Safe Haskell	None
Language	Haskell2010

Optics.Internal.Optic.TypeLevel

Description

This module is intended for internal use only, and may change without warning in subsequent releases.

Synopsis

type IxList = [ Type ]
type NoIx = '[] :: IxList
type WithIx i = '[i] :: IxList
type family ShowSymbolWithOrigin symbol origin :: ErrorMessage where ...
type family ShowSymbolsWithOrigin (fs :: [( Symbol , Symbol )]) :: ErrorMessage where ...
type family ShowOperators (ops :: [ Symbol ]) :: ErrorMessage where ...
type family AppendEliminations a b where ...
type family ShowEliminations forms :: ErrorMessage where ...
type family Reverse (xs :: [k]) (acc :: [k]) :: [k] where ...
type family Curry (xs :: IxList ) (y :: Type ) :: Type where ...
type family Append (xs :: [k]) (ys :: [k]) :: [k] where ...
class CurryCompose xs where
- composeN :: (i -> j) -> Curry xs i -> Curry xs j
data IxEq i is js where
- IxEq :: IxEq i is is
class AppendIndices xs ys ks | xs ys -> ks where
- appendIndices :: IxEq i ( Curry xs ( Curry ys i)) ( Curry ks i)
type family FirstRight (m1 :: Either e a) (m2 :: Either e a) :: Either e a where ...
type family FromRight (def :: b) (e :: Either a b) :: b where ...
type family IsLeft (e :: Either a b) :: Bool where ...
type family When (p :: Bool ) (err :: Constraint ) :: Constraint where ...
type family Unless (p :: Bool ) (err :: Constraint ) :: Constraint where ...
type family Defined (f :: k) :: Bool where ...
type family QuoteType (x :: t) :: ErrorMessage where ...
type family QuoteSymbol (x :: Symbol ) :: ErrorMessage where ...
type family ToOrdinal (n :: Nat ) :: ErrorMessage where ...
class HasShapeOf (a :: k) (b :: k)

Documentation

type IxList = [ Type ] Source #

A list of index types, used for indexed optics.

Since: 0.2

type NoIx = '[] :: IxList Source #

An alias for an empty index-list

type WithIx i = '[i] :: IxList Source #

Singleton index list

type family ShowSymbolWithOrigin symbol origin :: ErrorMessage where ... Source #

Equations

ShowSymbolWithOrigin symbol origin = (((' Text " " :<>: QuoteSymbol symbol) :<>: ' Text " (from ") :<>: ' Text origin) :<>: ' Text ")"

type family ShowSymbolsWithOrigin (fs :: [( Symbol , Symbol )]) :: ErrorMessage where ... Source #

Equations

ShowSymbolsWithOrigin '['(symbol, origin)] = ShowSymbolWithOrigin symbol origin
ShowSymbolsWithOrigin ('(symbol, origin) ': rest) = ShowSymbolWithOrigin symbol origin :$$: ShowSymbolsWithOrigin rest

type family ShowOperators (ops :: [ Symbol ]) :: ErrorMessage where ... Source #

Equations

ShowOperators '[op] = QuoteSymbol op :<>: ' Text " (from Optics.Operators)"
ShowOperators (op ': rest) = ( QuoteSymbol op :<>: ' Text " ") :<>: ShowOperators rest

type family AppendEliminations a b where ... Source #

Equations

AppendEliminations '(fs1, ops1) '(fs2, ops2) = '( Append fs1 fs2, Append ops1 ops2)

type family ShowEliminations forms :: ErrorMessage where ... Source #

Equations

ShowEliminations '(fs, ops) = ShowSymbolsWithOrigin fs :$$: (' Text " " :<>: ShowOperators ops)

type family Reverse (xs :: [k]) (acc :: [k]) :: [k] where ... Source #

Reverse a type-level list.

Equations

Reverse '[] acc = acc
Reverse (x ': xs) acc = Reverse xs (x ': acc)

type family Curry (xs :: IxList ) (y :: Type ) :: Type where ... Source #

Curry a type-level list.

In pseudo (dependent-)Haskell:

Curry xs y = foldr (->) y xs

Equations

Curry '[] y = y
Curry (x ': xs) y = x -> Curry xs y

type family Append (xs :: [k]) (ys :: [k]) :: [k] where ... Source #

Append two type-level lists together.

Equations

Append '[] ys = ys
Append xs '[] = xs
Append (x ': xs) ys = x ': Append xs ys

class CurryCompose xs where Source #

Class that is inhabited by all type-level lists xs , providing the ability to compose a function under Curry xs .

Methods

composeN :: (i -> j) -> Curry xs i -> Curry xs j Source #

Compose a function under Curry xs . This generalises ( . ) (aka fmap for (->) ) to work for curried functions with one argument for each type in the list.

Instances

Instances details

CurryCompose ('[] :: [ Type ]) Source #
Instance details Defined in Optics.Internal.Optic.TypeLevel Methods composeN :: (i -> j) -> Curry '[] i -> Curry '[] j Source #
CurryCompose xs => CurryCompose (x ': xs) Source #
Instance details Defined in Optics.Internal.Optic.TypeLevel Methods composeN :: (i -> j) -> Curry (x ': xs) i -> Curry (x ': xs) j Source #

data IxEq i is js where Source #

Tagged version of 'Data.Type.Equality.(:~:)' for carrying evidence that two index lists in a curried form are equal.

Constructors

IxEq :: IxEq i is is

class AppendIndices xs ys ks | xs ys -> ks where Source #

In pseudo (dependent-)Haskell, provide a witness

foldr f (foldr f init xs) ys = foldr f init (ys ++ xs)
   where f = (->)

Since: 0.4

Methods

appendIndices :: IxEq i ( Curry xs ( Curry ys i)) ( Curry ks i) Source #

Instances

Instances details

AppendIndices xs ('[] :: [ Type ]) xs Source #	If the second list is empty, we can shortcircuit and pick the first list immediately.
Instance details Defined in Optics.Internal.Optic.TypeLevel Methods appendIndices :: IxEq i ( Curry xs ( Curry '[] i)) ( Curry xs i) Source #
AppendIndices ('[] :: [ Type ]) ys ys Source #
Instance details Defined in Optics.Internal.Optic.TypeLevel Methods appendIndices :: IxEq i ( Curry '[] ( Curry ys i)) ( Curry ys i) Source #
AppendIndices xs ys ks => AppendIndices (x ': xs) ys (x ': ks) Source #
Instance details Defined in Optics.Internal.Optic.TypeLevel Methods appendIndices :: IxEq i ( Curry (x ': xs) ( Curry ys i)) ( Curry (x ': ks) i) Source #

type family FirstRight (m1 :: Either e a) (m2 :: Either e a) :: Either e a where ... Source #

If lhs is Right , return it. Otherwise check rhs.

Equations

FirstRight (' Right a) _ = ' Right a
FirstRight _ b = b

type family FromRight (def :: b) (e :: Either a b) :: b where ... Source #

Equations

FromRight _ (' Right b) = b
FromRight def (' Left _) = def

type family IsLeft (e :: Either a b) :: Bool where ... Source #

Equations

IsLeft (' Left _) = ' True
IsLeft (' Right _) = ' False

type family When (p :: Bool ) (err :: Constraint ) :: Constraint where ... Source #

Show a custom type error if p is true.

Equations

When ' True err = err
When ' False _ = ()

type family Unless (p :: Bool ) (err :: Constraint ) :: Constraint where ... Source #

Show a custom type error if p is false (or stuck).

Equations

Unless ' True _ = ()
Unless ' False err = err

type family Defined (f :: k) :: Bool where ... Source #

Use with Unless to detect stuck (undefined) type families.

Equations

Defined (f _) = Defined f
Defined _ = ' True

type family QuoteType (x :: t) :: ErrorMessage where ... Source #

Show a type surrounded by quote marks.

Equations

QuoteType x = (' Text "\8216" :<>: ' ShowType x) :<>: ' Text "\8217"

type family QuoteSymbol (x :: Symbol ) :: ErrorMessage where ... Source #

Show a symbol surrounded by quote marks.

Equations

QuoteSymbol x = (' Text "\8216" :<>: ' Text x) :<>: ' Text "\8217"

type family ToOrdinal (n :: Nat ) :: ErrorMessage where ... Source #

Equations

ToOrdinal 1 = ' Text "1st"
ToOrdinal 2 = ' Text "2nd"
ToOrdinal 3 = ' Text "3rd"
ToOrdinal n = ' ShowType n :<>: ' Text "th"

class HasShapeOf (a :: k) (b :: k) Source #

Derive the shape of a from the shape of b .

Instances

Instances details

a ~ b => HasShapeOf (a :: k) (b :: k) Source #
Instance details Defined in Optics.Internal.Optic.TypeLevel
(fa ~ f a, HasShapeOf f g) => HasShapeOf (fa :: k1) (g b :: k1) Source #
Instance details Defined in Optics.Internal.Optic.TypeLevel