Lens (FSharpPlus)

Lens Module

Namespace: FSharpPlus
Assembly: FSharpPlus.dll

Lens functions and operators

Nested modules

Modules	Description
Array
IReadOnlyDictionary
List
Map
Set

Functions and values

Function or value	Description
`lens %-> updater` Full Usage: `lens %-> updater` Parameters: lens : `('a -> Identity<'b>) -> 's -> Identity<'t>` - The lens. updater : `'a -> 'b` - A function that converts the value we want to write in the part targeted by the lens. Returns: `'s -> 't` The new object with the value modified.	Update a value in a lens. Same as ``over``. lens : `('a -> Identity<'b>) -> 's -> Identity<'t>` The lens. updater : `'a -> 'b` A function that converts the value we want to write in the part targeted by the lens. Returns: `'s -> 't` The new object with the value modified.
`lens .-> value` Full Usage: `lens .-> value` Parameters: lens : `('a -> Identity<'b>) -> 's -> Identity<'t>` - The lens. value : `'b` - The value we want to write in the part targeted by the lens. Returns: `'s -> 't` The new object with the value modified.	Write to a lens. Same as ``setl``. lens : `('a -> Identity<'b>) -> 's -> Identity<'t>` The lens. value : `'b` The value we want to write in the part targeted by the lens. Returns: `'s -> 't` The new object with the value modified.
`x <&> f` Full Usage: `x <&> f` Parameters: x : `^F<'t>` - The functor. f : `'t -> 'u` - The mapper function. Returns: `'F<'u>` The mapped Functor. Modifiers: inline Type parameters: ^F<'t>, 't, 'u, 'F<'u>	An infix flipped map, restricted to non-primitive types. x : `^F<'t>` The functor. f : `'t -> 'u` The mapper function. Returns: `'F<'u>` The mapped Functor.
`source ^. lens` Full Usage: `source ^. lens` Parameters: source : `'s` - The object. lens : `('a -> Const<'a, 'b>) -> 's -> Const<'c, 't>` - The lens. Returns: `'c` The part the lens is targeting.	Read from a lens. Same as ``view`` but with the arguments flipped. source : `'s` The object. lens : `('a -> Const<'a, 'b>) -> 's -> Const<'c, 't>` The lens. Returns: `'c` The part the lens is targeting.
`s ^.. l` Full Usage: `s ^.. l` Parameters: s : `'a` l : `('b -> Const<Endo<'b list>, 'c>) -> 'a -> Const<Endo<'d list>, 'e>` Returns: `'d list`	Extract a list of the targets of a Fold. Same as ``toListOf`` but with the arguments flipped. s : `'a` l : `('b -> Const<Endo<'b list>, 'c>) -> 'a -> Const<Endo<'d list>, 'e>` Returns: `'d list`
`source ^? prism` Full Usage: `source ^? prism` Parameters: source : `'s` - The object. prism : `('a -> Const<First<'a>, 'b>) -> 's -> Const<First<'c>, 't>` - The prism. Returns: `'c option` The value (if any) the prism is targeting.	Retrieve the first value targeted by a Prism, Fold or Traversal (or Some result from a Getter or Lens). Same as ``preview`` but with the arguments flipped. source : `'s` The object. prism : `('a -> Const<First<'a>, 'b>) -> 's -> Const<First<'c>, 't>` The prism. Returns: `'c option` The value (if any) the prism is targeting.
`_1 f t` Full Usage: `_1 f t` Parameters: f : `'a -> ^b` t : `^f` Returns: `'e` Modifiers: inline	Lens for the first element of a tuple f : `'a -> ^b` t : `^f` Returns: `'e`
`_2 f t` Full Usage: `_2 f t` Parameters: f : `'a -> ^b` t : `^f` Returns: `'e` Modifiers: inline	Lens for the second element of a tuple f : `'a -> ^b` t : `^f` Returns: `'e`
`_3 f t` Full Usage: `_3 f t` Parameters: f : `'a -> ^b` t : `^f` Returns: `'e` Modifiers: inline	Lens for the third element of a tuple f : `'a -> ^b` t : `^f` Returns: `'e`
`_4 f t` Full Usage: `_4 f t` Parameters: f : `'a -> ^b` t : `^f` Returns: `'e` Modifiers: inline	Lens for the fourth element of a tuple f : `'a -> ^b` t : `^f` Returns: `'e`
`_5 f t` Full Usage: `_5 f t` Parameters: f : `'a -> ^b` t : `^f` Returns: `'e` Modifiers: inline	Lens for the fifth element of a tuple f : `'a -> ^b` t : `^f` Returns: `'e`
`_Error x` Full Usage: `_Error x` Parameters: x : `'a -> ^b` Returns: `Result<'d, 'a> -> ^e` Modifiers: inline	Prism providing a Traversal for targeting the 'Error' part of a Result<'T,'Error> x : `'a -> ^b` Returns: `Result<'d, 'a> -> ^e`
`_None x` Full Usage: `_None x` Parameters: x : `unit -> ^a` Returns: `'c option -> ^d` Modifiers: inline	Prism providing a Traversal for targeting the 'None' part of an Option<'T> x : `unit -> ^a` Returns: `'c option -> ^d`
`_Ok x` Full Usage: `_Ok x` Parameters: x : `'a -> ^b` Returns: `Result<'a, 'd> -> ^e` Modifiers: inline	Prism providing a Traversal for targeting the 'Ok' part of a Result<'T,'Error> x : `'a -> ^b` Returns: `Result<'a, 'd> -> ^e`
`_Some x` Full Usage: `_Some x` Parameters: x : `'a -> ^b` Returns: `'a option -> ^d` Modifiers: inline	Prism providing a Traversal for targeting the 'Some' part of an Option<'T> x : `'a -> ^b` Returns: `'a option -> ^d`
`_all ref f s` Full Usage: `_all ref f s` Parameters: ref : `'a` f : `'a -> ^b` s : `^c` Returns: `^d` Modifiers: inline	ref : `'a` f : `'a -> ^b` s : `^c` Returns: `^d`
`allOf l f` Full Usage: `allOf l f` Parameters: l : `('a -> Const<All, 'b>) -> 'c -> Const<All, 'd>` f : `'a -> bool` Returns: `'c -> bool`	l : `('a -> Const<All, 'b>) -> 'c -> Const<All, 'd>` f : `'a -> bool` Returns: `'c -> bool`
`anyOf l f` Full Usage: `anyOf l f` Parameters: l : `('a -> Const<Any, 'b>) -> 'c -> Const<Any, 'd>` f : `'a -> bool` Returns: `'c -> bool`	l : `('a -> Const<Any, 'b>) -> 'c -> Const<Any, 'd>` f : `'a -> bool` Returns: `'c -> bool`
`both f (a, b)` Full Usage: `both f (a, b)` Parameters: f : `'a -> ^b` a : `'a` b : `'a` Returns: `^f` Modifiers: inline	f : `'a -> ^b` a : `'a` b : `'a` Returns: `^f`
`choosed p f s` Full Usage: `choosed p f s` Parameters: p : `'a -> 'b option` f : `'b -> ^c` s : `'a` Returns: `^c` Modifiers: inline	p : `'a -> 'b option` f : `'b -> ^c` s : `'a` Returns: `^c`
`choosing optic1 optic2 f _arg1` Full Usage: `choosing optic1 optic2 f _arg1` Parameters: optic1 : `('a -> 'F<'b>) -> 's1 -> ^F<'t1>` optic2 : `('a -> 'F<'b>) -> 's2 -> ^F<'t2>` f : `'a -> 'F<'b>` _arg1 : `Result<'s2, 's1>` Returns: `'F>` Modifiers: inline Type parameters: 's1, 't1, 's2, 't2, 'a, 'b, ^F<'t1>, ^F<'t2>, 'F<'b>, 'F<Result<'t2,'t1>>	Merge two lenses, getters, setters, folds or traversals. The first optic. The second optic. The free parameter. An optic for a Result which uses the first optic for the Ok and the second for the Error. optic1 : `('a -> 'F<'b>) -> 's1 -> ^F<'t1>` optic2 : `('a -> 'F<'b>) -> 's2 -> ^F<'t2>` f : `'a -> 'F<'b>` _arg1 : `Result<'s2, 's1>` Returns: `'F>`
`elemOf l` Full Usage: `elemOf l` Parameters: l : `('a -> Const<Any, 'b>) -> 'c -> Const<Any, 'd>` Returns: `'a -> 'c -> bool`	l : `('a -> Const<Any, 'b>) -> 'c -> Const<Any, 'd>` Returns: `'a -> 'c -> bool`
`filtered p f s` Full Usage: `filtered p f s` Parameters: p : `'a -> bool` f : `'a -> ^b` s : `'a` Returns: `^b` Modifiers: inline	p : `'a -> bool` f : `'a -> ^b` s : `'a` Returns: `^b`
`foldMapOf l f` Full Usage: `foldMapOf l f` Parameters: l : `('a -> Const<'b, 'c>) -> 'd -> Const<'e, 'f>` f : `'a -> 'b` Returns: `'d -> 'e`	l : `('a -> Const<'b, 'c>) -> 'd -> Const<'e, 'f>` f : `'a -> 'b` Returns: `'d -> 'e`
`foldOf l` Full Usage: `foldOf l` Parameters: l : `('a -> Const<'a, 'b>) -> 'c -> Const<'d, 'e>` Returns: `'c -> 'd`	l : `('a -> Const<'a, 'b>) -> 'c -> Const<'d, 'e>` Returns: `'c -> 'd`
`foldlOf l f z` Full Usage: `foldlOf l f z` Parameters: l : `('a -> Const<Dual<Endo<'b>>, 'c>) -> 'd -> Const<Dual<Endo<'e>>, 'f>` f : `'b -> 'a -> 'b` z : `'e` Returns: `'d -> 'e`	l : `('a -> Const<Dual<Endo<'b>>, 'c>) -> 'd -> Const<Dual<Endo<'e>>, 'f>` f : `'b -> 'a -> 'b` z : `'e` Returns: `'d -> 'e`
`foldrOf l f z` Full Usage: `foldrOf l f z` Parameters: l : `('a -> Const<Endo<'b>, 'c>) -> 'd -> Const<Endo<'e>, 'f>` f : `'a -> 'b -> 'b` z : `'e` Returns: `'d -> 'e`	l : `('a -> Const<Endo<'b>, 'c>) -> 'd -> Const<Endo<'e>, 'f>` f : `'a -> 'b -> 'b` z : `'e` Returns: `'d -> 'e`
`from' l` Full Usage: `from' l` Parameters: l : `Exchange<('a -> 'a), ('b -> Identity<'b>)> -> Exchange<('c -> 'd), ('e -> Identity<'f>)>` Returns: `^g -> ^h` Modifiers: inline	l : `Exchange<('a -> 'a), ('b -> Identity<'b>)> -> Exchange<('c -> 'd), ('e -> Identity<'f>)>` Returns: `^g -> ^h`
`iso func inv` Full Usage: `iso func inv` Parameters: func : `'s -> 'a` - The transform function. inv : `'b -> 't` - The inverse of the transform function. Returns: `^i -> ^j` The iso. Modifiers: inline Type parameters: 's, 'a, 'b, 't, ^i, ^j, ^k, 'l	Build an 'Iso' from a pair of inverse functions. func : `'s -> 'a` The transform function. inv : `'b -> 't` The inverse of the transform function. Returns: `^i -> ^j` The iso.
`items x` Full Usage: `items x` Parameters: x : `'a -> 'b` Returns: `^c -> ^d` Modifiers: inline	x : `'a -> 'b` Returns: `^c -> ^d`
`lens getter setter f s` Full Usage: `lens getter setter f s` Parameters: getter : `'s -> 'a` - The getter function. setter : `'s -> 'b -> 't` - The setter function, having as first parameter the object and second the value to set. f : `'a -> ^F<'b>` - The free parameter. s : `'s` - Returns: `'F<'t>` The lens. Modifiers: inline Type parameters: 's, 'a, 'b, 't, ^F<'b>, 'F<'t>	Build a 'Lens' from a getter and a setter. The lens should be assigned as an inline function of the free parameter, not a value, otherwise compiler will fail with a type constraint mismatch. getter : `'s -> 'a` The getter function. setter : `'s -> 'b -> 't` The setter function, having as first parameter the object and second the value to set. f : `'a -> ^F<'b>` The free parameter. s : `'s` Returns: `'F<'t>` The lens.
`mapping k` Full Usage: `mapping k` Parameters: k : `Exchange<('a -> 'a), ('b -> Identity<'b>)> -> Exchange<('c -> 'd), ('e -> Identity<'f>)>` Returns: `^g -> ^h` Modifiers: inline	k : `Exchange<('a -> 'a), ('b -> Identity<'b>)> -> Exchange<('c -> 'd), ('e -> Identity<'f>)>` Returns: `^g -> ^h`
`maximumOf l` Full Usage: `maximumOf l` Parameters: l : `('a -> Const<Dual<Endo<'a option>>, 'b>) -> 'c -> Const<Dual<Endo<'d option>>, 'e>` Returns: `'c -> 'd option`	Get the largest target of a Fold. l : `('a -> Const<Dual<Endo<'a option>>, 'b>) -> 'c -> Const<Dual<Endo<'d option>>, 'e>` Returns: `'c -> 'd option`
`minimumOf l` Full Usage: `minimumOf l` Parameters: l : `('a -> Const<Dual<Endo<'a option>>, 'b>) -> 'c -> Const<Dual<Endo<'d option>>, 'e>` Returns: `'c -> 'd option`	Get the smallest target of a Fold. l : `('a -> Const<Dual<Endo<'a option>>, 'b>) -> 'c -> Const<Dual<Endo<'d option>>, 'e>` Returns: `'c -> 'd option`
`non def f ma` Full Usage: `non def f ma` Parameters: def : `'a` f : `'a -> ^b` ma : `'a option` Returns: `'c` Modifiers: inline	Lens for the value inside an Option or the given default value if the Option is None. Works well when combined with Map._item def : `'a` f : `'a -> ^b` ma : `'a option` Returns: `'c`
`over lens f` Full Usage: `over lens f` Parameters: lens : `('a -> Identity<'b>) -> 'c -> Identity<'d>` - The lens. f : `'a -> 'b` - A function that converts the value we want to write in the part targeted by the lens. Returns: `'c -> 'd` The new object with the value modified.	Update a value in a lens. lens : `('a -> Identity<'b>) -> 'c -> Identity<'d>` The lens. f : `'a -> 'b` A function that converts the value we want to write in the part targeted by the lens. Returns: `'c -> 'd` The new object with the value modified.
`preview prism` Full Usage: `preview prism` Parameters: prism : `('a -> Const<First<'a>, 'b>) -> 'c -> Const<First<'d>, 'e>` - The prism. Returns: `'c -> 'd option` The value (if any) the prism is targeting.	Retrieve the first value targeted by a Prism, Fold or Traversal (or Some result from a Getter or Lens). See also (^?). prism : `('a -> Const<First<'a>, 'b>) -> 'c -> Const<First<'d>, 'e>` The prism. Returns: `'c -> 'd option` The value (if any) the prism is targeting.
`prism constructor getter f` Full Usage: `prism constructor getter f` Parameters: constructor : `'b -> 't` - The constructor function. getter : `'s -> Result<'a, 't>` - The getter function, having as first parameter the object and second the value to set. f : `'a -> ^F<'b>` - The free parameter. Returns: `'s -> ^F<'t>` The prism. Modifiers: inline Type parameters: 'b, 't, 's, 'a, ^F<'b>, ^F<'t>	Build a 'Prism' from a constructor and a getter. The prism should be assigned as an inline function of the free parameter, not a value, otherwise compiler will fail with a type constraint mismatch.Using Result instead of Option to permit the types of 's and 't to differ. constructor : `'b -> 't` The constructor function. getter : `'s -> Result<'a, 't>` The getter function, having as first parameter the object and second the value to set. f : `'a -> ^F<'b>` The free parameter. Returns: `'s -> ^F<'t>` The prism.
`prism' constructor getter f` Full Usage: `prism' constructor getter f` Parameters: constructor : `'b -> 's` - The constructor function. getter : `'s -> Option<'a>` - The getter function, having as first parameter the object and second the value to set. f : `'a -> ^F<'b>` - The free parameter. Returns: `'s -> ^F<'t>` The prism. Modifiers: inline Type parameters: 'b, 's, 'a, ^F<'b>, ^F<'t>	Build a 'Prism' from a constructor and a getter. The prism should be assigned as an inline function of the free parameter, not a value, otherwise compiler will fail with a type constraint mismatch.Using Option which makes 's and 't the same type. constructor : `'b -> 's` The constructor function. getter : `'s -> Option<'a>` The getter function, having as first parameter the object and second the value to set. f : `'a -> ^F<'b>` The free parameter. Returns: `'s -> ^F<'t>` The prism.
`setl lens v` Full Usage: `setl lens v` Parameters: lens : `('a -> Identity<'b>) -> 'c -> Identity<'d>` - The lens. v : `'b` - The value we want to write in the part targeted by the lens. Returns: `'c -> 'd` The new object with the value modified.	Write to a lens. lens : `('a -> Identity<'b>) -> 'c -> Identity<'d>` The lens. v : `'b` The value we want to write in the part targeted by the lens. Returns: `'c -> 'd` The new object with the value modified.
`to' k` Full Usage: `to' k` Parameters: k : `'a -> 'b` Returns: `^c -> ^d` Modifiers: inline	k : `'a -> 'b` Returns: `^c -> ^d`
`toListOf l` Full Usage: `toListOf l` Parameters: l : `('a -> Const<Endo<'a list>, 'b>) -> 'c -> Const<Endo<'d list>, 'e>` Returns: `'c -> 'd list`	Extract a list of the targets of a Fold. See also (^..). l : `('a -> Const<Endo<'a list>, 'b>) -> 'c -> Const<Endo<'d list>, 'e>` Returns: `'c -> 'd list`
`view lens` Full Usage: `view lens` Parameters: lens : `('a -> Const<'a, 'b>) -> 'c -> Const<'d, 'e>` - The lens. Returns: `'c -> 'd` The part the lens is targeting.	Read from a lens. lens : `('a -> Const<'a, 'b>) -> 'c -> Const<'d, 'e>` The lens. Returns: `'c -> 'd` The part the lens is targeting.
`withIso ai k` Full Usage: `withIso ai k` Parameters: ai : `Exchange<('a -> 'a), ('b -> Identity<'b>)> -> Exchange<'c, ('d -> Identity<'e>)>` k : `'c -> ('d -> 'e) -> 'f` Returns: `'f` Modifiers: inline	ai : `Exchange<('a -> 'a), ('b -> Identity<'b>)> -> Exchange<'c, ('d -> Identity<'e>)>` k : `'c -> ('d -> 'e) -> 'f` Returns: `'f`