Safe Haskell | Safe-Inferred |
---|---|
Language | Haskell2010 |
Synopsis
- type IxFold i s a = Optic' A_Fold (WithIx i) s a
- ifoldVL :: (forall f. Applicative f => (i -> a -> f u) -> s -> f v) -> IxFold i s a
- ifoldMapOf :: (Is k A_Fold, Monoid m, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> m) -> s -> m
- ifoldrOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> r -> r) -> r -> s -> r
- ifoldlOf' :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> (i -> r -> a -> r) -> r -> s -> r
- itoListOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> s -> [(i, a)]
- itraverseOf_ :: (Is k A_Fold, Applicative f, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> f r) -> s -> f ()
- iforOf_ :: (Is k A_Fold, Applicative f, is `HasSingleIndex` i) => Optic' k is s a -> s -> (i -> a -> f r) -> f ()
- ifolded :: FoldableWithIndex i f => IxFold i (f a) a
- ifolding :: FoldableWithIndex i f => (s -> f a) -> IxFold i s a
- ifoldring :: (forall f. Applicative f => (i -> a -> f u -> f u) -> f v -> s -> f w) -> IxFold i s a
- iheadOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> s -> Maybe (i, a)
- ilastOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> s -> Maybe (i, a)
- ianyOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> Bool) -> s -> Bool
- iallOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> Bool) -> s -> Bool
- inoneOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> Bool) -> s -> Bool
- ifindOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> Bool) -> s -> Maybe (i, a)
- ifindMOf :: (Is k A_Fold, Monad m, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> m Bool) -> s -> m (Maybe (i, a))
- ipre :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> IxAffineFold i s a
- ifiltered :: (Is k A_Fold, is `HasSingleIndex` i) => (i -> a -> Bool) -> Optic' k is s a -> IxFold i s a
- ibackwards_ :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> IxFold i s a
- isumming :: (Is k A_Fold, Is l A_Fold, is1 `HasSingleIndex` i, is2 `HasSingleIndex` i) => Optic' k is1 s a -> Optic' l is2 s a -> IxFold i s a
- ifailing :: (Is k A_Fold, Is l A_Fold, is1 `HasSingleIndex` i, is2 `HasSingleIndex` i) => Optic' k is1 s a -> Optic' l is2 s a -> IxFold i s a
- data A_Fold :: OpticKind
- class Foldable f => FoldableWithIndex i (f :: Type -> Type) | f -> i where
Formation
Introduction
ifoldVL :: (forall f. Applicative f => (i -> a -> f u) -> s -> f v) -> IxFold i s a Source #
Obtain an indexed fold by lifting itraverse_
like function.
ifoldVL
.
itraverseOf_
≡id
itraverseOf_
.
ifoldVL
≡id
Elimination
ifoldMapOf :: (Is k A_Fold, Monoid m, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> m) -> s -> m Source #
Fold with index via embedding into a monoid.
ifoldrOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> r -> r) -> r -> s -> r Source #
Fold with index right-associatively.
ifoldlOf' :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> (i -> r -> a -> r) -> r -> s -> r Source #
Fold with index left-associatively, and strictly.
itoListOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> s -> [(i, a)] Source #
Fold with index to a list.
>>>
itoListOf (folded % ifolded) ["abc", "def"]
[(0,'a'),(1,'b'),(2,'c'),(0,'d'),(1,'e'),(2,'f')]
Note: currently indexed optics can be used as non-indexed.
>>>
toListOf (folded % ifolded) ["abc", "def"]
"abcdef"
itraverseOf_ :: (Is k A_Fold, Applicative f, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> f r) -> s -> f () Source #
Traverse over all of the targets of an IxFold
, computing an
Applicative
-based answer, but unlike itraverseOf
do
not construct a new structure.
>>>
itraverseOf_ each (curry print) ("hello","world")
(0,"hello") (1,"world")
iforOf_ :: (Is k A_Fold, Applicative f, is `HasSingleIndex` i) => Optic' k is s a -> s -> (i -> a -> f r) -> f () Source #
A version of itraverseOf_
with the arguments flipped.
Additional introduction forms
ifolded :: FoldableWithIndex i f => IxFold i (f a) a Source #
Indexed fold via FoldableWithIndex
class.
ifolding :: FoldableWithIndex i f => (s -> f a) -> IxFold i s a Source #
Obtain an IxFold
by lifting an operation that returns a
FoldableWithIndex
result.
This can be useful to lift operations from Data.List
and elsewhere into an
IxFold
.
>>>
itoListOf (ifolding words) "how are you"
[(0,"how"),(1,"are"),(2,"you")]
ifoldring :: (forall f. Applicative f => (i -> a -> f u -> f u) -> f v -> s -> f w) -> IxFold i s a Source #
Additional elimination forms
iheadOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> s -> Maybe (i, a) Source #
Retrieve the first entry of an IxFold
along with its index.
>>>
iheadOf ifolded [1..10]
Just (0,1)
ilastOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> s -> Maybe (i, a) Source #
Retrieve the last entry of an IxFold
along with its index.
>>>
ilastOf ifolded [1..10]
Just (9,10)
ianyOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> Bool) -> s -> Bool Source #
iallOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> Bool) -> s -> Bool Source #
inoneOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> Bool) -> s -> Bool Source #
ifindOf :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> Bool) -> s -> Maybe (i, a) Source #
The ifindOf
function takes an IxFold
, a predicate that is also supplied
the index, a structure and returns the left-most element of the structure
along with its index matching the predicate, or Nothing
if there is no such
element.
When you don't need access to the index then findOf
is more flexible in
what it accepts.
ifindMOf :: (Is k A_Fold, Monad m, is `HasSingleIndex` i) => Optic' k is s a -> (i -> a -> m Bool) -> s -> m (Maybe (i, a)) Source #
The ifindMOf
function takes an IxFold
, a monadic predicate that is also
supplied the index, a structure and returns in the monad the left-most
element of the structure matching the predicate, or Nothing
if there is no
such element.
When you don't need access to the index then findMOf
is more flexible in
what it accepts.
Combinators
ipre :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> IxAffineFold i s a Source #
Convert an indexed fold to an IxAffineFold
that visits the first element
of the original fold.
For the traversal version see isingular
.
ifiltered :: (Is k A_Fold, is `HasSingleIndex` i) => (i -> a -> Bool) -> Optic' k is s a -> IxFold i s a Source #
Filter results of an IxFold
that don't satisfy a predicate.
>>>
toListOf (ifolded %& ifiltered (>)) [3,2,1,0]
[1,0]
ibackwards_ :: (Is k A_Fold, is `HasSingleIndex` i) => Optic' k is s a -> IxFold i s a Source #
This allows you to traverse the elements of an IxFold
in the opposite
order.
Monoid structures
IxFold
admits (at least) two monoid structures:
isumming
concatenates results from both folds.ifailing
returns results from the second fold only if the first returns no results.
In both cases, the identity element of the monoid is
ignored
, which returns no results.
There is no Semigroup
or Monoid
instance for IxFold
, because there is
not a unique choice of monoid to use, and the (<>
) operator could not be
used to combine optics of different kinds.
isumming :: (Is k A_Fold, Is l A_Fold, is1 `HasSingleIndex` i, is2 `HasSingleIndex` i) => Optic' k is1 s a -> Optic' l is2 s a -> IxFold i s a infixr 6 Source #
ifailing :: (Is k A_Fold, Is l A_Fold, is1 `HasSingleIndex` i, is2 `HasSingleIndex` i) => Optic' k is1 s a -> Optic' l is2 s a -> IxFold i s a infixl 3 Source #
Try the first IxFold
. If it returns no entries, try the second one.
>>>
itoListOf (_1 % ifolded `ifailing` _2 % ifolded) (["a"], ["b","c"])
[(0,"a")]>>>
itoListOf (_1 % ifolded `ifailing` _2 % ifolded) ([], ["b","c"])
[(0,"b"),(1,"c")]
Subtyping
data A_Fold :: OpticKind Source #
Tag for a fold.
Instances
Re-exports
class Foldable f => FoldableWithIndex i (f :: Type -> Type) | f -> i where #
A container that supports folding with an additional index.
Nothing
ifoldMap :: Monoid m => (i -> a -> m) -> f a -> m #
Fold a container by mapping value to an arbitrary Monoid
with access to the index i
.
When you don't need access to the index then foldMap
is more flexible in what it accepts.
foldMap
≡ifoldMap
.
const
ifoldMap' :: Monoid m => (i -> a -> m) -> f a -> m #
A variant of ifoldMap
that is strict in the accumulator.
When you don't need access to the index then foldMap'
is more flexible in what it accepts.
foldMap'
≡ifoldMap'
.
const
ifoldr :: (i -> a -> b -> b) -> b -> f a -> b #
Right-associative fold of an indexed container with access to the index i
.
When you don't need access to the index then foldr
is more flexible in what it accepts.
foldr
≡ifoldr
.
const
ifoldl :: (i -> b -> a -> b) -> b -> f a -> b #
Left-associative fold of an indexed container with access to the index i
.
When you don't need access to the index then foldl
is more flexible in what it accepts.
foldl
≡ifoldl
.
const
Instances
FoldableWithIndex () Identity | |
Defined in WithIndex | |
FoldableWithIndex () Par1 | |
FoldableWithIndex () Maybe | |
FoldableWithIndex Int ZipList | |
Defined in WithIndex | |
FoldableWithIndex Int IntMap | |
Defined in WithIndex | |
FoldableWithIndex Int Seq | |
FoldableWithIndex Int NonEmpty | |
Defined in WithIndex | |
FoldableWithIndex Int [] | |
FoldableWithIndex Void (Proxy :: Type -> Type) | |
Defined in WithIndex | |
FoldableWithIndex Void (U1 :: Type -> Type) | |
FoldableWithIndex Void (V1 :: Type -> Type) | |
Ix i => FoldableWithIndex i (Array i) | |
FoldableWithIndex k (Map k) | |
FoldableWithIndex k ((,) k) | |
FoldableWithIndex Void (Const e :: Type -> Type) | |
Defined in WithIndex | |
FoldableWithIndex Void (Constant e :: Type -> Type) | |
Defined in WithIndex ifoldMap :: Monoid m => (Void -> a -> m) -> Constant e a -> m # ifoldMap' :: Monoid m => (Void -> a -> m) -> Constant e a -> m # ifoldr :: (Void -> a -> b -> b) -> b -> Constant e a -> b # ifoldl :: (Void -> b -> a -> b) -> b -> Constant e a -> b # ifoldr' :: (Void -> a -> b -> b) -> b -> Constant e a -> b # ifoldl' :: (Void -> b -> a -> b) -> b -> Constant e a -> b # | |
FoldableWithIndex i f => FoldableWithIndex i (Rec1 f) | |
FoldableWithIndex i f => FoldableWithIndex i (Backwards f) | |
Defined in WithIndex | |
FoldableWithIndex i m => FoldableWithIndex i (IdentityT m) | |
Defined in WithIndex ifoldMap :: Monoid m0 => (i -> a -> m0) -> IdentityT m a -> m0 # ifoldMap' :: Monoid m0 => (i -> a -> m0) -> IdentityT m a -> m0 # ifoldr :: (i -> a -> b -> b) -> b -> IdentityT m a -> b # ifoldl :: (i -> b -> a -> b) -> b -> IdentityT m a -> b # | |
FoldableWithIndex i f => FoldableWithIndex i (Reverse f) | |
Defined in WithIndex | |
FoldableWithIndex Void (K1 i c :: Type -> Type) | |
Defined in WithIndex | |
FoldableWithIndex [Int] Tree | |
Defined in WithIndex | |
(FoldableWithIndex i f, FoldableWithIndex j g) => FoldableWithIndex (Either i j) (Product f g) | |
Defined in WithIndex ifoldMap :: Monoid m => (Either i j -> a -> m) -> Product f g a -> m # ifoldMap' :: Monoid m => (Either i j -> a -> m) -> Product f g a -> m # ifoldr :: (Either i j -> a -> b -> b) -> b -> Product f g a -> b # ifoldl :: (Either i j -> b -> a -> b) -> b -> Product f g a -> b # ifoldr' :: (Either i j -> a -> b -> b) -> b -> Product f g a -> b # ifoldl' :: (Either i j -> b -> a -> b) -> b -> Product f g a -> b # | |
(FoldableWithIndex i f, FoldableWithIndex j g) => FoldableWithIndex (Either i j) (Sum f g) | |
Defined in WithIndex ifoldMap :: Monoid m => (Either i j -> a -> m) -> Sum f g a -> m # ifoldMap' :: Monoid m => (Either i j -> a -> m) -> Sum f g a -> m # ifoldr :: (Either i j -> a -> b -> b) -> b -> Sum f g a -> b # ifoldl :: (Either i j -> b -> a -> b) -> b -> Sum f g a -> b # ifoldr' :: (Either i j -> a -> b -> b) -> b -> Sum f g a -> b # ifoldl' :: (Either i j -> b -> a -> b) -> b -> Sum f g a -> b # | |
(FoldableWithIndex i f, FoldableWithIndex j g) => FoldableWithIndex (Either i j) (f :*: g) | |
Defined in WithIndex ifoldMap :: Monoid m => (Either i j -> a -> m) -> (f :*: g) a -> m # ifoldMap' :: Monoid m => (Either i j -> a -> m) -> (f :*: g) a -> m # ifoldr :: (Either i j -> a -> b -> b) -> b -> (f :*: g) a -> b # ifoldl :: (Either i j -> b -> a -> b) -> b -> (f :*: g) a -> b # ifoldr' :: (Either i j -> a -> b -> b) -> b -> (f :*: g) a -> b # ifoldl' :: (Either i j -> b -> a -> b) -> b -> (f :*: g) a -> b # | |
(FoldableWithIndex i f, FoldableWithIndex j g) => FoldableWithIndex (Either i j) (f :+: g) | |
Defined in WithIndex ifoldMap :: Monoid m => (Either i j -> a -> m) -> (f :+: g) a -> m # ifoldMap' :: Monoid m => (Either i j -> a -> m) -> (f :+: g) a -> m # ifoldr :: (Either i j -> a -> b -> b) -> b -> (f :+: g) a -> b # ifoldl :: (Either i j -> b -> a -> b) -> b -> (f :+: g) a -> b # ifoldr' :: (Either i j -> a -> b -> b) -> b -> (f :+: g) a -> b # ifoldl' :: (Either i j -> b -> a -> b) -> b -> (f :+: g) a -> b # | |
(FoldableWithIndex i f, FoldableWithIndex j g) => FoldableWithIndex (i, j) (Compose f g) | |
Defined in WithIndex ifoldMap :: Monoid m => ((i, j) -> a -> m) -> Compose f g a -> m # ifoldMap' :: Monoid m => ((i, j) -> a -> m) -> Compose f g a -> m # ifoldr :: ((i, j) -> a -> b -> b) -> b -> Compose f g a -> b # ifoldl :: ((i, j) -> b -> a -> b) -> b -> Compose f g a -> b # ifoldr' :: ((i, j) -> a -> b -> b) -> b -> Compose f g a -> b # ifoldl' :: ((i, j) -> b -> a -> b) -> b -> Compose f g a -> b # | |
(FoldableWithIndex i f, FoldableWithIndex j g) => FoldableWithIndex (i, j) (f :.: g) | |
Defined in WithIndex ifoldMap :: Monoid m => ((i, j) -> a -> m) -> (f :.: g) a -> m # ifoldMap' :: Monoid m => ((i, j) -> a -> m) -> (f :.: g) a -> m # ifoldr :: ((i, j) -> a -> b -> b) -> b -> (f :.: g) a -> b # ifoldl :: ((i, j) -> b -> a -> b) -> b -> (f :.: g) a -> b # ifoldr' :: ((i, j) -> a -> b -> b) -> b -> (f :.: g) a -> b # ifoldl' :: ((i, j) -> b -> a -> b) -> b -> (f :.: g) a -> b # |