Safe Haskell	Safe-Inferred
Language	Haskell2010

Fresnel.Iso

Contents

Isos
Construction
Elimination
Functions
Relations
Tuples
Coercion
Functor
Contravariant
Bifunctor
Profunctor
(Co-)representable

Description

Isos are the root of the optic hierarchy: an Iso can be used anywhere any other kind of optic is required. On the other hand, if something requests an Iso, it can only be given an Iso, as it doesn't provide enough capabilities to accept anything else.

This implies that they're the weakest optic; they make the fewest assumptions, and thus can provide only the most minimal guarantees. Even so, these guarantees are relativevly strong: notionally, an Iso consists of functions f and g which are mutual inverses:

f . g = id

g . f = id

Synopsis

type Iso s t a b = forall p. IsIso p => Optic p s t a b
type Iso' s a = Iso s s a a
class Profunctor p => IsIso p
iso :: (s -> a) -> (b -> t) -> Iso s t a b
from :: Iso s t a b -> Iso b a t s
withIso :: Iso s t a b -> ((s -> a) -> (b -> t) -> r) -> r
under :: Iso s t a b -> (t -> s) -> b -> a
constant :: a -> Iso (a -> b) (a' -> b') b b'
constantWith :: a -> (b' -> a' -> b') -> Iso (a -> b) (a' -> b') b b'
involuted :: (a -> a) -> Iso' a a
flipped :: Iso (a -> b -> c) (a' -> b' -> c') (b -> a -> c) (b' -> a' -> c')
curried :: Iso ((a, b) -> c) ((a', b') -> c') (a -> b -> c) (a' -> b' -> c')
uncurried :: Iso (a -> b -> c) (a' -> b' -> c') ((a, b) -> c) ((a', b') -> c')
non :: Eq a => a -> Iso' (Maybe a) a
non' :: Prism' a () -> Iso' (Maybe a) a
swapped :: Iso (a, b) (a', b') (b, a) (b', a')
mirrored :: Iso (Either a b) (Either a' b') (Either b a) (Either b' a')
coerced :: (Coercible s a, Coercible t b) => Iso s t a b
coercedTo :: Coercible t b => (s -> a) -> Iso s t a b
coercedFrom :: Coercible s a => (b -> t) -> Iso s t a b
fmapping :: (Functor f, Functor g) => Iso s t a b -> Iso (f s) (g t) (f a) (g b)
contramapping :: (Contravariant f, Contravariant g) => Iso s t a b -> Iso (f a) (g b) (f s) (g t)
bimapping :: (Bifunctor p, Bifunctor q) => Iso s t a b -> Iso s' t' a' b' -> Iso (p s s') (q t t') (p a a') (q b b')
firsting :: (Bifunctor p, Bifunctor q) => Iso s t a b -> Iso (p s x) (q t y) (p a x) (q b y)
seconding :: (Bifunctor p, Bifunctor q) => Iso s t a b -> Iso (p x s) (q y t) (p x a) (q y b)
dimapping :: (Profunctor p, Profunctor q) => Iso s t a b -> Iso s' t' a' b' -> Iso (p a s') (q b t') (p s a') (q t b')
lmapping :: (Profunctor p, Profunctor q) => Iso s t a b -> Iso (p a x) (q b y) (p s x) (q t y)
rmapping :: (Profunctor p, Profunctor q) => Iso s t a b -> Iso (p x s) (q y t) (p x a) (q y b)
protabulated :: (Representable p, Representable q) => Iso (a -> Rep p b) (a' -> Rep q b') (p a b) (q a' b')
cotabulated :: (Corepresentable p, Corepresentable q) => Iso (Corep p a -> b) (Corep q a' -> b') (p a b) (q a' b')

Isos

type Iso s t a b = forall p. IsIso p => Optic p s t a b Source #

type Iso' s a = Iso s s a a Source #

class Profunctor p => IsIso p Source #

Instances

Instances details

Monad m => IsIso (Kleisli m) Source #
Instance details Defined in Fresnel.Iso.Internal
Functor f => IsIso (OptionalStar f) Source #
Instance details Defined in Fresnel.Iso.Internal
IsIso (Recall e) Source #
Instance details Defined in Fresnel.Iso.Internal
IsIso (UnpackedLens a b) Source #
Instance details Defined in Fresnel.Lens
IsIso (UnpackedOptional a b) Source #
Instance details Defined in Fresnel.Optional
IsIso (UnpackedPrism a b) Source #
Instance details Defined in Fresnel.Prism
IsIso (Coexp s t) Source #
Instance details Defined in Fresnel.Iso.Internal
Functor f => IsIso (Costar f) Source #
Instance details Defined in Fresnel.Iso.Internal
IsIso (Forget r :: Type -> Type -> Type) Source #
Instance details Defined in Fresnel.Iso.Internal
Functor f => IsIso (Star f) Source #
Instance details Defined in Fresnel.Iso.Internal
IsIso (->) Source #
Instance details Defined in Fresnel.Iso.Internal

Construction

iso :: (s -> a) -> (b -> t) -> Iso s t a b Source #

from :: Iso s t a b -> Iso b a t s Source #

Elimination

withIso :: Iso s t a b -> ((s -> a) -> (b -> t) -> r) -> r Source #

under :: Iso s t a b -> (t -> s) -> b -> a Source #

Functions

constant :: a -> Iso (a -> b) (a' -> b') b b' Source #

constantWith :: a -> (b' -> a' -> b') -> Iso (a -> b) (a' -> b') b b' Source #

involuted :: (a -> a) -> Iso' a a Source #

flipped :: Iso (a -> b -> c) (a' -> b' -> c') (b -> a -> c) (b' -> a' -> c') Source #

curried :: Iso ((a, b) -> c) ((a', b') -> c') (a -> b -> c) (a' -> b' -> c') Source #

uncurried :: Iso (a -> b -> c) (a' -> b' -> c') ((a, b) -> c) ((a', b') -> c') Source #

Relations

non :: Eq a => a -> Iso' (Maybe a) a Source #

non' :: Prism' a () -> Iso' (Maybe a) a Source #

Tuples

swapped :: Iso (a, b) (a', b') (b, a) (b', a') Source #

mirrored :: Iso (Either a b) (Either a' b') (Either b a) (Either b' a') Source #

Coercion

coerced :: (Coercible s a, Coercible t b) => Iso s t a b Source #

coercedTo :: Coercible t b => (s -> a) -> Iso s t a b Source #

Build a bidi coercion, taking a constructor for the type being built both to improve type inference and as documentation.

For example, given two newtypes A and B wrapping the same type, this expression:

coercedTo B <<< coercedFrom A

produces a bijection of type Iso' A B.

coercedFrom :: Coercible s a => (b -> t) -> Iso s t a b Source #

Build a bidi coercion, taking a constructor for the type being eliminated both to improve type inference and as documentation.

For example, given two newtypes A and B wrapping the same type, this expression:

coercedTo B <<< coercedFrom A

produces a bijection of type Iso' A B.

Functor

fmapping :: (Functor f, Functor g) => Iso s t a b -> Iso (f s) (g t) (f a) (g b) Source #

Contravariant

contramapping :: (Contravariant f, Contravariant g) => Iso s t a b -> Iso (f a) (g b) (f s) (g t) Source #

Bifunctor

bimapping :: (Bifunctor p, Bifunctor q) => Iso s t a b -> Iso s' t' a' b' -> Iso (p s s') (q t t') (p a a') (q b b') Source #

firsting :: (Bifunctor p, Bifunctor q) => Iso s t a b -> Iso (p s x) (q t y) (p a x) (q b y) Source #

seconding :: (Bifunctor p, Bifunctor q) => Iso s t a b -> Iso (p x s) (q y t) (p x a) (q y b) Source #

Profunctor

dimapping :: (Profunctor p, Profunctor q) => Iso s t a b -> Iso s' t' a' b' -> Iso (p a s') (q b t') (p s a') (q t b') Source #

lmapping :: (Profunctor p, Profunctor q) => Iso s t a b -> Iso (p a x) (q b y) (p s x) (q t y) Source #

rmapping :: (Profunctor p, Profunctor q) => Iso s t a b -> Iso (p x s) (q y t) (p x a) (q y b) Source #

(Co-)representable

protabulated :: (Representable p, Representable q) => Iso (a -> Rep p b) (a' -> Rep q b') (p a b) (q a' b') Source #

cotabulated :: (Corepresentable p, Corepresentable q) => Iso (Corep p a -> b) (Corep q a' -> b') (p a b) (q a' b') Source #