Moduleoptics-core-0.4.2Haskell2010

Optics.Internal.Optic.TypeLevel

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

4 types
3 classes

Packageoptics-core-0.4.2
Exports24
LanguageHaskell2010
LicenceBSD-3-Clause
SourceTypeLevel.hs

typetype IxList = [Type]

A list of index types, used for indexed optics.

typetype NoIx = '[]

An alias for an empty index-list

typetype WithIx i = '[i]

Singleton index list

familytype family ShowSymbolWithOrigin (symbol :: Symbol) (origin :: Symbol) :: ErrorMessage where

Equations

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

familytype family ShowSymbolsWithOrigin (fs :: [(Symbol, Symbol)]) :: ErrorMessage where

Equations

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

familytype family ShowOperators (ops :: [Symbol]) :: ErrorMessage where

Equations

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

familytype family AppendEliminations (a :: ([k], [k1])) (b :: ([k], [k1])) :: ([k], [k1]) where

Equations

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

familytype family ShowEliminations (forms :: ([(Symbol, Symbol)], [Symbol])) :: ErrorMessage where

Equations

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

familytype family Reverse (xs :: [k]) (acc :: [k]) :: [k] where

Reverse a type-level list.

Equations

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

familytype family Curry (xs :: IxList) y where

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

familytype family Append (xs :: [k]) (ys :: [k]) :: [k] where

Append two type-level lists together.

Equations

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

classclass CurryCompose (xs :: IxList) where

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
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.

Instances2CurryCompose

CurryCompose '[]Defined in optics-core-0.4.2 · Optics.Internal.Optic.TypeLevel
CurryCompose xs => CurryCompose (x ': xs)Defined in optics-core-0.4.2 · Optics.Internal.Optic.TypeLevel

datadata IxEq (i :: k) (is :: k1) (js :: k1) where

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

classclass AppendIndices (xs :: IxList) (ys :: IxList) (ks :: IxList) | xs ys -> ks where

In pseudo (dependent-)Haskell, provide a witness

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

Methods

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

Instances3AppendIndices

xs ~ zs => AppendIndices xs '[] zsDefined in optics-core-0.4.2 · Optics.Internal.Optic.TypeLevel
If the second list is empty, we can pick the first list even if nothing is known about it.
ys ~ zs => AppendIndices '[] ys zsDefined in optics-core-0.4.2 · Optics.Internal.Optic.TypeLevel
AppendIndices xs ys ks => AppendIndices (x ': xs) ys (x ': ks)Defined in optics-core-0.4.2 · Optics.Internal.Optic.TypeLevel

familytype family FirstRight (m1 :: Either e a) (m2 :: Either e a) :: Either e a where

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

Equations

FirstRight ('Right a) _1 = 'Right a
FirstRight _1 b = b

familytype family FromRight (def :: b) (e :: Either a b) :: b where

Equations

FromRight _1 ('Right b2) = b2
FromRight def ('Left _1) = def

familytype family IsLeft (e :: Either a b) :: Bool where

Equations

IsLeft ('Left _1) = 'True
IsLeft ('Right _1) = 'False

familytype family When (p :: Bool) (err :: Constraint) :: Constraint where

Show a custom type error if p is true.

Equations

When 'True err = err
When 'False _1 = ()

familytype family Unless (p :: Bool) (err :: Constraint) :: Constraint where

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

Equations

Unless 'True _1 = ()
Unless 'False err = err

familytype family Defined (f :: k) :: Bool where

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

Equations

Defined (f _1) = Defined f
Defined _1 = 'True

familytype family QuoteType (x :: t) :: ErrorMessage where

Show a type surrounded by quote marks.

Equations

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

familytype family QuoteSymbol (x :: Symbol) :: ErrorMessage where

Show a symbol surrounded by quote marks.

Equations

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

familytype family ToOrdinal (n :: Nat) :: ErrorMessage where

Equations

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

classclass HasShapeOf (a :: k) (b :: k)

Derive the shape of a from the shape of b.

Instances2HasShapeOf

a ~ b => HasShapeOf a bDefined in optics-core-0.4.2 · Optics.Internal.Optic.TypeLevel
(fa ~ f a, HasShapeOf f g) => HasShapeOf fa (g b)Defined in optics-core-0.4.2 · Optics.Internal.Optic.TypeLevel