Control.Lens.Internal.Context

Documentation

class IndexedFunctor w where

This is a Bob Atkey -style 2-argument indexed functor.

It exists as a superclass for IndexedComonad and expresses the functoriality of an IndexedComonad in its third argument.

Methods

ifmap :: (s -> t) -> w a b s -> w a b t

Instances

IndexedFunctor Context

IndexedFunctor Mafic

IndexedFunctor (Pretext p)

IndexedFunctor (Bazaar p)

IndexedFunctor (Molten i)

IndexedFunctor (PretextT p g)

IndexedFunctor (BazaarT p g)

IndexedFunctor (TakingWhile p f)

class IndexedFunctor w => IndexedComonad w where

This is a Bob Atkey -style 2-argument indexed comonad.

It exists as a superclass for IndexedComonad and expresses the functoriality of an IndexedComonad in its third argument.

The notion of indexed monads is covered in more depth in Bob Atkey's Parameterized Notions of Computation http://bentnib.org/paramnotions-jfp.pdf and that construction is dualized here.

Methods

iextract :: w a a t -> t

extract from an indexed comonadic value when the indices match.

iduplicate :: w a c t -> w a b (w b c t)

duplicate an indexed comonadic value splitting the index.

iextend :: (w b c t -> r) -> w a c t -> w a b r

extend a indexed comonadic computation splitting the index.

Instances

IndexedComonad Context

Conjoined p => IndexedComonad (Pretext p)

Conjoined p => IndexedComonad (Bazaar p)

IndexedComonad (Molten i)

Conjoined p => IndexedComonad (PretextT p g)

Conjoined p => IndexedComonad (BazaarT p g)

class IndexedComonad w => IndexedComonadStore w where

This is an indexed analogue to ComonadStore for when you are working with an IndexedComonad.

Methods

ipos :: w a c t -> a

This is the generalization of pos to an indexed comonad store.

ipeek :: c -> w a c t -> t

This is the generalization of peek to an indexed comonad store.

ipeeks :: (a -> c) -> w a c t -> t

This is the generalization of peeks to an indexed comonad store.

iseek :: b -> w a c t -> w b c t

This is the generalization of seek to an indexed comonad store.

iseeks :: (a -> b) -> w a c t -> w b c t

This is the generalization of seeks to an indexed comonad store.

iexperiment :: Functor f => (b -> f c) -> w b c t -> f t

This is the generalization of experiment to an indexed comonad store.

context :: w a b t -> Context a b t

We can always forget the rest of the structure of w and obtain a simpler indexed comonad store model called Context.

Instances

IndexedComonadStore Context

Conjoined p => IndexedComonadStore (Pretext p)

Conjoined p => IndexedComonadStore (PretextT p g)

class Corepresentable p => Sellable p w | w -> p where

This is used internally to construct a Bazaar, Context or Pretext from a singleton value.

Methods

sell :: p a (w a b b)

Instances

Sellable (->) Context

Sellable (->) Mafic

Corepresentable p => Sellable p (Pretext p)

Corepresentable p => Sellable p (Bazaar p)

Corepresentable p => Sellable p (PretextT p g)

Corepresentable p => Sellable p (BazaarT p g)

Sellable (Indexed i) (Molten i)

data Context a b t

The indexed store can be used to characterize a Lens and is used by clone.

Context a b t is isomorphic to newtype Context a b t = Context { runContext :: forall f. Functor f => (a -> f b) -> f t }, and to exists s. (s, Lens s t a b).

A Context is like a Lens that has already been applied to a some structure.

Constructors

Context (b -> t) a

Instances

IndexedComonadStore Context

IndexedComonad Context

IndexedFunctor Context

Sellable (->) Context

~ * a b => ComonadStore a (Context a b)

Functor (Context a b)

~ * a b => Comonad (Context a b)

type Context' a = Context a a

type Context' a s = Context a a s

newtype Pretext p a b t

This is a generalized form of Context that can be repeatedly cloned with less impact on its performance, and which permits the use of an arbitrary Conjoined Profunctor

Constructors

Pretext

Fields

runPretext :: forall f. Functor f => p a (f b) -> f t

Instances

Corepresentable p => Sellable p (Pretext p)

(~ * a b, Conjoined p) => ComonadStore a (Pretext p a b)

Conjoined p => IndexedComonadStore (Pretext p)

Conjoined p => IndexedComonad (Pretext p)

IndexedFunctor (Pretext p)

Functor (Pretext p a b)

(~ * a b, Conjoined p) => Comonad (Pretext p a b)

type Pretext' p a = Pretext p a a

type Pretext' p a s = Pretext p a a s

newtype PretextT p g a b t

This is a generalized form of Context that can be repeatedly cloned with less impact on its performance, and which permits the use of an arbitrary Conjoined Profunctor.

The extra phantom Functor is used to let us lie and claim a Gettable instance under limited circumstances. This is used internally to permit a number of combinators to gracefully degrade when applied to a Fold, Getter or Action.

Constructors

PretextT

Fields

runPretextT :: forall f. Functor f => p a (f b) -> f t

Instances

Corepresentable p => Sellable p (PretextT p g)

(~ * a b, Conjoined p) => ComonadStore a (PretextT p g a b)

Conjoined p => IndexedComonadStore (PretextT p g)

Conjoined p => IndexedComonad (PretextT p g)

IndexedFunctor (PretextT p g)

Functor (PretextT p g a b)

(~ * a b, Conjoined p) => Comonad (PretextT p g a b)

(Profunctor p, Contravariant g) => Contravariant (PretextT p g a b)

type PretextT' p g a = PretextT p g a a

type PretextT' p g a s = PretextT p g a a s