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Standard Library

Below is the API for the OCaml standard library. It's directly copied over from the OCaml Manual, formatted to the Reason syntax and styled accordingly. The API docs are work-in-progress; we'll be polishing these gradually!

If you're targeting JavaScript, the API docs for BuckleScript includes all of below, plus JS-specific APIs.

Module Queue

module Queue: sig .. end
First-in first-out queues.

This module implements queues (FIFOs), with in-place modification.

Warning This module is not thread-safe: each Queue.t value must be protected from concurrent access (e.g. with a Mutex.t). Failure to do so can lead to a crash.


type 'a t 
The type of queues containing elements of type 'a.
exception Empty
Raised when Queue.take or Queue.peek is applied to an empty queue.
val create : unit -> 'a t
Return a new queue, initially empty.
val add : 'a -> 'a t -> unit
add x q adds the element x at the end of the queue q.
val push : 'a -> 'a t -> unit
push is a synonym for add.
val take : 'a t -> 'a
take q removes and returns the first element in queue q, or raises Empty if the queue is empty.
val pop : 'a t -> 'a
pop is a synonym for take.
val peek : 'a t -> 'a
peek q returns the first element in queue q, without removing it from the queue, or raises Empty if the queue is empty.
val top : 'a t -> 'a
top is a synonym for peek.
val clear : 'a t -> unit
Discard all elements from a queue.
val copy : 'a t -> 'a t
Return a copy of the given queue.
val is_empty : 'a t -> bool
Return true if the given queue is empty, false otherwise.
val length : 'a t -> int
Return the number of elements in a queue.
val iter : ('a -> unit) -> 'a t -> unit
iter f q applies f in turn to all elements of q, from the least recently entered to the most recently entered. The queue itself is unchanged.
val fold : ('b -> 'a -> 'b) -> 'b -> 'a t -> 'b
fold f accu q is equivalent to List.fold_left f accu l, where l is the list of q's elements. The queue remains unchanged.
val transfer : 'a t -> 'a t -> unit
transfer q1 q2 adds all of q1's elements at the end of the queue q2, then clears q1. It is equivalent to the sequence iter (fun x -> add x q2) q1; clear q1, but runs in constant time.