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

newtype Options = Options {
- ghc8ShowBehavior :: Bool
}
defaultOptions :: Options
latestGHCOptions :: Options
liftEqDefault :: (GEq1 NonV4 (Rep1 f), Generic1 f) => (a -> b -> Bool) -> f a -> f b -> Bool
liftEqOptions :: (GEq1 NonV4 (Rep1 f), Generic1 f) => Options -> (a -> b -> Bool) -> f a -> f b -> Bool
liftCompareDefault :: (GOrd1 NonV4 (Rep1 f), Generic1 f) => (a -> b -> Ordering) -> f a -> f b -> Ordering
liftCompareOptions :: (GOrd1 NonV4 (Rep1 f), Generic1 f) => Options -> (a -> b -> Ordering) -> f a -> f b -> Ordering
liftReadsPrecDefault :: (GRead1 NonV4 (Rep1 f), Generic1 f) => (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (f a)
liftReadsPrecOptions :: (GRead1 NonV4 (Rep1 f), Generic1 f) => Options -> (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (f a)
liftShowsPrecDefault :: (GShow1 NonV4 (Rep1 f), Generic1 f) => (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> f a -> ShowS
liftShowsPrecOptions :: (GShow1 NonV4 (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

newtype Options Source #

Options that further configure how the functions in Data.Functor.Classes.Generic should behave.

Constructors

Options
Fields ghc8ShowBehavior :: Bool If `True`, a default `Show1` implementation will show hash signs (`#`) when showing unlifted types.

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 NonV4 (Rep1 f), Generic1 f) => (a -> b -> Bool) -> f a -> f b -> Bool Source #

A sensible default liftEq implementation for Generic1 instances.

liftEqOptions :: (GEq1 NonV4 (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 NonV4 (Rep1 f), Generic1 f) => (a -> b -> Ordering) -> f a -> f b -> Ordering Source #

A sensible default liftCompare implementation for Generic1 instances.

liftCompareOptions :: (GOrd1 NonV4 (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 NonV4 (Rep1 f), Generic1 f) => (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (f a) Source #

A sensible default liftReadsPrec implementation for Generic1 instances.

liftReadsPrecOptions :: (GRead1 NonV4 (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 NonV4 (Rep1 f), Generic1 f) => (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> f a -> ShowS Source #

A sensible default liftShowsPrec implementation for Generic1 instances.

liftShowsPrecOptions :: (GShow1 NonV4 (Rep1 f), Generic1 f) => Options -> (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> f a -> ShowS Source #

Like liftShowsPrecDefault, but with configurable Options.

`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 NonV4 (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 NonV4 (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 NonV4 (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 NonV4 (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 #
(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 #
(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 #

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. This is slightly trickier to accomplish since this module exports different functions depending on which version of transformers this library is built against. Here is an example of how to define instances manually:

{-# LANGUAGE CPP, 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
#if MIN_VERSION_transformers(0,4,0) && !(MIN_VERSION_transformers(0,5,0))
    eq1 = eq1Default
#else
    liftEq = liftEqDefault
#endif

instance Ord1 Pair where
#if MIN_VERSION_transformers(0,4,0) && !(MIN_VERSION_transformers(0,5,0))
    compare1 = compare1Default
#else
    liftCompare = liftCompareDefault
#endif

instance Read1 Pair where
#if MIN_VERSION_transformers(0,4,0) && !(MIN_VERSION_transformers(0,5,0))
    readsPrec1 = readsPrec1Default
#else
    liftReadsPrec = liftReadsPrecDefault
#endif

instance Show1 Pair where
#if MIN_VERSION_transformers(0,4,0) && !(MIN_VERSION_transformers(0,5,0))
    showsPrec1 = showsPrec1Default
#else
    liftShowsPrec = liftShowsPrecDefault
#endif