NAME

       Queue - First-in first-out queues.

Module

       Module   Queue

Documentation

       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  Queue.Empty  if  the
       queue is empty.

       val take_opt : 'a t -> 'a option

       take_opt q removes and returns the first element in queue q , or returns None if the queue
       is empty.

       Since 4.08

       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 Queue.Empty if the queue is empty.

       val peek_opt : 'a t -> 'a option

       peek_opt  q  returns the first element in queue q , without removing it from the queue, or
       returns None if the queue is empty.

       Since 4.08

       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.

   Iterators
       val to_seq : 'a t -> 'a Seq.t

       Iterate on the queue, in front-to-back order.  The behavior is not defined if the queue is
       modified during the iteration.

       Since 4.07

       val add_seq : 'a t -> 'a Seq.t -> unit

       Add the elements from a sequence to the end of the queue.

       Since 4.07

       val of_seq : 'a Seq.t -> 'a t

       Create a queue from a sequence.

       Since 4.07