Modulelens-5.3.5Haskell2010

Control.Lens.At

3 classes
5 values

Packagelens-5.3.5
Exports10
LanguageHaskell2010
LicenceBSD-2-Clause
SourceAt.hs

At

3 declarations

classclass Ixed m => At m where

At provides a Lens that can be used to read, write or delete the value associated with a key in a Map-like container on an ad hoc basis.

An instance of At should satisfy:

ix k ≡ at k . traverse

Methods

at :: Index m -> Lens' m (Maybe (IxValue m))
Example1 expression
```
>>> Map.fromList [(1,"world")] ^.at 1Just "world"
```
Example1 expression
```
>>> at 1 ?~ "hello" $ Map.emptyfromList [(1,"hello")]
```
Note: Map-like containers form a reasonable instance, but not Array-like ones, where you cannot satisfy the Lens laws.

Instances7At, …

At IntSetDefined in lens-5.3.5 · Control.Lens.At
Ord k => At (Set k)Defined in lens-5.3.5 · Control.Lens.At
At (IntMap a)Defined in lens-5.3.5 · Control.Lens.At
At (Maybe a)Defined in lens-5.3.5 · Control.Lens.At
(Eq k, Hashable k) => At (HashSet k)Defined in lens-5.3.5 · Control.Lens.At
Ord k => At (Map k a)Defined in lens-5.3.5 · Control.Lens.At
(Eq k, Hashable k) => At (HashMap k a)Defined in lens-5.3.5 · Control.Lens.At

valuesans :: At m => Index m -> m -> m

Delete the value associated with a key in a Map-like container

sans k = at k .~ Nothing

valueiat :: At m => Index m -> IndexedLens' (Index m) m (Maybe (IxValue m))

An indexed version of at.

Example1 expression

>>> Map.fromList [(1,"world")] ^@. iat 1(1,Just "world")

Example1 expression

>>> iat 1 %@~ (\i x -> if odd i then Just "hello" else Nothing) $ Map.emptyfromList [(1,"hello")]

Example1 expression

>>> iat 2 %@~ (\i x -> if odd i then Just "hello" else Nothing) $ Map.emptyfromList []

Ixed

5 declarations

familytype family Index s

Instances33Index, …

type Index ByteString = IntDefined in lens-5.3.5 · Control.Lens.At
type Index ByteString = Int64Defined in lens-5.3.5 · Control.Lens.At
type Index IntSet = IntDefined in lens-5.3.5 · Control.Lens.At
type Index Text = IntDefined in lens-5.3.5 · Control.Lens.At
type Index Text = Int64Defined in lens-5.3.5 · Control.Lens.At
type Index (UArray i e) = iDefined in lens-5.3.5 · Control.Lens.At
type Index (Complex a) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (IntMap a) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (Map k a) = kDefined in lens-5.3.5 · Control.Lens.At
type Index (Seq a) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (Set a) = aDefined in lens-5.3.5 · Control.Lens.At
type Index (Tree a) = [Int]Defined in lens-5.3.5 · Control.Lens.At
type Index (Array i e) = iDefined in lens-5.3.5 · Control.Lens.At
type Index (NonEmpty a) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (Identity a) = ()Defined in lens-5.3.5 · Control.Lens.At
type Index (Maybe a) = ()Defined in lens-5.3.5 · Control.Lens.At
type Index (HashMap k a) = kDefined in lens-5.3.5 · Control.Lens.At
type Index (HashSet a) = aDefined in lens-5.3.5 · Control.Lens.At
type Index (Vector a) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (Vector a) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (Vector a) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (Vector a) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (Vector a) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (a, b) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (a, b, c) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (a, b, c, d) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (a, b, c, d, e) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (a, b, c, d, e, f) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (a, b, c, d, e, f, g) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (a, b, c, d, e, f, g, h) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (a, b, c, d, e, f, g, h, i) = IntDefined in lens-5.3.5 · Control.Lens.At
type Index (e -> a) = eDefined in lens-5.3.5 · Control.Lens.At
type Index [a] = IntDefined in lens-5.3.5 · Control.Lens.At

familytype family IxValue m

This provides a common notion of a value at an index that is shared by both Ixed and At.

Instances32IxValue, …

type IxValue ByteString = Word8Defined in lens-5.3.5 · Control.Lens.At
type IxValue ByteString = Word8Defined in lens-5.3.5 · Control.Lens.At
type IxValue IntSet = ()Defined in lens-5.3.5 · Control.Lens.At
type IxValue Text = CharDefined in lens-5.3.5 · Control.Lens.At
type IxValue Text = CharDefined in lens-5.3.5 · Control.Lens.At
type IxValue (UArray i e) = eDefined in lens-5.3.5 · Control.Lens.At
type IxValue (IntMap a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue (Map k a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue (Seq a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue (Set k) = ()Defined in lens-5.3.5 · Control.Lens.At
type IxValue (Tree a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue (Array i e) = eDefined in lens-5.3.5 · Control.Lens.At
type IxValue (NonEmpty a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue (Identity a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue (Maybe a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue (HashMap k a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue (HashSet k) = ()Defined in lens-5.3.5 · Control.Lens.At
type IxValue (Vector a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue (Vector a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue (Vector a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue (Vector a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue (Vector a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue (a, a2) = aDefined in lens-5.3.5 · Control.Lens.At
```
ix :: Int -> Traversal' (a,a) a
```
type IxValue (a, a2, a3) = aDefined in lens-5.3.5 · Control.Lens.At
```
ix :: Int -> Traversal' (a,a,a) a
```
type IxValue (a, a2, a3, a4) = aDefined in lens-5.3.5 · Control.Lens.At
```
ix :: Int -> Traversal' (a,a,a,a) a
```
type IxValue (a, a2, a3, a4, a5) = aDefined in lens-5.3.5 · Control.Lens.At
```
ix :: Int -> Traversal' (a,a,a,a,a) a
```
type IxValue (a, a2, a3, a4, a5, a6) = aDefined in lens-5.3.5 · Control.Lens.At
```
ix :: Int -> Traversal' (a,a,a,a,a,a) a
```
type IxValue (a, a2, a3, a4, a5, a6, a7) = aDefined in lens-5.3.5 · Control.Lens.At
```
ix :: Int -> Traversal' (a,a,a,a,a,a,a) a
```
type IxValue (a, a2, a3, a4, a5, a6, a7, a8) = aDefined in lens-5.3.5 · Control.Lens.At
```
ix :: Int -> Traversal' (a,a,a,a,a,a,a,a) a
```
type IxValue (a, a2, a3, a4, a5, a6, a7, a8, a9) = aDefined in lens-5.3.5 · Control.Lens.At
```
ix :: Int -> Traversal' (a,a,a,a,a,a,a,a,a) a
```
type IxValue (e -> a) = aDefined in lens-5.3.5 · Control.Lens.At
type IxValue [a] = aDefined in lens-5.3.5 · Control.Lens.At

classclass Ixed m where

Provides a simple Traversal lets you traverse the value at a given key in a Map or element at an ordinal position in a list or Seq.

Methods

ix :: Index m -> Traversal' m (IxValue m)
NB: Setting the value of this Traversal will only set the value in at if it is already present.
If you want to be able to insert missing values, you want at.
Example1 expression
```
>>> Seq.fromList [a,b,c,d] & ix 2 %~ ffromList [a,b,f c,d]
```
Example1 expression
```
>>> Seq.fromList [a,b,c,d] & ix 2 .~ efromList [a,b,e,d]
```
Example1 expression
```
>>> Seq.fromList [a,b,c,d] ^? ix 2Just c
```
Example1 expression
```
>>> Seq.fromList [] ^? ix 2Nothing
```

Instances32Ixed, …

Ixed ByteStringDefined in lens-5.3.5 · Control.Lens.At
Ixed ByteStringDefined in lens-5.3.5 · Control.Lens.At
Ixed IntSetDefined in lens-5.3.5 · Control.Lens.At
Ixed TextDefined in lens-5.3.5 · Control.Lens.At
Ixed TextDefined in lens-5.3.5 · Control.Lens.At
Storable a => Ixed (Vector a)Defined in lens-5.3.5 · Control.Lens.At
Ord k => Ixed (Set k)Defined in lens-5.3.5 · Control.Lens.At
Ixed (IntMap a)Defined in lens-5.3.5 · Control.Lens.At
Ixed (Seq a)Defined in lens-5.3.5 · Control.Lens.At
Ixed (Tree a)Defined in lens-5.3.5 · Control.Lens.At
Ixed (NonEmpty a)Defined in lens-5.3.5 · Control.Lens.At
Ixed (Identity a)Defined in lens-5.3.5 · Control.Lens.At
Ixed (Maybe a)Defined in lens-5.3.5 · Control.Lens.At
Ixed (Vector a)Defined in lens-5.3.5 · Control.Lens.At
Ixed (Vector a)Defined in lens-5.3.5 · Control.Lens.At
Ixed [a]Defined in lens-5.3.5 · Control.Lens.At
Prim a => Ixed (Vector a)Defined in lens-5.3.5 · Control.Lens.At
Unbox a => Ixed (Vector a)Defined in lens-5.3.5 · Control.Lens.At
(Eq k, Hashable k) => Ixed (HashSet k)Defined in lens-5.3.5 · Control.Lens.At

Ix i => Ixed (Array i e)Defined in lens-5.3.5 · Control.Lens.At

arr ! i ≡ arr ^. ix i
arr // [(i,e)] ≡ ix i .~ e $ arr

Eq e => Ixed (e -> a)Defined in lens-5.3.5 · Control.Lens.At
Ord k => Ixed (Map k a)Defined in lens-5.3.5 · Control.Lens.At
(IArray UArray e, Ix i) => Ixed (UArray i e)Defined in lens-5.3.5 · Control.Lens.At
```
arr ! i ≡ arr ^. ix i
arr // [(i,e)] ≡ ix i .~ e $ arr
```
(Eq k, Hashable k) => Ixed (HashMap k a)Defined in lens-5.3.5 · Control.Lens.At
a ~ a2 => Ixed (a, a2)Defined in lens-5.3.5 · Control.Lens.At
(a ~ a2, a ~ a3) => Ixed (a, a2, a3)Defined in lens-5.3.5 · Control.Lens.At
(a ~ a2, a ~ a3, a ~ a4) => Ixed (a, a2, a3, a4)Defined in lens-5.3.5 · Control.Lens.At
(a ~ a2, a ~ a3, a ~ a4, a ~ a5) => Ixed (a, a2, a3, a4, a5)Defined in lens-5.3.5 · Control.Lens.At
(a ~ a2, a ~ a3, a ~ a4, a ~ a5, a ~ a6) => Ixed (a, a2, a3, a4, a5, a6)Defined in lens-5.3.5 · Control.Lens.At
(a ~ a2, a ~ a3, a ~ a4, a ~ a5, a ~ a6, a ~ a7) => Ixed (a, a2, a3, a4, a5, a6, a7)Defined in lens-5.3.5 · Control.Lens.At
(a ~ a2, a ~ a3, a ~ a4, a ~ a5, a ~ a6, a ~ a7, a ~ a8) => Ixed (a, a2, a3, a4, a5, a6, a7, a8)Defined in lens-5.3.5 · Control.Lens.At
(a ~ a2, a ~ a3, a ~ a4, a ~ a5, a ~ a6, a ~ a7, a ~ a8, a ~ a9) => Ixed (a, a2, a3, a4, a5, a6, a7, a8, a9)Defined in lens-5.3.5 · Control.Lens.At

valueixAt :: At m => Index m -> Traversal' m (IxValue m)

A definition of ix for types with an At instance. This is the default if you don't specify a definition for ix.

valueiix :: Ixed m => Index m -> IndexedTraversal' (Index m) m (IxValue m)

An indexed version of ix.

Example1 expression

>>> Seq.fromList [a,b,c,d] & iix 2 %@~ f'fromList [a,b,f' 2 c,d]

Example1 expression

>>> Seq.fromList [a,b,c,d] & iix 2 .@~ hfromList [a,b,h 2,d]

Example1 expression

>>> Seq.fromList [a,b,c,d] ^@? iix 2Just (2,c)

Example1 expression

>>> Seq.fromList [] ^@? iix 2Nothing

Contains

2 declarations

classclass Contains m where

This class provides a simple Lens that lets you view (and modify) information about whether or not a container contains a given Index.

Methods

contains :: Index m -> Lens' m Bool

Example1 expression

>>> IntSet.fromList [1,2,3,4] ^. contains 3True

Example1 expression

>>> IntSet.fromList [1,2,3,4] ^. contains 5False

Example1 expression

>>> IntSet.fromList [1,2,3,4] & contains 3 .~ FalsefromList [1,2,4]

Instances3Contains

Contains IntSetDefined in lens-5.3.5 · Control.Lens.At
Ord a => Contains (Set a)Defined in lens-5.3.5 · Control.Lens.At
(Eq a, Hashable a) => Contains (HashSet a)Defined in lens-5.3.5 · Control.Lens.At

valueicontains :: Contains m => Index m -> IndexedLens' (Index m) m Bool

An indexed version of contains.

Example1 expression

>>> IntSet.fromList [1,2,3,4] ^@. icontains 3(3,True)

Example1 expression

>>> IntSet.fromList [1,2,3,4] ^@. icontains 5(5,False)

Example1 expression

>>> IntSet.fromList [1,2,3,4] & icontains 3 %@~ \i x -> if odd i then not x else xfromList [1,2,4]

Example1 expression

>>> IntSet.fromList [1,2,3,4] & icontains 3 %@~ \i x -> if even i then not x else xfromList [1,2,3,4]