auto-lift-classes-1.1: Deriving (Show|Read)(1|2)
Safe HaskellSafe-Inferred
LanguageHaskell2010

AutoLift.Coercible

Contents

Description

Derive lifted version of Show or Read classes, like Show1 f or Read1 f, from derivable instance forall a. Show a => Show (f a).

Synopsis

Documentation

newtype Reflected1 f a Source #

A newtype wrapper to derive Show1 f and Read1 f from the following, often derivable instance.

instance Show a => Show (f a)
instance Read a => Read (f a)

Example

Suppose you define a new type constructor Foo, and derived its Show instance.

>>> data Foo a = Foo [a] Int a deriving Show

The derived Show (Foo a) instance is defined for all a with Show a instance.

instance Show a => Show (Foo a)

Reflected1 allows you to derive Show1 Foo instance from the above instance.

>>> :set -XStandaloneDeriving -XDerivingVia
>>> deriving via (Reflected1 Foo) instance Show1 Foo

Let's try the derived Show1 instance, by showing Foo Bool, where True is shown as yes and False as no, instead of the normal Show Bool instance.

>>> import Text.Show (showListWith)
>>> let yesno b = (++) (if b then "yes" else "no")
>>> liftShowsPrec (const yesno) (showListWith yesno) 0 (Foo [True, False] 5 False) ""
"Foo [yes,no] 5 no"

Constructors

Reflected1 (f a) 

Instances

Instances details
(forall a. Read a => Read (f a), forall xx yy. Coercible xx yy => Coercible (f xx) (f yy)) => Read1 (Reflected1 f) Source # 
Instance details

Defined in AutoLift.Coercible

Methods

liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Reflected1 f a) #

liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Reflected1 f a] #

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Reflected1 f a) #

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Reflected1 f a] #

(forall a. Show a => Show (f a), forall xx yy. Coercible xx yy => Coercible (f xx) (f yy)) => Show1 (Reflected1 f) Source # 
Instance details

Defined in AutoLift.Coercible

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Reflected1 f a -> ShowS #

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Reflected1 f a] -> ShowS #

Read (f a) => Read (Reflected1 f a) Source # 
Instance details

Defined in AutoLift.Coercible

Show (f a) => Show (Reflected1 f a) Source # 
Instance details

Defined in AutoLift.Coercible

Methods

showsPrec :: Int -> Reflected1 f a -> ShowS #

show :: Reflected1 f a -> String #

showList :: [Reflected1 f a] -> ShowS #

newtype Reflected2 f a b Source #

A newtype wrapper to derive Show2 f and Read2 f from the following, often derivable instance.

instance (Show a, Show b) => Show (f a b)
instance (Read a, Read b) => Read (f a b)

Example

Suppose you define a new type constructor Bar, and derived its Show instance.

>>> data Bar a b = Bar [(Int,a,b)] deriving Show

The derived Show (Bar a b) instance is defined for all a and b with Show instances.

instance (Show a, Show b) => Show (Bar a b)

Reflected2 allows you to derive Show2 Bar instance from the above instance.

>>> :set -XStandaloneDeriving -XDerivingVia
>>> deriving via (Reflected2 Bar) instance Show2 Bar

Let's try the derived Show2 instance by showing Bar Bool Char, where True is shown as yes and False as no, instead of the normal Show Bool instance.

>>> import Text.Show (showListWith)
>>> let yesno b = (++) (if b then "yes" else "no")
>>> liftShowsPrec2 (const yesno) (showListWith yesno) showsPrec showList 0 (Bar [(1, True, 'A'), (2, False, 'B')]) ""
"Bar [(1,yes,'A'),(2,no,'B')]"

Constructors

Reflected2 (f a b) 

Instances

Instances details
(forall a b. (Read a, Read b) => Read (f a b), forall x1 y1 x2 y2. (Coercible x1 y1, Coercible x2 y2) => Coercible (f x1 x2) (f y1 y2)) => Read2 (Reflected2 f) Source # 
Instance details

Defined in AutoLift.Coercible

Methods

liftReadsPrec2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> Int -> ReadS (Reflected2 f a b) #

liftReadList2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [Reflected2 f a b] #

liftReadPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec (Reflected2 f a b) #

liftReadListPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [Reflected2 f a b] #

(forall a b. (Show a, Show b) => Show (f a b), forall x1 y1 x2 y2. (Coercible x1 y1, Coercible x2 y2) => Coercible (f x1 x2) (f y1 y2)) => Show2 (Reflected2 f) Source # 
Instance details

Defined in AutoLift.Coercible

Methods

liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> Reflected2 f a b -> ShowS #

liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [Reflected2 f a b] -> ShowS #

(forall y. Read y => Read (f a y), forall x y. Coercible x y => Coercible (f a x) (f a y)) => Read1 (Reflected2 f a) Source # 
Instance details

Defined in AutoLift.Coercible

Methods

liftReadsPrec :: (Int -> ReadS a0) -> ReadS [a0] -> Int -> ReadS (Reflected2 f a a0) #

liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [Reflected2 f a a0] #

liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (Reflected2 f a a0) #

liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [Reflected2 f a a0] #

(forall y. Show y => Show (f a y), forall x y. Coercible x y => Coercible (f a x) (f a y)) => Show1 (Reflected2 f a) Source # 
Instance details

Defined in AutoLift.Coercible

Methods

liftShowsPrec :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> Int -> Reflected2 f a a0 -> ShowS #

liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [Reflected2 f a a0] -> ShowS #

Read (f a b) => Read (Reflected2 f a b) Source # 
Instance details

Defined in AutoLift.Coercible

Show (f a b) => Show (Reflected2 f a b) Source # 
Instance details

Defined in AutoLift.Coercible

Methods

showsPrec :: Int -> Reflected2 f a b -> ShowS #

show :: Reflected2 f a b -> String #

showList :: [Reflected2 f a b] -> ShowS #

Reexports

class Show1 (f :: TYPE LiftedRep -> TYPE LiftedRep) where #

Lifting of the Show class to unary type constructors.

Since: base-4.9.0.0

Minimal complete definition

liftShowsPrec

Methods

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

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

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

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
>>> 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 #

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

Show1 Identity

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

Show1 Down

Since: base-4.12.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

Show1 NonEmpty

Since: base-4.10.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

Show1 Maybe

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

Show1 Solo

Since: base-4.15

Instance details

Defined in Data.Functor.Classes

Methods

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

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

Show1 []

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

(forall a. Show a => Show (f a), forall xx yy. Coercible xx yy => Coercible (f xx) (f yy)) => Show1 (Reflected1 f) Source # 
Instance details

Defined in AutoLift.Coercible

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Reflected1 f a -> ShowS #

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Reflected1 f a] -> ShowS #

(forall a. Show a => Show (f a), Functor f) => Show1 (Reflected1 f) Source # 
Instance details

Defined in AutoLift.Functor

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Reflected1 f a -> ShowS #

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Reflected1 f a] -> ShowS #

Show a => Show1 (Either a)

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 #

liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [Either a a0] -> ShowS #

Show1 (Proxy :: TYPE LiftedRep -> Type)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

Show a => Show1 ((,) a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftShowsPrec :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> Int -> (a, a0) -> ShowS #

liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [(a, a0)] -> ShowS #

(forall y. Show y => Show (f a y), forall x y. Coercible x y => Coercible (f a x) (f a y)) => Show1 (Reflected2 f a) Source # 
Instance details

Defined in AutoLift.Coercible

Methods

liftShowsPrec :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> Int -> Reflected2 f a a0 -> ShowS #

liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [Reflected2 f a a0] -> ShowS #

(forall y. Show y => Show (f a y), Functor (f a)) => Show1 (Reflected2 f a) Source # 
Instance details

Defined in AutoLift.Functor

Methods

liftShowsPrec :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> Int -> Reflected2 f a a0 -> ShowS #

liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [Reflected2 f a a0] -> ShowS #

Show a => Show1 (Const a :: TYPE LiftedRep -> Type)

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 #

liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [Const a a0] -> ShowS #

(Show a, Show b) => Show1 ((,,) a b)

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 #

liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [(a, b, a0)] -> ShowS #

(Show a, Show b, Show c) => Show1 ((,,,) a b c)

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 #

liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [(a, b, c, a0)] -> ShowS #

class Read a where #

Parsing of Strings, producing values.

Derived instances of Read make the following assumptions, which derived instances of Show obey:

  • If the constructor is defined to be an infix operator, then the derived Read instance will parse only infix applications of the constructor (not the prefix form).
  • Associativity is not used to reduce the occurrence of parentheses, although precedence may be.
  • If the constructor is defined using record syntax, the derived Read will parse only the record-syntax form, and furthermore, the fields must be given in the same order as the original declaration.
  • The derived Read instance allows arbitrary Haskell whitespace between tokens of the input string. Extra parentheses are also allowed.

For example, given the declarations

infixr 5 :^:
data Tree a =  Leaf a  |  Tree a :^: Tree a

the derived instance of Read in Haskell 2010 is equivalent to

instance (Read a) => Read (Tree a) where

        readsPrec d r =  readParen (d > app_prec)
                         (\r -> [(Leaf m,t) |
                                 ("Leaf",s) <- lex r,
                                 (m,t) <- readsPrec (app_prec+1) s]) r

                      ++ readParen (d > up_prec)
                         (\r -> [(u:^:v,w) |
                                 (u,s) <- readsPrec (up_prec+1) r,
                                 (":^:",t) <- lex s,
                                 (v,w) <- readsPrec (up_prec+1) t]) r

          where app_prec = 10
                up_prec = 5

Note that right-associativity of :^: is unused.

The derived instance in GHC is equivalent to

instance (Read a) => Read (Tree a) where

        readPrec = parens $ (prec app_prec $ do
                                 Ident "Leaf" <- lexP
                                 m <- step readPrec
                                 return (Leaf m))

                     +++ (prec up_prec $ do
                                 u <- step readPrec
                                 Symbol ":^:" <- lexP
                                 v <- step readPrec
                                 return (u :^: v))

          where app_prec = 10
                up_prec = 5

        readListPrec = readListPrecDefault

Why do both readsPrec and readPrec exist, and why does GHC opt to implement readPrec in derived Read instances instead of readsPrec? The reason is that readsPrec is based on the ReadS type, and although ReadS is mentioned in the Haskell 2010 Report, it is not a very efficient parser data structure.

readPrec, on the other hand, is based on a much more efficient ReadPrec datatype (a.k.a "new-style parsers"), but its definition relies on the use of the RankNTypes language extension. Therefore, readPrec (and its cousin, readListPrec) are marked as GHC-only. Nevertheless, it is recommended to use readPrec instead of readsPrec whenever possible for the efficiency improvements it brings.

As mentioned above, derived Read instances in GHC will implement readPrec instead of readsPrec. The default implementations of readsPrec (and its cousin, readList) will simply use readPrec under the hood. If you are writing a Read instance by hand, it is recommended to write it like so:

instance Read T where
  readPrec     = ...
  readListPrec = readListPrecDefault

Minimal complete definition

readsPrec | readPrec

Methods

readsPrec #

Arguments

:: Int

the operator precedence of the enclosing context (a number from 0 to 11). Function application has precedence 10.

-> ReadS a 

attempts to parse a value from the front of the string, returning a list of (parsed value, remaining string) pairs. If there is no successful parse, the returned list is empty.

Derived instances of Read and Show satisfy the following:

That is, readsPrec parses the string produced by showsPrec, and delivers the value that showsPrec started with.

readList :: ReadS [a] #

The method readList is provided to allow the programmer to give a specialised way of parsing lists of values. For example, this is used by the predefined Read instance of the Char type, where values of type String should be are expected to use double quotes, rather than square brackets.

readPrec :: ReadPrec a #

Proposed replacement for readsPrec using new-style parsers (GHC only).

readListPrec :: ReadPrec [a] #

Proposed replacement for readList using new-style parsers (GHC only). The default definition uses readList. Instances that define readPrec should also define readListPrec as readListPrecDefault.

Instances

Instances details
Read Associativity

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

Read DecidedStrictness

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Read Fixity

Since: base-4.6.0.0

Instance details

Defined in GHC.Generics

Read SourceStrictness

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Read SourceUnpackedness

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Read ExitCode 
Instance details

Defined in GHC.IO.Exception

Read SomeChar 
Instance details

Defined in GHC.TypeLits

Read SomeSymbol

Since: base-4.7.0.0

Instance details

Defined in GHC.TypeLits

Read SomeNat

Since: base-4.7.0.0

Instance details

Defined in GHC.TypeNats

Read GeneralCategory

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word16

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word32

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word64

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word8

Since: base-2.1

Instance details

Defined in GHC.Read

Read Lexeme

Since: base-2.1

Instance details

Defined in GHC.Read

Read Ordering

Since: base-2.1

Instance details

Defined in GHC.Read

Read Integer

Since: base-2.1

Instance details

Defined in GHC.Read

Read Natural

Since: base-4.8.0.0

Instance details

Defined in GHC.Read

Read ()

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS () #

readList :: ReadS [()] #

readPrec :: ReadPrec () #

readListPrec :: ReadPrec [()] #

Read Bool

Since: base-2.1

Instance details

Defined in GHC.Read

Read Char

Since: base-2.1

Instance details

Defined in GHC.Read

Read Double

Since: base-2.1

Instance details

Defined in GHC.Read

Read Float

Since: base-2.1

Instance details

Defined in GHC.Read

Read Int

Since: base-2.1

Instance details

Defined in GHC.Read

Read Word

Since: base-4.5.0.0

Instance details

Defined in GHC.Read

Read p => Read (Par1 p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

(Integral a, Read a) => Read (Ratio a)

Since: base-2.1

Instance details

Defined in GHC.Read

Read a => Read (NonEmpty a)

Since: base-4.11.0.0

Instance details

Defined in GHC.Read

Read a => Read (Maybe a)

Since: base-2.1

Instance details

Defined in GHC.Read

Read a => Read (a)

Since: base-4.15

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a) #

readList :: ReadS [(a)] #

readPrec :: ReadPrec (a) #

readListPrec :: ReadPrec [(a)] #

Read a => Read [a]

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS [a] #

readList :: ReadS [[a]] #

readPrec :: ReadPrec [a] #

readListPrec :: ReadPrec [[a]] #

Read (f a) => Read (Reflected1 f a) Source # 
Instance details

Defined in AutoLift.Coercible

Read (f a) => Read (Reflected1 f a) Source # 
Instance details

Defined in AutoLift.Functor

Reifies s (ReadDict a) => Read (AdHoc s a) Source # 
Instance details

Defined in AutoLift.Machinery

(Read a, Read b) => Read (Either a b)

Since: base-3.0

Instance details

Defined in Data.Either

Read (Proxy t)

Since: base-4.7.0.0

Instance details

Defined in Data.Proxy

(Ix a, Read a, Read b) => Read (Array a b)

Since: base-2.1

Instance details

Defined in GHC.Read

Read (U1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Read (V1 p)

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

(Read a, Read b) => Read (a, b)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b) #

readList :: ReadS [(a, b)] #

readPrec :: ReadPrec (a, b) #

readListPrec :: ReadPrec [(a, b)] #

Read (f a b) => Read (Reflected2 f a b) Source # 
Instance details

Defined in AutoLift.Coercible

Read (f a b) => Read (Reflected2 f a b) Source # 
Instance details

Defined in AutoLift.Functor

Read a => Read (Const a b)

This instance would be equivalent to the derived instances of the Const newtype if the getConst field were removed

Since: base-4.8.0.0

Instance details

Defined in Data.Functor.Const

Read (f p) => Read (Rec1 f p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS (Rec1 f p) #

readList :: ReadS [Rec1 f p] #

readPrec :: ReadPrec (Rec1 f p) #

readListPrec :: ReadPrec [Rec1 f p] #

(Read a, Read b, Read c) => Read (a, b, c)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c) #

readList :: ReadS [(a, b, c)] #

readPrec :: ReadPrec (a, b, c) #

readListPrec :: ReadPrec [(a, b, c)] #

(Read (f p), Read (g p)) => Read ((f :*: g) p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS ((f :*: g) p) #

readList :: ReadS [(f :*: g) p] #

readPrec :: ReadPrec ((f :*: g) p) #

readListPrec :: ReadPrec [(f :*: g) p] #

(Read (f p), Read (g p)) => Read ((f :+: g) p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS ((f :+: g) p) #

readList :: ReadS [(f :+: g) p] #

readPrec :: ReadPrec ((f :+: g) p) #

readListPrec :: ReadPrec [(f :+: g) p] #

Read c => Read (K1 i c p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS (K1 i c p) #

readList :: ReadS [K1 i c p] #

readPrec :: ReadPrec (K1 i c p) #

readListPrec :: ReadPrec [K1 i c p] #

(Read a, Read b, Read c, Read d) => Read (a, b, c, d)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d) #

readList :: ReadS [(a, b, c, d)] #

readPrec :: ReadPrec (a, b, c, d) #

readListPrec :: ReadPrec [(a, b, c, d)] #

Read (f (g p)) => Read ((f :.: g) p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS ((f :.: g) p) #

readList :: ReadS [(f :.: g) p] #

readPrec :: ReadPrec ((f :.: g) p) #

readListPrec :: ReadPrec [(f :.: g) p] #

Read (f p) => Read (M1 i c f p)

Since: base-4.7.0.0

Instance details

Defined in GHC.Generics

Methods

readsPrec :: Int -> ReadS (M1 i c f p) #

readList :: ReadS [M1 i c f p] #

readPrec :: ReadPrec (M1 i c f p) #

readListPrec :: ReadPrec [M1 i c f p] #

(Read a, Read b, Read c, Read d, Read e) => Read (a, b, c, d, e)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e) #

readList :: ReadS [(a, b, c, d, e)] #

readPrec :: ReadPrec (a, b, c, d, e) #

readListPrec :: ReadPrec [(a, b, c, d, e)] #

(Read a, Read b, Read c, Read d, Read e, Read f) => Read (a, b, c, d, e, f)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f) #

readList :: ReadS [(a, b, c, d, e, f)] #

readPrec :: ReadPrec (a, b, c, d, e, f) #

readListPrec :: ReadPrec [(a, b, c, d, e, f)] #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g) => Read (a, b, c, d, e, f, g)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g) #

readList :: ReadS [(a, b, c, d, e, f, g)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g)] #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h) => Read (a, b, c, d, e, f, g, h)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h) #

readList :: ReadS [(a, b, c, d, e, f, g, h)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h)] #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i) => Read (a, b, c, d, e, f, g, h, i)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i)] #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j) => Read (a, b, c, d, e, f, g, h, i, j)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j)] #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k) => Read (a, b, c, d, e, f, g, h, i, j, k)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k)] #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k, Read l) => Read (a, b, c, d, e, f, g, h, i, j, k, l)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k, l) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k, l)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k, l) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k, l)] #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k, Read l, Read m) => Read (a, b, c, d, e, f, g, h, i, j, k, l, m)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k, l, m) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k, l, m)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k, l, m) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k, l, m)] #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k, Read l, Read m, Read n) => Read (a, b, c, d, e, f, g, h, i, j, k, l, m, n)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k, l, m, n) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k, l, m, n) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] #

(Read a, Read b, Read c, Read d, Read e, Read f, Read g, Read h, Read i, Read j, Read k, Read l, Read m, Read n, Read o) => Read (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)

Since: base-2.1

Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) #

readList :: ReadS [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] #

readPrec :: ReadPrec (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) #

readListPrec :: ReadPrec [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] #

class Read1 (f :: Type -> Type) where #

Lifting of the Read class to unary type constructors.

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) #

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] #

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) #

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] #

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
>>> 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) #

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

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Complex a) #

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Complex a] #

Read1 Identity

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Identity a) #

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Identity a] #

Read1 Down

Since: base-4.12.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Down a) #

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Down a] #

Read1 NonEmpty

Since: base-4.10.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (NonEmpty a) #

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [NonEmpty a] #

Read1 Maybe

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Maybe a) #

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Maybe a] #

Read1 Solo

Since: base-4.15

Instance details

Defined in Data.Functor.Classes

Methods

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

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

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Solo a) #

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Solo a] #

Read1 []

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [a] #

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

(forall a. Read a => Read (f a), forall xx yy. Coercible xx yy => Coercible (f xx) (f yy)) => Read1 (Reflected1 f) Source # 
Instance details

Defined in AutoLift.Coercible

Methods

liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Reflected1 f a) #

liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Reflected1 f a] #

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Reflected1 f a) #

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Reflected1 f a] #

(forall a. Read a => Read (f a), Functor f) => Read1 (Reflected1 f) Source # 
Instance details

Defined in AutoLift.Functor

Methods

liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Reflected1 f a) #

liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Reflected1 f a] #

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Reflected1 f a) #

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Reflected1 f a] #

Read a => Read1 (Either a)

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) #

liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [Either a a0] #

liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (Either a a0) #

liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [Either a a0] #

Read1 (Proxy :: Type -> Type)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

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

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

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Proxy a) #

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Proxy a] #

Read a => Read1 ((,) a)

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftReadsPrec :: (Int -> ReadS a0) -> ReadS [a0] -> Int -> ReadS (a, a0) #

liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [(a, a0)] #

liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (a, a0) #

liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [(a, a0)] #

(forall y. Read y => Read (f a y), forall x y. Coercible x y => Coercible (f a x) (f a y)) => Read1 (Reflected2 f a) Source # 
Instance details

Defined in AutoLift.Coercible

Methods

liftReadsPrec :: (Int -> ReadS a0) -> ReadS [a0] -> Int -> ReadS (Reflected2 f a a0) #

liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [Reflected2 f a a0] #

liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (Reflected2 f a a0) #

liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [Reflected2 f a a0] #

(forall y. Read y => Read (f a y), Functor (f a)) => Read1 (Reflected2 f a) Source # 
Instance details

Defined in AutoLift.Functor

Methods

liftReadsPrec :: (Int -> ReadS a0) -> ReadS [a0] -> Int -> ReadS (Reflected2 f a a0) #

liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [Reflected2 f a a0] #

liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (Reflected2 f a a0) #

liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [Reflected2 f a a0] #

Read a => Read1 (Const a :: Type -> Type)

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) #

liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [Const a a0] #

liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (Const a a0) #

liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [Const a a0] #

(Read a, Read b) => Read1 ((,,) a b)

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) #

liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [(a, b, a0)] #

liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (a, b, a0) #

liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [(a, b, a0)] #

(Read a, Read b, Read c) => Read1 ((,,,) a b c)

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) #

liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [(a, b, c, a0)] #

liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (a, b, c, a0) #

liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [(a, b, c, a0)] #

data ReadPrec a #

Instances

Instances details
MonadFail ReadPrec

Since: base-4.9.0.0

Instance details

Defined in Text.ParserCombinators.ReadPrec

Methods

fail :: String -> ReadPrec a #

Alternative ReadPrec

Since: base-4.6.0.0

Instance details

Defined in Text.ParserCombinators.ReadPrec

Methods

empty :: ReadPrec a #

(<|>) :: ReadPrec a -> ReadPrec a -> ReadPrec a #

some :: ReadPrec a -> ReadPrec [a] #

many :: ReadPrec a -> ReadPrec [a] #

Applicative ReadPrec

Since: base-4.6.0.0

Instance details

Defined in Text.ParserCombinators.ReadPrec

Methods

pure :: a -> ReadPrec a #

(<*>) :: ReadPrec (a -> b) -> ReadPrec a -> ReadPrec b #

liftA2 :: (a -> b -> c) -> ReadPrec a -> ReadPrec b -> ReadPrec c #

(*>) :: ReadPrec a -> ReadPrec b -> ReadPrec b #

(<*) :: ReadPrec a -> ReadPrec b -> ReadPrec a #

Functor ReadPrec

Since: base-2.1

Instance details

Defined in Text.ParserCombinators.ReadPrec

Methods

fmap :: (a -> b) -> ReadPrec a -> ReadPrec b #

(<$) :: a -> ReadPrec b -> ReadPrec a #

Monad ReadPrec

Since: base-2.1

Instance details

Defined in Text.ParserCombinators.ReadPrec

Methods

(>>=) :: ReadPrec a -> (a -> ReadPrec b) -> ReadPrec b #

(>>) :: ReadPrec a -> ReadPrec b -> ReadPrec b #

return :: a -> ReadPrec a #

MonadPlus ReadPrec

Since: base-2.1

Instance details

Defined in Text.ParserCombinators.ReadPrec

Methods

mzero :: ReadPrec a #

mplus :: ReadPrec a -> ReadPrec a -> ReadPrec a #