Data.Functor.Classes.Generic

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

Options

newtype Options

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

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

latestGHCOptions :: Options

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

A sensible default liftEq implementation for Generic1 instances.

liftEqOptions :: (GEq1 NonV4 (Rep1 f), Generic1 f) => Options -> (a -> b -> Bool) -> f a -> f b -> Bool

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

A sensible default liftCompare implementation for Generic1 instances.

liftCompareOptions :: (GOrd1 NonV4 (Rep1 f), Generic1 f) => Options -> (a -> b -> Ordering) -> f a -> f b -> Ordering

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)

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)

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

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

Like liftShowsPrecDefault, but with configurable Options.

Example

Note that this module exports different functions depending on which version of transformers this library is built against. Here is an example of how to use this module correctly:

{-# 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
#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