Copyright	(c) incertia 2020
License	MIT
Maintainer	incertia@incertia.net
Stability	experimental
Portability	portable
Safe Haskell	Safe-Inferred
Language	Haskell2010

Data.As

Description

This module provides the As class which is a multi parameter classy prism, much like how Has is a multi parameter classy lens.

We have the following primary use case for As.

 -- some library code
 throwE :: (As e err, MonadError err m) => e -> m ()
 throwE = throwError . review asPrism

Synopsis

class As a t where
- previewer :: t -> Maybe a
- reviewer :: a -> t
- asPrism :: Prism t a
- modifier :: (a -> a) -> t -> t

Documentation

class As a t where Source #

A typeclass for extensible sums.

The provided instances were inspired from the lens library.

Making your own instances when you actually depend on lens should be as easy as instance As Foo Bar where asPrism = _Foo.

Minimal complete definition

previewer, reviewer | asPrism

Methods

previewer :: t -> Maybe a Source #

reviewer :: a -> t Source #

asPrism :: Prism t a Source #

modifier :: (a -> a) -> t -> t Source #

Instances

Instances details

(Read a, Show a) => As a String Source #
Instance details Defined in Data.As Methods previewer :: String -> Maybe a Source # reviewer :: a -> String Source # asPrism :: Prism String a Source # modifier :: (a -> a) -> String -> String Source #
As a a Source #
Instance details Defined in Data.As Methods previewer :: a -> Maybe a Source # reviewer :: a -> a Source # asPrism :: Prism a a Source # modifier :: (a -> a) -> a -> a Source #
As Void a Source #
Instance details Defined in Data.As Methods previewer :: a -> Maybe Void Source # reviewer :: Void -> a Source # asPrism :: Prism a Void Source # modifier :: (Void -> Void) -> a -> a Source #
As () (Maybe a) Source #
Instance details Defined in Data.As Methods previewer :: Maybe a -> Maybe () Source # reviewer :: () -> Maybe a Source # asPrism :: Prism (Maybe a) () Source # modifier :: (() -> ()) -> Maybe a -> Maybe a Source #
As a (Maybe a) Source #
Instance details Defined in Data.As Methods previewer :: Maybe a -> Maybe a Source # reviewer :: a -> Maybe a Source # asPrism :: Prism (Maybe a) a Source # modifier :: (a -> a) -> Maybe a -> Maybe a Source #
As b (Either a b) Source #
Instance details Defined in Data.As Methods previewer :: Either a b -> Maybe b Source # reviewer :: b -> Either a b Source # asPrism :: Prism (Either a b) b Source # modifier :: (b -> b) -> Either a b -> Either a b Source #
As a (Either a b) Source #
Instance details Defined in Data.As Methods previewer :: Either a b -> Maybe a Source # reviewer :: a -> Either a b Source # asPrism :: Prism (Either a b) a Source # modifier :: (a -> a) -> Either a b -> Either a b Source #