| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Optics.Internal.Optic
Contents
Description
Core optic types and subtyping machinery.
This module contains the core
Optic
types, and the underlying
machinery that we need in order to implement the subtyping between
various different flavours of optics.
The composition operator for optics is also defined here.
This module is intended for internal use only, and may change without warning in subsequent releases.
Synopsis
- newtype Optic (k :: OpticKind ) (is :: IxList ) s t a b = Optic ( forall p i. Profunctor p => Optic_ k p i ( Curry is i) s t a b)
- type Optic' k is s a = Optic k is s s a a
- type Optic_ k p i j s t a b = Constraints k p => Optic__ p i j s t a b
- type Optic__ p i j s t a b = p i a b -> p j s t
- getOptic :: Profunctor p => Optic k is s t a b -> Optic_ k p i ( Curry is i) s t a b
- castOptic :: forall destKind srcKind is s t a b. Is srcKind destKind => Optic srcKind is s t a b -> Optic destKind is s t a b
- (%) :: forall k l m is js ks s t u v a b. ( JoinKinds k l m, AppendIndices is js ks) => Optic k is s t u v -> Optic l js u v a b -> Optic m ks s t a b
- (%%) :: forall k is js ks s t u v a b. AppendIndices is js ks => Optic k is s t u v -> Optic k js u v a b -> Optic k ks s t a b
- (%&) :: Optic k is s t a b -> ( Optic k is s t a b -> Optic l js s' t' a' b') -> Optic l js s' t' a' b'
- module Optics.Internal.Optic.Subtyping
- module Optics.Internal.Optic.Types
- module Optics.Internal.Optic.TypeLevel
Documentation
newtype Optic (k :: OpticKind ) (is :: IxList ) s t a b Source #
Wrapper newtype for the whole family of optics.
The first parameter
k
identifies the particular optic kind (e.g.
A_Lens
or
A_Traversal
).
The parameter
is
is a list of types available as indices. This will
typically be
NoIx
for unindexed optics, or
WithIx
for optics with a
single index. See the "Indexed optics" section of the overview documentation
in the
Optics
module of the main
optics
package for more details.
The parameters
s
and
t
represent the "big" structure,
whereas
a
and
b
represent the "small" structure.
Constructors
| Optic ( forall p i. Profunctor p => Optic_ k p i ( Curry is i) s t a b) |
type Optic' k is s a = Optic k is s s a a Source #
Common special case of
Optic
where source and target types are equal.
Here, we need only one "big" and one "small" type. For lenses, this means that in the restricted form we cannot do type-changing updates.
type Optic_ k p i j s t a b = Constraints k p => Optic__ p i j s t a b Source #
Type representing the various kinds of optics.
The tag parameter
k
is translated into constraints on
p
via the type family
Constraints
.
type Optic__ p i j s t a b = p i a b -> p j s t Source #
Optic internally as a profunctor transformation.
getOptic :: Profunctor p => Optic k is s t a b -> Optic_ k p i ( Curry is i) s t a b Source #
Strip the newtype wrapper off.
castOptic :: forall destKind srcKind is s t a b. Is srcKind destKind => Optic srcKind is s t a b -> Optic destKind is s t a b Source #
(%) :: forall k l m is js ks s t u v a b. ( JoinKinds k l m, AppendIndices is js ks) => Optic k is s t u v -> Optic l js u v a b -> Optic m ks s t a b infixl 9 Source #
Compose two optics of compatible flavours.
Returns an optic of the appropriate supertype. If either or both optics are indexed, the composition preserves all the indices.
(%%) :: forall k is js ks s t u v a b. AppendIndices is js ks => Optic k is s t u v -> Optic k js u v a b -> Optic k ks s t a b infixl 9 Source #
Compose two optics of the same flavour.
Normally you can simply use (
%
) instead, but this may be useful to help
type inference if the type of one of the optics is otherwise
under-constrained.
(%&) :: Optic k is s t a b -> ( Optic k is s t a b -> Optic l js s' t' a' b') -> Optic l js s' t' a' b' infixl 9 Source #
Flipped function application, specialised to optics and binding tightly.
Useful for post-composing optics transformations:
>>>toListOf (ifolded %& ifiltered (\i s -> length s <= i)) ["", "a","abc"]["","a"]
Re-exports
module Optics.Internal.Optic.Types