Safe Haskell	Safe
Language	Haskell2010

Data.Traversable.WithIndex

Contents

Indexed Traversables
Indexed Traversable Combinators
Default implementations

Description

Indexed Traversables

Synopsis

class (FunctorWithIndex i t, FoldableWithIndex i t, Traversable t) => TraversableWithIndex i t | t -> i where
- itraverse :: Applicative f => (i -> a -> f b) -> t a -> f (t b)
ifor :: (TraversableWithIndex i t, Applicative f) => t a -> (i -> a -> f b) -> f (t b)
imapM :: (TraversableWithIndex i t, Monad m) => (i -> a -> m b) -> t a -> m (t b)
iforM :: (TraversableWithIndex i t, Monad m) => t a -> (i -> a -> m b) -> m (t b)
imapAccumR :: TraversableWithIndex i t => (i -> s -> a -> (s, b)) -> s -> t a -> (s, t b)
imapAccumL :: TraversableWithIndex i t => (i -> s -> a -> (s, b)) -> s -> t a -> (s, t b)
imapDefault :: TraversableWithIndex i f => (i -> a -> b) -> f a -> f b
ifoldMapDefault :: (TraversableWithIndex i f, Monoid m) => (i -> a -> m) -> f a -> m

Indexed Traversables

class (FunctorWithIndex i t, FoldableWithIndex i t, Traversable t) => TraversableWithIndex i t | t -> i where Source #

A Traversable with an additional index.

An instance must satisfy a (modified) form of the Traversable laws:

itraverse  (const Identity ) ≡ Identity 
fmap  (itraverse  f) .  itraverse  g ≡ getCompose  .  itraverse  (\i -> Compose  .  fmap  (f i) .  g i)

Minimal complete definition

Nothing

Methods

itraverse :: Applicative f => (i -> a -> f b) -> t a -> f (t b) Source #

Traverse an indexed container.

itraverse  ≡ itraverseOf itraversed

default itraverse :: (i ~ Int, Applicative f) => (i -> a -> f b) -> t a -> f (t b) Source #

Instances

Instances details

TraversableWithIndex Int [] Source #

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Methods

itraverse :: Applicative f => (Int -> a -> f b) -> [a] -> f [b] Source #

TraversableWithIndex Int ZipList Source #

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Methods

itraverse :: Applicative f => (Int -> a -> f b) -> ZipList a -> f (ZipList b) Source #

TraversableWithIndex Int NonEmpty Source #

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Methods

itraverse :: Applicative f => (Int -> a -> f b) -> NonEmpty a -> f (NonEmpty b) Source #

TraversableWithIndex Int IntMap Source #

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Methods

itraverse :: Applicative f => (Int -> a -> f b) -> IntMap a -> f (IntMap b) Source #

TraversableWithIndex Int Seq Source #

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Methods

itraverse :: Applicative f => (Int -> a -> f b) -> Seq a -> f (Seq b) Source #

TraversableWithIndex () Maybe Source #

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Methods

itraverse :: Applicative f => (() -> a -> f b) -> Maybe a -> f (Maybe b) Source #

TraversableWithIndex () Par1 Source #

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Methods

itraverse :: Applicative f => (() -> a -> f b) -> Par1 a -> f (Par1 b) Source #

TraversableWithIndex () Identity Source #

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Methods

itraverse :: Applicative f => (() -> a -> f b) -> Identity a -> f (Identity b) Source #

TraversableWithIndex k (Map k) Source #

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Methods

itraverse :: Applicative f => (k -> a -> f b) -> Map k a -> f (Map k b) Source #

Ix i => TraversableWithIndex i (Array i) Source #

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Methods

itraverse :: Applicative f => (i -> a -> f b) -> Array i a -> f (Array i b) Source #

TraversableWithIndex k ((,) k) Source #

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Methods

itraverse :: Applicative f => (k -> a -> f b) -> (k, a) -> f (k, b) Source #

TraversableWithIndex Void (V1 :: Type -> Type) Source #

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Methods

itraverse :: Applicative f => (Void -> a -> f b) -> V1 a -> f (V1 b) Source #

TraversableWithIndex Void (U1 :: Type -> Type) Source #

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Methods

itraverse :: Applicative f => (Void -> a -> f b) -> U1 a -> f (U1 b) Source #

TraversableWithIndex Void (Proxy :: Type -> Type) Source #

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Methods

itraverse :: Applicative f => (Void -> a -> f b) -> Proxy a -> f (Proxy b) Source #

TraversableWithIndex i f => TraversableWithIndex i (Rec1 f) Source #

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Methods

itraverse :: Applicative f0 => (i -> a -> f0 b) -> Rec1 f a -> f0 (Rec1 f b) Source #

TraversableWithIndex i f => TraversableWithIndex i (Reverse f) Source #

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Methods

itraverse :: Applicative f0 => (i -> a -> f0 b) -> Reverse f a -> f0 (Reverse f b) Source #

TraversableWithIndex i f => TraversableWithIndex i (Backwards f) Source #

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Methods

itraverse :: Applicative f0 => (i -> a -> f0 b) -> Backwards f a -> f0 (Backwards f b) Source #

TraversableWithIndex i m => TraversableWithIndex i (IdentityT m) Source #

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Methods

itraverse :: Applicative f => (i -> a -> f b) -> IdentityT m a -> f (IdentityT m b) Source #

TraversableWithIndex Void (Const e :: Type -> Type) Source #

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Methods

itraverse :: Applicative f => (Void -> a -> f b) -> Const e a -> f (Const e b) Source #

TraversableWithIndex Void (Constant e :: Type -> Type) Source #

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Methods

itraverse :: Applicative f => (Void -> a -> f b) -> Constant e a -> f (Constant e b) Source #

TraversableWithIndex Void (K1 i c :: Type -> Type) Source #

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itraverse :: Applicative f => (Void -> a -> f b) -> K1 i c a -> f (K1 i c b) Source #

TraversableWithIndex [Int] Tree Source #

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Methods

itraverse :: Applicative f => ([Int] -> a -> f b) -> Tree a -> f (Tree b) Source #

(TraversableWithIndex i f, TraversableWithIndex j g) => TraversableWithIndex (Either i j) (f :+: g) Source #

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Methods

itraverse :: Applicative f0 => (Either i j -> a -> f0 b) -> (f :+: g) a -> f0 ((f :+: g) b) Source #

(TraversableWithIndex i f, TraversableWithIndex j g) => TraversableWithIndex (Either i j) (f :*: g) Source #

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Defined in WithIndex

Methods

itraverse :: Applicative f0 => (Either i j -> a -> f0 b) -> (f :*: g) a -> f0 ((f :*: g) b) Source #

(TraversableWithIndex i f, TraversableWithIndex j g) => TraversableWithIndex (Either i j) (Product f g) Source #

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Defined in WithIndex

Methods

itraverse :: Applicative f0 => (Either i j -> a -> f0 b) -> Product f g a -> f0 (Product f g b) Source #

(TraversableWithIndex i f, TraversableWithIndex j g) => TraversableWithIndex (Either i j) (Sum f g) Source #

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Defined in WithIndex

Methods

itraverse :: Applicative f0 => (Either i j -> a -> f0 b) -> Sum f g a -> f0 (Sum f g b) Source #

(TraversableWithIndex i f, TraversableWithIndex j g) => TraversableWithIndex (i, j) (f :.: g) Source #

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Defined in WithIndex

Methods

itraverse :: Applicative f0 => ((i, j) -> a -> f0 b) -> (f :.: g) a -> f0 ((f :.: g) b) Source #

(TraversableWithIndex i f, TraversableWithIndex j g) => TraversableWithIndex (i, j) (Compose f g) Source #

Instance details

Defined in WithIndex

Methods

itraverse :: Applicative f0 => ((i, j) -> a -> f0 b) -> Compose f g a -> f0 (Compose f g b) Source #

Indexed Traversable Combinators

ifor :: (TraversableWithIndex i t, Applicative f) => t a -> (i -> a -> f b) -> f (t b) Source #

Traverse with an index (and the arguments flipped).

for a ≡ ifor  a . const
ifor  ≡ flip  itraverse

imapM :: (TraversableWithIndex i t, Monad m) => (i -> a -> m b) -> t a -> m (t b) Source #

Map each element of a structure to a monadic action, evaluate these actions from left to right, and collect the results, with access the index.

When you don't need access to the index mapM is more liberal in what it can accept.

mapM ≡ imapM  . const

iforM :: (TraversableWithIndex i t, Monad m) => t a -> (i -> a -> m b) -> m (t b) Source #

Map each element of a structure to a monadic action, evaluate these actions from left to right, and collect the results, with access its position (and the arguments flipped).

forM a ≡ iforM  a . const
iforM  ≡ flip  imapM

imapAccumR :: TraversableWithIndex i t => (i -> s -> a -> (s, b)) -> s -> t a -> (s, t b) Source #

Generalizes mapAccumR to add access to the index.

imapAccumR accumulates state from right to left.

mapAccumR  ≡ imapAccumR  . const

imapAccumL :: TraversableWithIndex i t => (i -> s -> a -> (s, b)) -> s -> t a -> (s, t b) Source #

Generalizes mapAccumL to add access to the index.

imapAccumL accumulates state from left to right.

mapAccumL  ≡ imapAccumL  . const

Default implementations

imapDefault :: TraversableWithIndex i f => (i -> a -> b) -> f a -> f b Source #

ifoldMapDefault :: (TraversableWithIndex i f, Monoid m) => (i -> a -> m) -> f a -> m Source #