package core_kernel

  1. Overview
  2. Docs
package core_kernel
Legend:
Library
Module
Module type
Parameter
Class
Class type

A simple polymorphic functional queue. Use this data structure for strictly first-in, first-out access to a sequence of values. For a similar data structure with enqueue and dequeue accessors on both ends of a sequence, see Core_kernel.Fdeque.

Amortized running times assume that enqueue/dequeue are used sequentially, threading the changing Fqueue through the calls.

type 'a t
include Bin_prot.Binable.S1 with type 'a t := 'a t
val bin_shape_t : Bin_prot.Shape.t -> Bin_prot.Shape.t
val bin_size_t : ('a, 'a t) Bin_prot.Size.sizer1
val bin_write_t : ('a, 'a t) Bin_prot.Write.writer1
val bin_read_t : ('a, 'a t) Bin_prot.Read.reader1
val __bin_read_t__ : ('a, int -> 'a t) Bin_prot.Read.reader1
val bin_writer_t : ('a, 'a t) Bin_prot.Type_class.S1.writer
val bin_reader_t : ('a, 'a t) Bin_prot.Type_class.S1.reader
val bin_t : ('a, 'a t) Bin_prot.Type_class.S1.t
val compare : ('a -> 'a -> Base.Int.t) -> 'a t -> 'a t -> Base.Int.t
val hash_fold_t : (Base.Hash.state -> 'a -> Base.Hash.state) -> Base.Hash.state -> 'a t -> Base.Hash.state
include Ppx_sexp_conv_lib.Sexpable.S1 with type 'a t := 'a t
val t_of_sexp : (Sexplib0.Sexp.t -> 'a) -> Sexplib0.Sexp.t -> 'a t
val sexp_of_t : ('a -> Sexplib0.Sexp.t) -> 'a t -> Sexplib0.Sexp.t
include Container.S1 with type 'a t := 'a t
val mem : 'a t -> 'a -> equal:('a -> 'a -> bool) -> bool

Checks whether the provided element is there, using equal.

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

fold t ~init ~f returns f (... f (f (f init e1) e2) e3 ...) en, where e1..en are the elements of t

val fold_result : 'a t -> init:'accum -> f:('accum -> 'a -> ('accum, 'e) Base.Result.t) -> ('accum, 'e) Base.Result.t

fold_result t ~init ~f is a short-circuiting version of fold that runs in the Result monad. If f returns an Error _, that value is returned without any additional invocations of f.

val fold_until : 'a t -> init:'accum -> f:('accum -> 'a -> ('accum, 'final) Base__.Container_intf.Continue_or_stop.t) -> finish:('accum -> 'final) -> 'final

fold_until t ~init ~f ~finish is a short-circuiting version of fold. If f returns Stop _ the computation ceases and results in that value. If f returns Continue _, the fold will proceed. If f never returns Stop _, the final result is computed by finish.

Example:

type maybe_negative =
  | Found_negative of int
  | All_nonnegative of { sum : int }

(** [first_neg_or_sum list] returns the first negative number in [list], if any,
    otherwise returns the sum of the list. *)
let first_neg_or_sum =
  List.fold_until ~init:0
    ~f:(fun sum x ->
      if x < 0
      then Stop (Found_negative x)
      else Continue (sum + x))
    ~finish:(fun sum -> All_nonnegative { sum })
;;

let x = first_neg_or_sum [1; 2; 3; 4; 5]
val x : maybe_negative = All_nonnegative {sum = 15}

let y = first_neg_or_sum [1; 2; -3; 4; 5]
val y : maybe_negative = Found_negative -3
val exists : 'a t -> f:('a -> bool) -> bool

Returns true if and only if there exists an element for which the provided function evaluates to true. This is a short-circuiting operation.

val for_all : 'a t -> f:('a -> bool) -> bool

Returns true if and only if the provided function evaluates to true for all elements. This is a short-circuiting operation.

val count : 'a t -> f:('a -> bool) -> int

Returns the number of elements for which the provided function evaluates to true.

val sum : (module Base__.Container_intf.Summable with type t = 'sum) -> 'a t -> f:('a -> 'sum) -> 'sum

Returns the sum of f i for all i in the container.

val find : 'a t -> f:('a -> bool) -> 'a option

Returns as an option the first element for which f evaluates to true.

val find_map : 'a t -> f:('a -> 'b option) -> 'b option

Returns the first evaluation of f that returns Some, and returns None if there is no such element.

val to_array : 'a t -> 'a array
val min_elt : 'a t -> compare:('a -> 'a -> int) -> 'a option

Returns a minimum (resp maximum) element from the collection using the provided compare function, or None if the collection is empty. In case of a tie, the first element encountered while traversing the collection is returned. The implementation uses fold so it has the same complexity as fold.

val max_elt : 'a t -> compare:('a -> 'a -> int) -> 'a option
include Base.Invariant.S1 with type 'a t := 'a t
val invariant : ('a -> unit) -> 'a t -> unit
include Base.Monad.S with type 'a t := 'a t
val (>>=) : 'a t -> ('a -> 'b t) -> 'b t

t >>= f returns a computation that sequences the computations represented by two monad elements. The resulting computation first does t to yield a value v, and then runs the computation returned by f v.

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

t >>| f is t >>= (fun a -> return (f a)).

module Monad_infix : sig ... end
val bind : 'a t -> f:('a -> 'b t) -> 'b t

bind t ~f = t >>= f

val return : 'a -> 'a t

return v returns the (trivial) computation that returns v.

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

map t ~f is t >>| f.

val join : 'a t t -> 'a t

join t is t >>= (fun t' -> t').

val ignore_m : 'a t -> unit t

ignore_m t is map t ~f:(fun _ -> ()). ignore_m used to be called ignore, but we decided that was a bad name, because it shadowed the widely used Caml.ignore. Some monads still do let ignore = ignore_m for historical reasons.

val all : 'a t list -> 'a list t
val all_unit : unit t list -> unit t

Like all, but ensures that every monadic value in the list produces a unit value, all of which are discarded rather than being collected into a list.

module Let_syntax : sig ... end

These are convenient to have in scope when programming with a monad:

val empty : 'a t

The empty queue.

val enqueue : 'a t -> 'a -> 'a t

enqueue t x returns a queue with adds x to the end of t. Complexity: O(1).

val enqueue_top : 'a t -> 'a -> 'a t

Enqueues a single element on the *top* of the queue. Complexity: amortized O(1) enqueue_top is deprecated, use Fdeque.t instead.

  • deprecated [since 2019-05] Use [Fdeque.t] instead.
val bot_exn : 'a t -> 'a

Returns the bottom (most recently enqueued) element. Raises Empty if no element is found. Complexity: O(1).

bot_exn is deprecated, use Fdeque.t instead.

  • deprecated [since 2019-05] Use [Fdeque.t] instead.
val bot : 'a t -> 'a Base.Option.t

Like bot_exn, but returns its result optionally, without exception. Complexity: O(1).

bot is deprecated, use Fdeque.t instead.

  • deprecated [since 2019-05] Use [Fdeque.t] instead.
val top_exn : 'a t -> 'a

Like bot_exn, except returns top (least recently enqueued) element. Complexity: O(1).

val top : 'a t -> 'a Base.Option.t

Like top_exn, but returns its result optionally, without exception, Complexity: O(1).

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

dequeue_exn t removes and returns the front of t, raising Empty if t is empty. Complexity: amortized O(1)

val dequeue : 'a t -> ('a * 'a t) Base.Option.t

Like dequeue_exn, but returns result optionally, without exception. Complexity: amortized O(1)

val discard_exn : 'a t -> 'a t

Returns version of queue with top element removed. Complexity: amortized O(1).

val to_list : 'a t -> 'a Base.List.t

to_list t returns a list of the elements in t in order from least-recently-added (at the head) to most-recently-added (at the tail). Complexity: O(n).

val of_list : 'a Base.List.t -> 'a t

of_list is the inverse of to_list. Complexity: O(n).

val to_sequence : 'a t -> 'a Sequence.t

to_sequence returns a Sequence.t of the elements in t in order from from least-recently-added (at the head) to most-recently-added (at the tail). Complexity (if the sequence is fully traversed): O(n).

to_list t = Sequence.to_list (to_sequence t)
val of_sequence : 'a Sequence.t -> 'a t

of_sequence is the inverse of to_sequence. Complexity (if the sequence is fully traversed): O(n).

val length : 'a t -> Base.Int.t

Complexity: O(1).

val is_empty : 'a t -> Base.Bool.t

Complexity: O(1).

val singleton : 'a -> 'a t
module Stable : sig ... end
OCaml

Innovation. Community. Security.

GitHub Discord Twitter Peertube RSS
About
Changelog Releases Industrial Users Academic Users Why OCaml
Ecosystem
Packages Community Events OCaml Planet Jobs
Resources
Install OCaml Get Started Platform Tools Language Manual Standard Library API Books Exercises Papers OCaml Playground Logo
Policies
Carbon Footprint Governance Privacy Code of Conduct