package containers

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package containers
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Random-Access Lists

This is an OCaml implementation of Okasaki's paper "Purely Functional Random Access Lists". It defines a list-like data structure with O(1) cons/tail operations, and O(log(n)) lookup/modification operations.

This module used to be part of containers.misc

status: stable

  • since 0.13
type +'a t

List containing elements of type 'a

val empty : 'a t

Empty list

val is_empty : _ t -> bool

Check whether the list is empty

val cons : 'a -> 'a t -> 'a t

Add an element at the front of the list

val return : 'a -> 'a t

Singleton

val map : f:('a -> 'b) -> 'a t -> 'b t

Map on elements

val mapi : f:(int -> 'a -> 'b) -> 'a t -> 'b t

Map with index

val hd : 'a t -> 'a

First element of the list, or

  • raises Invalid_argument

    if the list is empty

val tl : 'a t -> 'a t

Remove the first element from the list, or

  • raises Invalid_argument

    if the list is empty

val front : 'a t -> ('a * 'a t) option

Remove and return the first element of the list

val front_exn : 'a t -> 'a * 'a t

Unsafe version of front.

  • raises Invalid_argument

    if the list is empty

val length : 'a t -> int

Number of elements. Complexity O(ln n) where n=number of elements

val get : 'a t -> int -> 'a option

get l i accesses the i-th element of the list. O(log(n)).

val get_exn : 'a t -> int -> 'a

Unsafe version of get

  • raises Invalid_argument

    if the list has less than i+1 elements.

val set : 'a t -> int -> 'a -> 'a t

set l i v sets the i-th element of the list to v. O(log(n)).

  • raises Invalid_argument

    if the list has less than i+1 elements.

val remove : 'a t -> int -> 'a t

remove l i removes the i-th element of v.

  • raises Invalid_argument

    if the list has less than i+1 elements.

val append : 'a t -> 'a t -> 'a t
val filter : f:('a -> bool) -> 'a t -> 'a t
val filter_map : f:('a -> 'b option) -> 'a t -> 'b t
val flat_map : ('a -> 'b t) -> 'a t -> 'b t
val flatten : 'a t t -> 'a t
val app : ('a -> 'b) t -> 'a t -> 'b t
val take : int -> 'a t -> 'a t
val take_while : f:('a -> bool) -> 'a t -> 'a t
val drop : int -> 'a t -> 'a t
val drop_while : f:('a -> bool) -> 'a t -> 'a t
val take_drop : int -> 'a t -> 'a t * 'a t

take_drop n l splits l into a, b such that length a = n if length l >= n, and such that append a b = l

val iter : f:('a -> unit) -> 'a t -> unit

Iterate on the list's elements

val iteri : f:(int -> 'a -> unit) -> 'a t -> unit
val fold : f:('b -> 'a -> 'b) -> x:'b -> 'a t -> 'b

Fold on the list's elements

val fold_rev : f:('b -> 'a -> 'b) -> x:'b -> 'a t -> 'b

Fold on the list's elements, in reverse order (starting from the tail)

val rev_map : f:('a -> 'b) -> 'a t -> 'b t

rev_map f l is the same as map f (rev l)

val rev : 'a t -> 'a t

Reverse the list

val equal : ?eq:('a -> 'a -> bool) -> 'a t -> 'a t -> bool
val compare : ?cmp:('a -> 'a -> int) -> 'a t -> 'a t -> int

Lexicographic comparison

Utils

val make : int -> 'a -> 'a t
val repeat : int -> 'a t -> 'a t

repeat n l is append l (append l ... l) n times

val range : int -> int -> int t

range i j is i; i+1; ... ; j or j; j-1; ...; i

Conversions

type 'a sequence = ('a -> unit) -> unit
type 'a gen = unit -> 'a option
val add_list : 'a t -> 'a list -> 'a t
val of_list : 'a list -> 'a t

Convert a list to a RAL. Caution: non tail-rec

val to_list : 'a t -> 'a list
val of_list_map : f:('a -> 'b) -> 'a list -> 'b t

Combination of of_list and map

val of_array : 'a array -> 'a t
val add_array : 'a t -> 'a array -> 'a t
val to_array : 'a t -> 'a array

More efficient than on usual lists

val add_seq : 'a t -> 'a sequence -> 'a t
val of_seq : 'a sequence -> 'a t
val to_seq : 'a t -> 'a sequence
val add_gen : 'a t -> 'a gen -> 'a t
val of_gen : 'a gen -> 'a t
val to_gen : 'a t -> 'a gen

Infix

module Infix : sig ... end
include module type of Infix
val (@+) : 'a -> 'a t -> 'a t

Cons (alias to cons)

val (>>=) : 'a t -> ('a -> 'b t) -> 'b t

Alias to flat_map

val (>|=) : 'a t -> ('a -> 'b) -> 'b t

Alias to map

val (<*>) : ('a -> 'b) t -> 'a t -> 'b t

Alias to app

val (--) : int -> int -> int t

Alias to range

val (--^) : int -> int -> int t

a -- b is the integer range from a to b, where b is excluded.

  • since 0.17

IO

type 'a printer = Format.formatter -> 'a -> unit
val print : ?sep:string -> 'a printer -> 'a t printer