List (loko.Loko.List)

val hd : ( 'F Stdlib.List.t, 'F, 'F, 'F Stdlib.List.t ) optic

A prism that focuses on the first removable element of a list.

let None = L.view_opt L.List.hd []
let 3 = L.view L.List.hd [3; 1; 4]
let [-3; 1; 4] = L.over L.List.hd (~-) [3; 1; 4]
let [1; 4] = L.remove L.List.hd [3; 1; 4]

val tl : 
  ( 'F Stdlib.List.t, 'F Stdlib.List.t, 'F Stdlib.List.t, 'F Stdlib.List.t )
    optic

A prism that focuses on the removable tail of a list.

let None = L.view_opt L.List.tl []
let [1; 4] = L.view L.List.tl [3; 1; 4]
let [3; 4; 1] = L.over L.List.tl List.rev [3; 1; 4]
let [3] = L.remove L.List.tl [3; 1; 4]

val map : 
  ( 'S, 'F, 'G, 'T ) optic ->
  ( 'S Stdlib.List.t, 'F Stdlib.List.t, 'G Stdlib.List.t, 'T Stdlib.List.t )
    optic

An isomorphism between lists.

val elems : ( 'F Stdlib.List.t, 'F, 'G, 'G Stdlib.List.t ) optic

A traversal over the removable elements of a list.

val to_array : ( 'F Stdlib.List.t, 'F array, 'G array, 'G Stdlib.List.t ) optic

Isomorphism between lists and arrays.

val to_option : 
  ( 'F Stdlib.List.t, 'F option, 'G option, 'G Stdlib.List.t ) optic

Isomorphism between singleton lists and options.

let None = L.view L.List.to_option ["more"; "than"; "one"]
let Some "exactly one" = L.view L.List.to_option ["exactly one"]
let None = L.view L.List.to_option []

val rev : 
  ( 'F Stdlib.List.t, 'F Stdlib.List.t, 'G Stdlib.List.t, 'G Stdlib.List.t )
    optic

An isomorphism whose focus is reverse of the list.

let [3; 1; 4] = L.over L.List.rev (List.cons 4) [3; 1]

val partition : 
  ( 'F -> bool ) ->
  ( 'F Stdlib.List.t,
    'F Stdlib.List.t * 'F Stdlib.List.t,
    'G Stdlib.List.t * 'G Stdlib.List.t,
    'G Stdlib.List.t )
    optic

An isomorphism that partitions a list into sublists of passes and fails.

let ([1; 2], [3; 4; 5]) =
  L.view (L.List.partition (fun x -> x <= 2)) [3; 1; 4; 2; 5]

val filter : 
  ( 'F -> bool ) ->
  ( 'F Stdlib.List.t, 'F Stdlib.List.t, 'F Stdlib.List.t, 'F Stdlib.List.t )
    optic

A lens that focuses on sublist of passes.

let [1; 2] = L.view (L.List.filter (fun x -> x <= 2)) [3; 1; 4; 2; 5]

val reject : 
  ( 'F -> bool ) ->
  ( 'F Stdlib.List.t, 'F Stdlib.List.t, 'F Stdlib.List.t, 'F Stdlib.List.t )
    optic

A lens that focuses on sublist of fails.

let [3; 4; 5] = L.view (L.List.reject (fun x -> x <= 2)) [3; 1; 4; 2; 5]