Portability	non-portable
Stability	experimental
Maintainer	generics@haskell.org
Safe Haskell	Safe-Inferred

Generics.Instant.Base

Description

This module defines the basic representation types and the conversion functions to and from. A typical instance for a user-defined datatype would be:

 -- Example datatype
 data Exp = Const Int | Plus Exp Exp

 -- Auxiliary datatypes for constructor representations
 data Const
 data Plus
 
 instance Constructor Const where conName _ = "Const"
 instance Constructor Plus  where conName _ = "Plus"
 
 -- Representable instance
 instance Representable Exp where
   type Rep Exp = C Const (Var Int) :+: C Plus (Rec Exp :*: Rec Exp)
 
   from (Const n)   = L (C (Var n))
   from (Plus e e') = R (C (Rec e :*: Rec e'))
 
   to (L (C (Var n)))            = Const n
   to (R (C (Rec e :*: Rec e'))) = Plus e e'

Synopsis

Documentation

data Z Source

data U Source

Constructors

U

Instances

Read U
Show U
Representable U
HasRec U
Empty U
GShow' U
GEq' U

data a :+: b Source

Constructors

L a
R b

Instances

(Read a, Read b) => Read (:+: a b)
(Show a, Show b) => Show (:+: a b)
(Representable a, Representable b) => Representable (:+: a b)
(HasRec a, HasRec b) => HasRec (:+: a b)
(HasRec a, Empty a, Empty b) => Empty (:+: a b)
(GShow' a, GShow' b) => GShow' (:+: a b)
(GEq' a, GEq' b) => GEq' (:+: a b)

data a :*: b Source

Constructors

a :*: b

Instances

(Read a, Read b) => Read (:*: a b)
(Show a, Show b) => Show (:*: a b)
(Representable a, Representable b) => Representable (:*: a b)
(HasRec a, HasRec b) => HasRec (:*: a b)
(Empty a, Empty b) => Empty (:*: a b)
(GShow' a, GShow' b) => GShow' (:*: a b)
(GEq' a, GEq' b) => GEq' (:*: a b)

data CEq c p q a whereSource

Constructors

C :: a -> CEq c p p a

Instances

Read a => Read (CEq c p p a)
Show a => Show (CEq c p q a)
Representable a => Representable (CEq c p q a)
HasRec a => HasRec (CEq c p q a)
Empty a => Empty (CEq c p p a)
(GShow' a, Constructor c) => GShow' (CEq c p q a)
GEq' a => GEq' (CEq c p q a)

type C c a = CEq c () () aSource

data Var a Source

Constructors

Var a

Instances

Read a => Read (Var a)
Show a => Show (Var a)
Representable a => Representable (Var a)
HasRec (Var a)
Empty a => Empty (Var a)
GShow a => GShow' (Var a)
GEq a => GEq' (Var a)

data Rec a Source

Constructors

Rec a

Instances

Read a => Read (Rec a)
Show a => Show (Rec a)
Representable a => Representable (Rec a)
HasRec (Rec a)
Empty a => Empty (Rec a)
GShow a => GShow' (Rec a)
GEq a => GEq' (Rec a)

class Constructor c whereSource

Class for datatypes that represent data constructors. For non-symbolic constructors, only conName has to be defined.

Methods

conName :: t c p q a -> String Source

conFixity :: t c p q a -> Fixity Source

conIsRecord :: t c p q a -> Bool Source

Instances

Constructor Tuple_Pair_
Constructor Maybe_Just_
Constructor Maybe_Nothing_
Constructor List_Cons_
Constructor List_Nil_

data Fixity Source

Datatype to represent the fixity of a constructor. An infix declaration directly corresponds to an application of Infix.

Constructors

Prefix
Infix Associativity Int

Instances

Eq Fixity
Ord Fixity
Read Fixity
Show Fixity
Lift Fixity

data Associativity Source

Datatype to represent the associativy of a constructor.

Constructors

LeftAssociative
RightAssociative
NotAssociative

Instances

Eq Associativity
Ord Associativity
Read Associativity
Show Associativity
Lift Associativity

class Representable a whereSource

Associated Types

type Rep a Source

Methods

to :: Rep a -> aSource

from :: a -> Rep aSource

Instances

Representable Bool
Representable Char
Representable Float
Representable Int
Representable U
Representable [a]
Representable (Maybe a)
Representable a => Representable (Rec a)
Representable a => Representable (Var a)
Representable (a, b)
(Representable a, Representable b) => Representable (:*: a b)
(Representable a, Representable b) => Representable (:+: a b)
Representable a => Representable (CEq c p q a)

type family X c n a Source

data Ze Source

data Su Source