Copyright	(C) 2015-2016 Edward Kmett Ryan Scott
License	BSD-style (see the file LICENSE)
Maintainer	Ryan Scott
Stability	Provisional
Portability	GHC
Safe Haskell	None
Language	Haskell2010

Data.Functor.Classes.Generic

Contents

Options
Eq1
Ord1
Read1
Show1
GenericFunctorClasses
Example

Description

Functions to generically derive Eq1, Ord1, Read1, and Show1 instances from Data.Functor.Classes.

Synopsis

data Options = Options
defaultOptions :: Options
latestGHCOptions :: Options
liftEqDefault :: (GEq1 (Rep1 f), Generic1 f) => (a -> b -> Bool) -> f a -> f b -> Bool
liftEqOptions :: (GEq1 (Rep1 f), Generic1 f) => Options -> (a -> b -> Bool) -> f a -> f b -> Bool
liftCompareDefault :: (GOrd1 (Rep1 f), Generic1 f) => (a -> b -> Ordering) -> f a -> f b -> Ordering
liftCompareOptions :: (GOrd1 (Rep1 f), Generic1 f) => Options -> (a -> b -> Ordering) -> f a -> f b -> Ordering
liftReadsPrecDefault :: (GRead1 (Rep1 f), Generic1 f) => (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (f a)
liftReadsPrecOptions :: (GRead1 (Rep1 f), Generic1 f) => Options -> (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (f a)
liftShowsPrecDefault :: (GShow1 (Rep1 f), Generic1 f) => (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> f a -> ShowS
liftShowsPrecOptions :: (GShow1 (Rep1 f), Generic1 f) => Options -> (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> f a -> ShowS
newtype FunctorClassesDefault (f :: Type -> Type) a = FunctorClassesDefault {
- getFunctorClassesDefault :: f a
}

Options

data Options Source #

Options that further configure how the functions in Data.Functor.Classes.Generic should behave. Currently, the Options have no effect (but this may change in the future).

Constructors

Options

defaultOptions :: Options Source #

Options that match the behavior of the installed version of GHC.

latestGHCOptions :: Options Source #

Options that match the behavior of the most recent GHC release.

`Eq1`

liftEqDefault :: (GEq1 (Rep1 f), Generic1 f) => (a -> b -> Bool) -> f a -> f b -> Bool Source #

A sensible default liftEq implementation for Generic1 instances.

liftEqOptions :: (GEq1 (Rep1 f), Generic1 f) => Options -> (a -> b -> Bool) -> f a -> f b -> Bool Source #

Like liftEqDefault, but with configurable Options. Currently, the Options have no effect (but this may change in the future).

`Ord1`

liftCompareDefault :: (GOrd1 (Rep1 f), Generic1 f) => (a -> b -> Ordering) -> f a -> f b -> Ordering Source #

A sensible default liftCompare implementation for Generic1 instances.

liftCompareOptions :: (GOrd1 (Rep1 f), Generic1 f) => Options -> (a -> b -> Ordering) -> f a -> f b -> Ordering Source #

Like liftCompareDefault, but with configurable Options. Currently, the Options have no effect (but this may change in the future).

`Read1`

liftReadsPrecDefault :: (GRead1 (Rep1 f), Generic1 f) => (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (f a) Source #

A sensible default liftReadsPrec implementation for Generic1 instances.

liftReadsPrecOptions :: (GRead1 (Rep1 f), Generic1 f) => Options -> (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (f a) Source #

Like liftReadsPrecDefault, but with configurable Options. Currently, the Options have no effect (but this may change in the future).

`Show1`

liftShowsPrecDefault :: (GShow1 (Rep1 f), Generic1 f) => (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> f a -> ShowS Source #

A sensible default liftShowsPrec implementation for Generic1 instances.

liftShowsPrecOptions :: (GShow1 (Rep1 f), Generic1 f) => Options -> (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> f a -> ShowS Source #

Like liftShowsPrecDefault, but with configurable Options. Currently, the Options have no effect (but this may change in the future).

`GenericFunctorClasses`

newtype FunctorClassesDefault (f :: Type -> Type) a Source #

An adapter newtype, suitable for DerivingVia. Its Eq1, Ord1, Read1, and Show1 instances leverage Generic1-based defaults.

Constructors

FunctorClassesDefault
Fields getFunctorClassesDefault :: f a

Instances

Instances details

(GEq1 (Rep1 f), Generic1 f) => Eq1 (FunctorClassesDefault f) Source #
Instance details Defined in Data.Functor.Classes.Generic.Internal Methods liftEq :: (a -> b -> Bool) -> FunctorClassesDefault f a -> FunctorClassesDefault f b -> Bool #
(GOrd1 (Rep1 f), Generic1 f) => Ord1 (FunctorClassesDefault f) Source #
Instance details Defined in Data.Functor.Classes.Generic.Internal Methods liftCompare :: (a -> b -> Ordering) -> FunctorClassesDefault f a -> FunctorClassesDefault f b -> Ordering #
(GRead1 (Rep1 f), Generic1 f) => Read1 (FunctorClassesDefault f) Source #
Instance details Defined in Data.Functor.Classes.Generic.Internal Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (FunctorClassesDefault f a) # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [FunctorClassesDefault f a] # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (FunctorClassesDefault f a) # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [FunctorClassesDefault f a] #
(GShow1 (Rep1 f), Generic1 f) => Show1 (FunctorClassesDefault f) Source #
Instance details Defined in Data.Functor.Classes.Generic.Internal Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> FunctorClassesDefault f a -> ShowS # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [FunctorClassesDefault f a] -> ShowS #
(GEq (Rep1 f a), Generic1 f) => Eq (FunctorClassesDefault f a) Source #
Instance details Defined in Data.Functor.Classes.Generic.Internal Methods (==) :: FunctorClassesDefault f a -> FunctorClassesDefault f a -> Bool # (/=) :: FunctorClassesDefault f a -> FunctorClassesDefault f a -> Bool #
(GOrd (Rep1 f a), Generic1 f) => Ord (FunctorClassesDefault f a) Source #
Instance details Defined in Data.Functor.Classes.Generic.Internal Methods compare :: FunctorClassesDefault f a -> FunctorClassesDefault f a -> Ordering # (<) :: FunctorClassesDefault f a -> FunctorClassesDefault f a -> Bool # (<=) :: FunctorClassesDefault f a -> FunctorClassesDefault f a -> Bool # (>) :: FunctorClassesDefault f a -> FunctorClassesDefault f a -> Bool # (>=) :: FunctorClassesDefault f a -> FunctorClassesDefault f a -> Bool # max :: FunctorClassesDefault f a -> FunctorClassesDefault f a -> FunctorClassesDefault f a # min :: FunctorClassesDefault f a -> FunctorClassesDefault f a -> FunctorClassesDefault f a #
(GRead (Rep1 f a), Generic1 f) => Read (FunctorClassesDefault f a) Source #
Instance details Defined in Data.Functor.Classes.Generic.Internal Methods readsPrec :: Int -> ReadS (FunctorClassesDefault f a) # readList :: ReadS [FunctorClassesDefault f a] # readPrec :: ReadPrec (FunctorClassesDefault f a) # readListPrec :: ReadPrec [FunctorClassesDefault f a] #
(GShow (Rep1 f a), Generic1 f) => Show (FunctorClassesDefault f a) Source #
Instance details Defined in Data.Functor.Classes.Generic.Internal Methods showsPrec :: Int -> FunctorClassesDefault f a -> ShowS # show :: FunctorClassesDefault f a -> String # showList :: [FunctorClassesDefault f a] -> ShowS #

Example

The most straightforward way to use the defaults in this module is to use DerivingVia on GHC 8.6 or later. For example:

{-# LANGUAGE DeriveGeneric, DerivingVia #-}

import Data.Functor.Classes
import Data.Functor.Classes.Generic
import GHC.Generics

data Pair a = Pair a a
  deriving stock Generic1
  deriving (Eq1, Ord1, Read1, Show1)
           via FunctorClassesDefault Pair

If using an older version of GHC, then one can also define instances manually. Here is an example:

{-# LANGUAGE DeriveGeneric #-}

import Data.Functor.Classes
import Data.Functor.Classes.Generic
import GHC.Generics

data Pair a = Pair a a deriving Generic1

instance Eq1 Pair where
    liftEq = liftEqDefault

instance Ord1 Pair where
    liftCompare = liftCompareDefault

instance Read1 Pair where
    liftReadsPrec = liftReadsPrecDefault

instance Show1 Pair where
    liftShowsPrec = liftShowsPrecDefault