Copyright	(c) Ross Paterson 2013
License	BSD-style (see the file LICENSE)
Maintainer	libraries@haskell.org
Stability	stable
Portability	portable
Safe Haskell	Safe
Language	Haskell2010

Data.Functor.Classes

Contents

Liftings of Prelude classes
- For unary constructors
- For binary constructors
Helper functions
- Obsolete helpers

Description

Liftings of the Prelude classes Eq, Ord, Read and Show to unary and binary type constructors.

These classes are needed to express the constraints on arguments of transformers in portable Haskell. Thus for a new transformer T, one might write instances like

instance (Eq1 f) => Eq1 (T f) where ...
instance (Ord1 f) => Ord1 (T f) where ...
instance (Read1 f) => Read1 (T f) where ...
instance (Show1 f) => Show1 (T f) where ...

If these instances can be defined, defining instances of the base classes is mechanical:

instance (Eq1 f, Eq a) => Eq (T f a) where (==) = eq1
instance (Ord1 f, Ord a) => Ord (T f a) where compare = compare1
instance (Read1 f, Read a) => Read (T f a) where
  readPrec     = readPrec1
  readListPrec = readListPrecDefault
instance (Show1 f, Show a) => Show (T f a) where showsPrec = showsPrec1

Since: base-4.9.0.0

Synopsis

class (forall a. Eq a => Eq (f a)) => Eq1 (f :: Type -> Type) where
- liftEq :: (a -> b -> Bool) -> f a -> f b -> Bool
eq1 :: (Eq1 f, Eq a) => f a -> f a -> Bool
class (Eq1 f, forall a. Ord a => Ord (f a)) => Ord1 (f :: Type -> Type) where
- liftCompare :: (a -> b -> Ordering) -> f a -> f b -> Ordering
compare1 :: (Ord1 f, Ord a) => f a -> f a -> Ordering
class (forall a. Read a => Read (f a)) => Read1 (f :: Type -> Type) where
- liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (f a)
- liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [f a]
- liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (f a)
- liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [f a]
readsPrec1 :: (Read1 f, Read a) => Int -> ReadS (f a)
readPrec1 :: (Read1 f, Read a) => ReadPrec (f a)
liftReadListDefault :: Read1 f => (Int -> ReadS a) -> ReadS [a] -> ReadS [f a]
liftReadListPrecDefault :: Read1 f => ReadPrec a -> ReadPrec [a] -> ReadPrec [f a]
class (forall a. Show a => Show (f a)) => Show1 (f :: Type -> Type) where
- liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> f a -> ShowS
- liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [f a] -> ShowS
showsPrec1 :: (Show1 f, Show a) => Int -> f a -> ShowS
class (forall a. Eq a => Eq1 (f a)) => Eq2 (f :: Type -> Type -> Type) where
- liftEq2 :: (a -> b -> Bool) -> (c -> d -> Bool) -> f a c -> f b d -> Bool
eq2 :: (Eq2 f, Eq a, Eq b) => f a b -> f a b -> Bool
class (Eq2 f, forall a. Ord a => Ord1 (f a)) => Ord2 (f :: Type -> Type -> Type) where
- liftCompare2 :: (a -> b -> Ordering) -> (c -> d -> Ordering) -> f a c -> f b d -> Ordering
compare2 :: (Ord2 f, Ord a, Ord b) => f a b -> f a b -> Ordering
class (forall a. Read a => Read1 (f a)) => Read2 (f :: Type -> Type -> Type) where
- liftReadsPrec2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> Int -> ReadS (f a b)
- liftReadList2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [f a b]
- liftReadPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec (f a b)
- liftReadListPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [f a b]
readsPrec2 :: (Read2 f, Read a, Read b) => Int -> ReadS (f a b)
readPrec2 :: (Read2 f, Read a, Read b) => ReadPrec (f a b)
liftReadList2Default :: Read2 f => (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [f a b]
liftReadListPrec2Default :: Read2 f => ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [f a b]
class (forall a. Show a => Show1 (f a)) => Show2 (f :: Type -> Type -> Type) where
- liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> f a b -> ShowS
- liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [f a b] -> ShowS
showsPrec2 :: (Show2 f, Show a, Show b) => Int -> f a b -> ShowS
readsData :: (String -> ReadS a) -> Int -> ReadS a
readData :: ReadPrec a -> ReadPrec a
readsUnaryWith :: (Int -> ReadS a) -> String -> (a -> t) -> String -> ReadS t
readUnaryWith :: ReadPrec a -> String -> (a -> t) -> ReadPrec t
readsBinaryWith :: (Int -> ReadS a) -> (Int -> ReadS b) -> String -> (a -> b -> t) -> String -> ReadS t
readBinaryWith :: ReadPrec a -> ReadPrec b -> String -> (a -> b -> t) -> ReadPrec t
showsUnaryWith :: (Int -> a -> ShowS) -> String -> Int -> a -> ShowS
showsBinaryWith :: (Int -> a -> ShowS) -> (Int -> b -> ShowS) -> String -> Int -> a -> b -> ShowS
readsUnary :: Read a => String -> (a -> t) -> String -> ReadS t
readsUnary1 :: (Read1 f, Read a) => String -> (f a -> t) -> String -> ReadS t
readsBinary1 :: (Read1 f, Read1 g, Read a) => String -> (f a -> g a -> t) -> String -> ReadS t
showsUnary :: Show a => String -> Int -> a -> ShowS
showsUnary1 :: (Show1 f, Show a) => String -> Int -> f a -> ShowS
showsBinary1 :: (Show1 f, Show1 g, Show a) => String -> Int -> f a -> g a -> ShowS

Liftings of Prelude classes

For unary constructors

class (forall a. Eq a => Eq (f a)) => Eq1 (f :: Type -> Type) where Source #

Lifting of the Eq class to unary type constructors.

Any instance should be subject to the following law that canonicity is preserved:

liftEq (==) = (==)

This class therefore represents the generalization of Eq by decomposing its main method into a canonical lifting on a canonical inner method, so that the lifting can be reused for other arguments than the canonical one.

Since: base-4.9.0.0

Minimal complete definition

Nothing

Methods

liftEq :: (a -> b -> Bool) -> f a -> f b -> Bool Source #

Lift an equality test through the type constructor.

The function will usually be applied to an equality function, but the more general type ensures that the implementation uses it to compare elements of the first container with elements of the second.

Since: base-4.9.0.0

default liftEq :: forall (f' :: Type -> Type -> Type) c a b. (f ~ f' c, Eq2 f', Eq c) => (a -> b -> Bool) -> f a -> f b -> Bool Source #

Instances

Instances details

Eq1 Complex Source #	`>>>` `eq1 (1 :+ 2) (1 :+ 2)`True `>>>` `eq1 (1 :+ 2) (1 :+ 3)`False Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a -> b -> Bool) -> Complex a -> Complex b -> Bool Source #
Eq1 Identity Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a -> b -> Bool) -> Identity a -> Identity b -> Bool Source #
Eq1 Down Source #	Since: base-4.12.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a -> b -> Bool) -> Down a -> Down b -> Bool Source #
Eq1 NonEmpty Source #	Since: base-4.10.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a -> b -> Bool) -> NonEmpty a -> NonEmpty b -> Bool Source #
Eq1 Maybe Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a -> b -> Bool) -> Maybe a -> Maybe b -> Bool Source #
Eq1 Solo Source #	Since: base-4.15
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a -> b -> Bool) -> (a) -> (b) -> Bool Source #
Eq1 List Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a -> b -> Bool) -> [a] -> [b] -> Bool Source #
Eq a => Eq1 (Either a) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a0 -> b -> Bool) -> Either a a0 -> Either a b -> Bool Source #
Eq1 (Proxy :: Type -> Type) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a -> b -> Bool) -> Proxy a -> Proxy b -> Bool Source #
Eq a => Eq1 (Tuple2 a) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a0 -> b -> Bool) -> (a, a0) -> (a, b) -> Bool Source #
Eq a => Eq1 (Const a :: Type -> Type) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a0 -> b -> Bool) -> Const a a0 -> Const a b -> Bool Source #
(Generic1 f, Eq1 (Rep1 f)) => Eq1 (Generically1 f) Source #	Since: base-4.17.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a -> b -> Bool) -> Generically1 f a -> Generically1 f b -> Bool Source #
(Eq a, Eq b) => Eq1 (Tuple3 a b) Source #	Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a0 -> b0 -> Bool) -> (a, b, a0) -> (a, b, b0) -> Bool Source #
(Eq1 f, Eq1 g) => Eq1 (Product f g) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Product Methods liftEq :: (a -> b -> Bool) -> Product f g a -> Product f g b -> Bool Source #
(Eq1 f, Eq1 g) => Eq1 (Sum f g) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Sum Methods liftEq :: (a -> b -> Bool) -> Sum f g a -> Sum f g b -> Bool Source #
(Eq a, Eq b, Eq c) => Eq1 (Tuple4 a b c) Source #	Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a0 -> b0 -> Bool) -> (a, b, c, a0) -> (a, b, c, b0) -> Bool Source #
(Eq1 f, Eq1 g) => Eq1 (Compose f g) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Compose Methods liftEq :: (a -> b -> Bool) -> Compose f g a -> Compose f g b -> Bool Source #

eq1 :: (Eq1 f, Eq a) => f a -> f a -> Bool Source #

Lift the standard (==) function through the type constructor.

Since: base-4.9.0.0

class (Eq1 f, forall a. Ord a => Ord (f a)) => Ord1 (f :: Type -> Type) where Source #

Lifting of the Ord class to unary type constructors.

Any instance should be subject to the following law that canonicity is preserved:

liftCompare compare = compare

This class therefore represents the generalization of Ord by decomposing its main method into a canonical lifting on a canonical inner method, so that the lifting can be reused for other arguments than the canonical one.

Since: base-4.9.0.0

Minimal complete definition

Nothing

Methods

liftCompare :: (a -> b -> Ordering) -> f a -> f b -> Ordering Source #

Lift a compare function through the type constructor.

The function will usually be applied to a comparison function, but the more general type ensures that the implementation uses it to compare elements of the first container with elements of the second.

Since: base-4.9.0.0

default liftCompare :: forall (f' :: Type -> Type -> Type) c a b. (f ~ f' c, Ord2 f', Ord c) => (a -> b -> Ordering) -> f a -> f b -> Ordering Source #

Instances

Instances details

Ord1 Identity Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a -> b -> Ordering) -> Identity a -> Identity b -> Ordering Source #
Ord1 Down Source #	Since: base-4.12.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a -> b -> Ordering) -> Down a -> Down b -> Ordering Source #
Ord1 NonEmpty Source #	Since: base-4.10.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a -> b -> Ordering) -> NonEmpty a -> NonEmpty b -> Ordering Source #
Ord1 Maybe Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a -> b -> Ordering) -> Maybe a -> Maybe b -> Ordering Source #
Ord1 Solo Source #	Since: base-4.15
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a -> b -> Ordering) -> (a) -> (b) -> Ordering Source #
Ord1 List Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a -> b -> Ordering) -> [a] -> [b] -> Ordering Source #
Ord a => Ord1 (Either a) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a0 -> b -> Ordering) -> Either a a0 -> Either a b -> Ordering Source #
Ord1 (Proxy :: Type -> Type) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a -> b -> Ordering) -> Proxy a -> Proxy b -> Ordering Source #
Ord a => Ord1 (Tuple2 a) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a0 -> b -> Ordering) -> (a, a0) -> (a, b) -> Ordering Source #
Ord a => Ord1 (Const a :: Type -> Type) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a0 -> b -> Ordering) -> Const a a0 -> Const a b -> Ordering Source #
(Generic1 f, Ord1 (Rep1 f)) => Ord1 (Generically1 f) Source #	Since: base-4.17.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a -> b -> Ordering) -> Generically1 f a -> Generically1 f b -> Ordering Source #
(Ord a, Ord b) => Ord1 (Tuple3 a b) Source #	Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a0 -> b0 -> Ordering) -> (a, b, a0) -> (a, b, b0) -> Ordering Source #
(Ord1 f, Ord1 g) => Ord1 (Product f g) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Product Methods liftCompare :: (a -> b -> Ordering) -> Product f g a -> Product f g b -> Ordering Source #
(Ord1 f, Ord1 g) => Ord1 (Sum f g) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Sum Methods liftCompare :: (a -> b -> Ordering) -> Sum f g a -> Sum f g b -> Ordering Source #
(Ord a, Ord b, Ord c) => Ord1 (Tuple4 a b c) Source #	Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a0 -> b0 -> Ordering) -> (a, b, c, a0) -> (a, b, c, b0) -> Ordering Source #
(Ord1 f, Ord1 g) => Ord1 (Compose f g) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Compose Methods liftCompare :: (a -> b -> Ordering) -> Compose f g a -> Compose f g b -> Ordering Source #

compare1 :: (Ord1 f, Ord a) => f a -> f a -> Ordering Source #

Lift the standard compare function through the type constructor.

Since: base-4.9.0.0

class (forall a. Read a => Read (f a)) => Read1 (f :: Type -> Type) where Source #

Lifting of the Read class to unary type constructors.

Any instance should be subject to the following laws that canonicity is preserved:

liftReadsPrec readsPrec readList = readsPrec

liftReadList readsPrec readList = readList

liftReadPrec readPrec readListPrec = readPrec

liftReadListPrec readPrec readListPrec = readListPrec

This class therefore represents the generalization of Read by decomposing it's methods into a canonical lifting on a canonical inner method, so that the lifting can be reused for other arguments than the canonical one.

Both liftReadsPrec and liftReadPrec exist to match the interface provided in the Read type class, but it is recommended to implement Read1 instances using liftReadPrec as opposed to liftReadsPrec, since the former is more efficient than the latter. For example:

instance Read1 T where
  liftReadPrec     = ...
  liftReadListPrec = liftReadListPrecDefault

For more information, refer to the documentation for the Read class.

Since: base-4.9.0.0

Minimal complete definition

liftReadsPrec | liftReadPrec

Methods

liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (f a) Source #

readsPrec function for an application of the type constructor based on readsPrec and readList functions for the argument type.

Since: base-4.9.0.0

liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [f a] Source #

readList function for an application of the type constructor based on readsPrec and readList functions for the argument type. The default implementation using standard list syntax is correct for most types.

Since: base-4.9.0.0

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (f a) Source #

readPrec function for an application of the type constructor based on readPrec and readListPrec functions for the argument type.

Since: base-4.10.0.0

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [f a] Source #

readListPrec function for an application of the type constructor based on readPrec and readListPrec functions for the argument type.

The default definition uses liftReadList. Instances that define liftReadPrec should also define liftReadListPrec as liftReadListPrecDefault.

Since: base-4.10.0.0

Instances

Instances details

Read1 Complex Source #	`>>>` `readPrec_to_S readPrec1 0 "(2 % 3) :+ (3 % 4)" :: [(Complex Rational, String)]`[(2 % 3 :+ 3 % 4,"")] Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Complex a) Source # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Complex a] Source # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Complex a) Source # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Complex a] Source #
Read1 Identity Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Identity a) Source # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Identity a] Source # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Identity a) Source # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Identity a] Source #
Read1 Down Source #	Since: base-4.12.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Down a) Source # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Down a] Source # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Down a) Source # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Down a] Source #
Read1 NonEmpty Source #	Since: base-4.10.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (NonEmpty a) Source # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [NonEmpty a] Source # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (NonEmpty a) Source # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [NonEmpty a] Source #
Read1 Maybe Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Maybe a) Source # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Maybe a] Source # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Maybe a) Source # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Maybe a] Source #
Read1 Solo Source #	Since: base-4.15
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (a) Source # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [(a)] Source # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (a) Source # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [(a)] Source #
Read1 List Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS [a] Source # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [[a]] Source # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [a] Source # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [[a]] Source #
Read a => Read1 (Either a) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a0) -> ReadS [a0] -> Int -> ReadS (Either a a0) Source # liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [Either a a0] Source # liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (Either a a0) Source # liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [Either a a0] Source #
Read1 (Proxy :: Type -> Type) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Proxy a) Source # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Proxy a] Source # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Proxy a) Source # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Proxy a] Source #
Read a => Read1 (Tuple2 a) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a0) -> ReadS [a0] -> Int -> ReadS (a, a0) Source # liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [(a, a0)] Source # liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (a, a0) Source # liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [(a, a0)] Source #
Read a => Read1 (Const a :: Type -> Type) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a0) -> ReadS [a0] -> Int -> ReadS (Const a a0) Source # liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [Const a a0] Source # liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (Const a a0) Source # liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [Const a a0] Source #
(Read a, Read b) => Read1 (Tuple3 a b) Source #	Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a0) -> ReadS [a0] -> Int -> ReadS (a, b, a0) Source # liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [(a, b, a0)] Source # liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (a, b, a0) Source # liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [(a, b, a0)] Source #
(Read1 f, Read1 g) => Read1 (Product f g) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Product Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Product f g a) Source # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Product f g a] Source # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Product f g a) Source # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Product f g a] Source #
(Read1 f, Read1 g) => Read1 (Sum f g) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Sum Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Sum f g a) Source # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Sum f g a] Source # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Sum f g a) Source # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Sum f g a] Source #
(Read a, Read b, Read c) => Read1 (Tuple4 a b c) Source #	Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a0) -> ReadS [a0] -> Int -> ReadS (a, b, c, a0) Source # liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [(a, b, c, a0)] Source # liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (a, b, c, a0) Source # liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [(a, b, c, a0)] Source #
(Read1 f, Read1 g) => Read1 (Compose f g) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Compose Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Compose f g a) Source # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Compose f g a] Source # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Compose f g a) Source # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Compose f g a] Source #

readsPrec1 :: (Read1 f, Read a) => Int -> ReadS (f a) Source #

Lift the standard readsPrec and readList functions through the type constructor.

Since: base-4.9.0.0

readPrec1 :: (Read1 f, Read a) => ReadPrec (f a) Source #

Lift the standard readPrec and readListPrec functions through the type constructor.

Since: base-4.10.0.0

liftReadListDefault :: Read1 f => (Int -> ReadS a) -> ReadS [a] -> ReadS [f a] Source #

A possible replacement definition for the liftReadList method. This is only needed for Read1 instances where liftReadListPrec isn't defined as liftReadListPrecDefault.

Since: base-4.10.0.0

liftReadListPrecDefault :: Read1 f => ReadPrec a -> ReadPrec [a] -> ReadPrec [f a] Source #

A possible replacement definition for the liftReadListPrec method, defined using liftReadPrec.

Since: base-4.10.0.0

class (forall a. Show a => Show (f a)) => Show1 (f :: Type -> Type) where Source #

Lifting of the Show class to unary type constructors.

Any instance should be subject to the following laws that canonicity is preserved:

liftShowsPrec showsPrec showList = showsPrec

liftShowList showsPrec showList = showList

This class therefore represents the generalization of Show by decomposing it's methods into a canonical lifting on a canonical inner method, so that the lifting can be reused for other arguments than the canonical one.

Since: base-4.9.0.0

Minimal complete definition

Nothing

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> f a -> ShowS Source #

showsPrec function for an application of the type constructor based on showsPrec and showList functions for the argument type.

Since: base-4.9.0.0

default liftShowsPrec :: forall (f' :: Type -> Type -> Type) b a. (f ~ f' b, Show2 f', Show b) => (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> f a -> ShowS Source #

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [f a] -> ShowS Source #

showList function for an application of the type constructor based on showsPrec and showList functions for the argument type. The default implementation using standard list syntax is correct for most types.

Since: base-4.9.0.0

Instances

Instances details

Show1 Complex Source #	`>>>` `showsPrec1 0 (2 :+ 3) ""`"2 :+ 3" Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Complex a -> ShowS Source # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Complex a] -> ShowS Source #
Show1 Identity Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Identity a -> ShowS Source # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Identity a] -> ShowS Source #
Show1 Down Source #	Since: base-4.12.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Down a -> ShowS Source # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Down a] -> ShowS Source #
Show1 NonEmpty Source #	Since: base-4.10.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> NonEmpty a -> ShowS Source # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [NonEmpty a] -> ShowS Source #
Show1 Maybe Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Maybe a -> ShowS Source # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Maybe a] -> ShowS Source #
Show1 Solo Source #	Since: base-4.15
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> (a) -> ShowS Source # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [(a)] -> ShowS Source #
Show1 List Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> [a] -> ShowS Source # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [[a]] -> ShowS Source #
Show a => Show1 (Either a) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> Int -> Either a a0 -> ShowS Source # liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [Either a a0] -> ShowS Source #
Show1 (Proxy :: Type -> Type) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Proxy a -> ShowS Source # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Proxy a] -> ShowS Source #
Show a => Show1 (Tuple2 a) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> Int -> (a, a0) -> ShowS Source # liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [(a, a0)] -> ShowS Source #
Show a => Show1 (Const a :: Type -> Type) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> Int -> Const a a0 -> ShowS Source # liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [Const a a0] -> ShowS Source #
(Show a, Show b) => Show1 (Tuple3 a b) Source #	Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> Int -> (a, b, a0) -> ShowS Source # liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [(a, b, a0)] -> ShowS Source #
(Show1 f, Show1 g) => Show1 (Product f g) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Product Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Product f g a -> ShowS Source # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Product f g a] -> ShowS Source #
(Show1 f, Show1 g) => Show1 (Sum f g) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Sum Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Sum f g a -> ShowS Source # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Sum f g a] -> ShowS Source #
(Show a, Show b, Show c) => Show1 (Tuple4 a b c) Source #	Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> Int -> (a, b, c, a0) -> ShowS Source # liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [(a, b, c, a0)] -> ShowS Source #
(Show1 f, Show1 g) => Show1 (Compose f g) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Compose Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Compose f g a -> ShowS Source # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Compose f g a] -> ShowS Source #

showsPrec1 :: (Show1 f, Show a) => Int -> f a -> ShowS Source #

Lift the standard showsPrec and showList functions through the type constructor.

Since: base-4.9.0.0

For binary constructors

class (forall a. Eq a => Eq1 (f a)) => Eq2 (f :: Type -> Type -> Type) where Source #

Lifting of the Eq class to binary type constructors.

Since: base-4.9.0.0

Methods

liftEq2 :: (a -> b -> Bool) -> (c -> d -> Bool) -> f a c -> f b d -> Bool Source #

Lift equality tests through the type constructor.

The function will usually be applied to equality functions, but the more general type ensures that the implementation uses them to compare elements of the first container with elements of the second.

Since: base-4.9.0.0

Instances

Instances details

Eq2 Either Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq2 :: (a -> b -> Bool) -> (c -> d -> Bool) -> Either a c -> Either b d -> Bool Source #
Eq2 Tuple2 Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq2 :: (a -> b -> Bool) -> (c -> d -> Bool) -> (a, c) -> (b, d) -> Bool Source #
Eq2 (Const :: Type -> Type -> Type) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq2 :: (a -> b -> Bool) -> (c -> d -> Bool) -> Const a c -> Const b d -> Bool Source #
Eq a => Eq2 (Tuple3 a) Source #	`>>>` `eq2 ('x', True, "str") ('x', True, "str")`True Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq2 :: (a0 -> b -> Bool) -> (c -> d -> Bool) -> (a, a0, c) -> (a, b, d) -> Bool Source #
(Eq a, Eq b) => Eq2 (Tuple4 a b) Source #	`>>>` `eq2 ('x', True, "str", 2) ('x', True, "str", 2 :: Int)`True Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq2 :: (a0 -> b0 -> Bool) -> (c -> d -> Bool) -> (a, b, a0, c) -> (a, b, b0, d) -> Bool Source #

eq2 :: (Eq2 f, Eq a, Eq b) => f a b -> f a b -> Bool Source #

Lift the standard (==) function through the type constructor.

Since: base-4.9.0.0

class (Eq2 f, forall a. Ord a => Ord1 (f a)) => Ord2 (f :: Type -> Type -> Type) where Source #

Lifting of the Ord class to binary type constructors.

Since: base-4.9.0.0

Methods

liftCompare2 :: (a -> b -> Ordering) -> (c -> d -> Ordering) -> f a c -> f b d -> Ordering Source #

Lift compare functions through the type constructor.

The function will usually be applied to comparison functions, but the more general type ensures that the implementation uses them to compare elements of the first container with elements of the second.

Since: base-4.9.0.0

Instances

Instances details

Ord2 Either Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare2 :: (a -> b -> Ordering) -> (c -> d -> Ordering) -> Either a c -> Either b d -> Ordering Source #
Ord2 Tuple2 Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare2 :: (a -> b -> Ordering) -> (c -> d -> Ordering) -> (a, c) -> (b, d) -> Ordering Source #
Ord2 (Const :: Type -> Type -> Type) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare2 :: (a -> b -> Ordering) -> (c -> d -> Ordering) -> Const a c -> Const b d -> Ordering Source #
Ord a => Ord2 (Tuple3 a) Source #	`>>>` `compare2 ('x', True, "aaa") ('x', True, "zzz")`LT Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare2 :: (a0 -> b -> Ordering) -> (c -> d -> Ordering) -> (a, a0, c) -> (a, b, d) -> Ordering Source #
(Ord a, Ord b) => Ord2 (Tuple4 a b) Source #	`>>>` `compare2 ('x', True, "str", 2) ('x', True, "str", 3 :: Int)`LT Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare2 :: (a0 -> b0 -> Ordering) -> (c -> d -> Ordering) -> (a, b, a0, c) -> (a, b, b0, d) -> Ordering Source #

compare2 :: (Ord2 f, Ord a, Ord b) => f a b -> f a b -> Ordering Source #

Lift the standard compare function through the type constructor.

Since: base-4.9.0.0

class (forall a. Read a => Read1 (f a)) => Read2 (f :: Type -> Type -> Type) where Source #

Lifting of the Read class to binary type constructors.

Both liftReadsPrec2 and liftReadPrec2 exist to match the interface provided in the Read type class, but it is recommended to implement Read2 instances using liftReadPrec2 as opposed to liftReadsPrec2, since the former is more efficient than the latter. For example:

instance Read2 T where
  liftReadPrec2     = ...
  liftReadListPrec2 = liftReadListPrec2Default

For more information, refer to the documentation for the Read class.

Since: base-4.9.0.0

Minimal complete definition

liftReadsPrec2 | liftReadPrec2

Methods

liftReadsPrec2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> Int -> ReadS (f a b) Source #

readsPrec function for an application of the type constructor based on readsPrec and readList functions for the argument types.

Since: base-4.9.0.0

liftReadList2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [f a b] Source #

readList function for an application of the type constructor based on readsPrec and readList functions for the argument types. The default implementation using standard list syntax is correct for most types.

Since: base-4.9.0.0

liftReadPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec (f a b) Source #

readPrec function for an application of the type constructor based on readPrec and readListPrec functions for the argument types.

Since: base-4.10.0.0

liftReadListPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [f a b] Source #

readListPrec function for an application of the type constructor based on readPrec and readListPrec functions for the argument types.

The default definition uses liftReadList2. Instances that define liftReadPrec2 should also define liftReadListPrec2 as liftReadListPrec2Default.

Since: base-4.10.0.0

Instances

Instances details

Read2 Either Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> Int -> ReadS (Either a b) Source # liftReadList2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [Either a b] Source # liftReadPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec (Either a b) Source # liftReadListPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [Either a b] Source #
Read2 Tuple2 Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> Int -> ReadS (a, b) Source # liftReadList2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [(a, b)] Source # liftReadPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec (a, b) Source # liftReadListPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [(a, b)] Source #
Read2 (Const :: Type -> Type -> Type) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> Int -> ReadS (Const a b) Source # liftReadList2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [Const a b] Source # liftReadPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec (Const a b) Source # liftReadListPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [Const a b] Source #
Read a => Read2 (Tuple3 a) Source #	`>>>` `readPrec_to_S readPrec2 0 "('x', True, 2)" :: [((Char, Bool, Int), String)]`[(('x',True,2),"")] Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec2 :: (Int -> ReadS a0) -> ReadS [a0] -> (Int -> ReadS b) -> ReadS [b] -> Int -> ReadS (a, a0, b) Source # liftReadList2 :: (Int -> ReadS a0) -> ReadS [a0] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [(a, a0, b)] Source # liftReadPrec2 :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec b -> ReadPrec [b] -> ReadPrec (a, a0, b) Source # liftReadListPrec2 :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [(a, a0, b)] Source #
(Read a, Read b) => Read2 (Tuple4 a b) Source #	`>>>` `readPrec_to_S readPrec2 0 "('x', True, 2, 4.5)" :: [((Char, Bool, Int, Double), String)]`[(('x',True,2,4.5),"")] Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec2 :: (Int -> ReadS a0) -> ReadS [a0] -> (Int -> ReadS b0) -> ReadS [b0] -> Int -> ReadS (a, b, a0, b0) Source # liftReadList2 :: (Int -> ReadS a0) -> ReadS [a0] -> (Int -> ReadS b0) -> ReadS [b0] -> ReadS [(a, b, a0, b0)] Source # liftReadPrec2 :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec b0 -> ReadPrec [b0] -> ReadPrec (a, b, a0, b0) Source # liftReadListPrec2 :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec b0 -> ReadPrec [b0] -> ReadPrec [(a, b, a0, b0)] Source #

readsPrec2 :: (Read2 f, Read a, Read b) => Int -> ReadS (f a b) Source #

Lift the standard readsPrec function through the type constructor.

Since: base-4.9.0.0

readPrec2 :: (Read2 f, Read a, Read b) => ReadPrec (f a b) Source #

Lift the standard readPrec function through the type constructor.

Since: base-4.10.0.0

liftReadList2Default :: Read2 f => (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [f a b] Source #

A possible replacement definition for the liftReadList2 method. This is only needed for Read2 instances where liftReadListPrec2 isn't defined as liftReadListPrec2Default.

Since: base-4.10.0.0

liftReadListPrec2Default :: Read2 f => ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [f a b] Source #

A possible replacement definition for the liftReadListPrec2 method, defined using liftReadPrec2.

Since: base-4.10.0.0

class (forall a. Show a => Show1 (f a)) => Show2 (f :: Type -> Type -> Type) where Source #

Lifting of the Show class to binary type constructors.

Since: base-4.9.0.0

Minimal complete definition

liftShowsPrec2

Methods

liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> f a b -> ShowS Source #

showsPrec function for an application of the type constructor based on showsPrec and showList functions for the argument types.

Since: base-4.9.0.0

liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [f a b] -> ShowS Source #

showList function for an application of the type constructor based on showsPrec and showList functions for the argument types. The default implementation using standard list syntax is correct for most types.

Since: base-4.9.0.0

Instances

Instances details

Show2 Either Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> Either a b -> ShowS Source # liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [Either a b] -> ShowS Source #
Show2 Tuple2 Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> (a, b) -> ShowS Source # liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [(a, b)] -> ShowS Source #
Show2 (Const :: Type -> Type -> Type) Source #	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> Const a b -> ShowS Source # liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [Const a b] -> ShowS Source #
Show a => Show2 (Tuple3 a) Source #	`>>>` `showsPrec2 0 ('x', True, 2 :: Int) ""`"('x',True,2)" Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec2 :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> (a, a0, b) -> ShowS Source # liftShowList2 :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [(a, a0, b)] -> ShowS Source #
(Show a, Show b) => Show2 (Tuple4 a b) Source #	`>>>` `showsPrec2 0 ('x', True, 2 :: Int, 4.5 :: Double) ""`"('x',True,2,4.5)" Since: base-4.16.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec2 :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> (Int -> b0 -> ShowS) -> ([b0] -> ShowS) -> Int -> (a, b, a0, b0) -> ShowS Source # liftShowList2 :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> (Int -> b0 -> ShowS) -> ([b0] -> ShowS) -> [(a, b, a0, b0)] -> ShowS Source #

showsPrec2 :: (Show2 f, Show a, Show b) => Int -> f a b -> ShowS Source #

Lift the standard showsPrec function through the type constructor.

Since: base-4.9.0.0

Helper functions

These functions can be used to assemble Read and Show instances for new algebraic types. For example, given the definition

data T f a = Zero a | One (f a) | Two a (f a)

a standard Read1 instance may be defined as

instance (Read1 f) => Read1 (T f) where
    liftReadPrec rp rl = readData $
        readUnaryWith rp "Zero" Zero <|>
        readUnaryWith (liftReadPrec rp rl) "One" One <|>
        readBinaryWith rp (liftReadPrec rp rl) "Two" Two
    liftReadListPrec = liftReadListPrecDefault

and the corresponding Show1 instance as

instance (Show1 f) => Show1 (T f) where
    liftShowsPrec sp _ d (Zero x) =
        showsUnaryWith sp "Zero" d x
    liftShowsPrec sp sl d (One x) =
        showsUnaryWith (liftShowsPrec sp sl) "One" d x
    liftShowsPrec sp sl d (Two x y) =
        showsBinaryWith sp (liftShowsPrec sp sl) "Two" d x y

readsData :: (String -> ReadS a) -> Int -> ReadS a Source #

readsData p d is a parser for datatypes where each alternative begins with a data constructor. It parses the constructor and passes it to p. Parsers for various constructors can be constructed with readsUnary, readsUnary1 and readsBinary1, and combined with mappend from the Monoid class.

Since: base-4.9.0.0

readData :: ReadPrec a -> ReadPrec a Source #

readData p is a parser for datatypes where each alternative begins with a data constructor. It parses the constructor and passes it to p. Parsers for various constructors can be constructed with readUnaryWith and readBinaryWith, and combined with (<|>) from the Alternative class.

Since: base-4.10.0.0

readsUnaryWith :: (Int -> ReadS a) -> String -> (a -> t) -> String -> ReadS t Source #

readsUnaryWith rp n c n' matches the name of a unary data constructor and then parses its argument using rp.

Since: base-4.9.0.0

readUnaryWith :: ReadPrec a -> String -> (a -> t) -> ReadPrec t Source #

readUnaryWith rp n c' matches the name of a unary data constructor and then parses its argument using rp.

Since: base-4.10.0.0

readsBinaryWith :: (Int -> ReadS a) -> (Int -> ReadS b) -> String -> (a -> b -> t) -> String -> ReadS t Source #

readsBinaryWith rp1 rp2 n c n' matches the name of a binary data constructor and then parses its arguments using rp1 and rp2 respectively.

Since: base-4.9.0.0

readBinaryWith :: ReadPrec a -> ReadPrec b -> String -> (a -> b -> t) -> ReadPrec t Source #

readBinaryWith rp1 rp2 n c' matches the name of a binary data constructor and then parses its arguments using rp1 and rp2 respectively.

Since: base-4.10.0.0

showsUnaryWith :: (Int -> a -> ShowS) -> String -> Int -> a -> ShowS Source #

showsUnaryWith sp n d x produces the string representation of a unary data constructor with name n and argument x, in precedence context d.

Since: base-4.9.0.0

showsBinaryWith :: (Int -> a -> ShowS) -> (Int -> b -> ShowS) -> String -> Int -> a -> b -> ShowS Source #

showsBinaryWith sp1 sp2 n d x y produces the string representation of a binary data constructor with name n and arguments x and y, in precedence context d.

Since: base-4.9.0.0

Obsolete helpers

readsUnary :: Read a => String -> (a -> t) -> String -> ReadS t Source #

Deprecated: Use readsUnaryWith to define liftReadsPrec

readsUnary n c n' matches the name of a unary data constructor and then parses its argument using readsPrec.

Since: base-4.9.0.0

readsUnary1 :: (Read1 f, Read a) => String -> (f a -> t) -> String -> ReadS t Source #

Deprecated: Use readsUnaryWith to define liftReadsPrec

readsUnary1 n c n' matches the name of a unary data constructor and then parses its argument using readsPrec1.

Since: base-4.9.0.0

readsBinary1 :: (Read1 f, Read1 g, Read a) => String -> (f a -> g a -> t) -> String -> ReadS t Source #

Deprecated: Use readsBinaryWith to define liftReadsPrec

readsBinary1 n c n' matches the name of a binary data constructor and then parses its arguments using readsPrec1.

Since: base-4.9.0.0

showsUnary :: Show a => String -> Int -> a -> ShowS Source #

Deprecated: Use showsUnaryWith to define liftShowsPrec

showsUnary n d x produces the string representation of a unary data constructor with name n and argument x, in precedence context d.

Since: base-4.9.0.0

showsUnary1 :: (Show1 f, Show a) => String -> Int -> f a -> ShowS Source #

Deprecated: Use showsUnaryWith to define liftShowsPrec

showsUnary1 n d x produces the string representation of a unary data constructor with name n and argument x, in precedence context d.

Since: base-4.9.0.0

showsBinary1 :: (Show1 f, Show1 g, Show a) => String -> Int -> f a -> g a -> ShowS Source #

Deprecated: Use showsBinaryWith to define liftShowsPrec

showsBinary1 n d x y produces the string representation of a binary data constructor with name n and arguments x and y, in precedence context d.

Since: base-4.9.0.0