Module Core_queue

A queue implemented with an array.

The implementation will grow the array as necessary. The array will never automatically be shrunk, but the size can be interrogated and set with capacity and set_capacity.

Iteration functions (iter, fold, map, concat_map, filter, filter_map, filter_inplace, and some functions from Container.S1) will raise if the queue is modified during iteration.

Differences from the standard module: enqueue replaces push and add, and takes the queue first. dequeue replaces pop and take, and returns an option rather than raising Empty. dequeue_exn is available if you want to raise Empty. iter and fold take labeled arguments. blit_transfer replaces transfer but is markedly different; see below.


type 'a t
val t_of_sexp : (Sexplib.Sexp.t -> 'a) -> Sexplib.Sexp.t -> 'a t
val sexp_of_t : ('a -> Sexplib.Sexp.t) -> 'a t -> Sexplib.Sexp.t
val compare : ('a -> 'a -> int) -> 'a t -> 'a t -> int
val bin_read_t : 'a Bin_prot.Read.reader -> 'a t Bin_prot.Read.reader
val __bin_read_t__ : 'a Bin_prot.Read.reader -> (int -> 'a t) Bin_prot.Read.reader
val bin_size_t : 'a Bin_prot.Size.sizer -> 'a t Bin_prot.Size.sizer
val bin_write_t : 'a Bin_prot.Write.writer -> 'a t Bin_prot.Write.writer
include Binary_searchable.S1 with type 'a t := 'a t
type 'a t
val binary_search : ('a t, 'a) Binary_searchable_intf.binary_search
val binary_search_segmented : ('a t, 'a) Binary_searchable_intf.binary_search_segmented
include Container.S1 with type 'a t := 'a t
type 'a t
val mem : ?equal:('a -> 'a -> bool) -> 'a t -> 'a -> bool

Checks whether the provided element is there, using polymorphic compare if equal is not provided

val length : 'a t -> int
val is_empty : 'a t -> bool
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 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 Commutative_group.S with type t = 'sum) -> 'a t -> f:('a -> 'sum) -> 'sum

Returns the sum of f i for 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_list : 'a t -> 'a list
val to_array : 'a t -> 'a array
val min_elt : 'a t -> cmp:('a -> 'a -> int) -> 'a option

Returns a minimum (resp maximum) element from the collection using the provided cmp 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 -> cmp:('a -> 'a -> int) -> 'a option
include Equal.S1 with type 'a t := 'a t
type 'a t
val equal : 'a Equal.equal -> 'a t Equal.equal
include Invariant.S1 with type 'a t := 'a t
type 'a t
val invariant : 'a Invariant_intf.inv -> 'a t Invariant_intf.inv
val create : ?capacity:int -> unit -> _ t

Create an empty queue.

val singleton : 'a -> 'a t

Create a queue with one element.

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

enqueue t a adds a to the end of t.

val enqueue_all : 'a t -> 'a list -> unit

enqueue_all t list adds all elements in list to t in order of list.

val dequeue : 'a t -> 'a option

dequeue t removes and returns the front element of t, if any.

val dequeue_exn : 'a t -> 'a
val peek : 'a t -> 'a option

peek t returns but does not remove the front element of t, if any.

val peek_exn : 'a t -> 'a
val last : 'a t -> 'a option

last t returns the most recently enqueued element in t, if any.

val last_exn : 'a t -> 'a
val clear : _ t -> unit
val copy : 'a t -> 'a t
val blit_transfer : src:'a t -> dst:'a t -> ?len:int -> unit -> unit

Transfers up to len elements from the front of src to the end of dst, removing them from src. It is an error if len < 0.

Aside from a call to set_capacity dst if needed, runs in O(len) time

val of_list : 'a list -> 'a t

of_list list returns a queue t with the elements of list in the same order as the elements of list (i.e. the first element of t is the first element of the list).

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

creates a new queue with elements equal to List.concat_map ~f (to_list t).

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

filter_map creates a new queue with elements equal to List.filter_map ~f (to_list t).

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

filter is like filter_map, except with List.filter.

val filter_inplace : 'a t -> f:('a -> bool) -> unit

filter_inplace t ~f removes all elements of t that don't satisfy f. If f raises, t is unchanged. This is inplace in that it modifies t; however, it uses space linear in the final length of t.

val of_array : 'a array -> 'a t
val get : 'a t -> int -> 'a

get t i returns the i'th element in t, where the 0'th element is at the front of t and the length t - 1 element is at the back.

val set : 'a t -> int -> 'a -> unit
val capacity : _ t -> int

Returns the current length of the backing array.

val set_capacity : _ t -> int -> unit

set_capacity t c sets the capacity of t's backing array to at least max c (length t). If t's capacity changes, then this involves allocating a new backing array and copying the queue elements over. set_capacity may decrease the capacity of t, if c < capacity t.