likeMaybe :: Maybe a -> Maybe a

MaybeLike Identity

Defined in Data.Functor.MaybeLike

Methods

likeMaybe :: Identity a -> Maybe a

MaybeLike (Either a)

Defined in Data.Functor.MaybeLike

Methods

likeMaybe :: Either a a0 -> Maybe a0