.TH "Stdlib.Queue" 3o 2023-09-18 OCamldoc "OCaml library"
.SH NAME
Stdlib.Queue \- no description
.SH Module
Module   Stdlib.Queue
.SH Documentation
.sp
Module
.BI "Queue"
 : 
.B (module Stdlib__Queue)

.sp

.sp

.sp
.sp
.I type 
.B 'a
.I t 

.sp
The type of queues containing elements of type 
.ft B
\&'a
.ft R
\&.

.sp

.I exception Empty 

.sp
Raised when 
.ft B
Queue\&.take
.ft R
or 
.ft B
Queue\&.peek
.ft R
is applied to an empty queue\&.

.sp

.I val create 
: 
.B unit -> 'a t
.sp
Return a new queue, initially empty\&.

.sp

.I val add 
: 
.B 'a -> 'a t -> unit
.sp

.ft B
add x q
.ft R
adds the element 
.ft B
x
.ft R
at the end of the queue 
.ft B
q
.ft R
\&.

.sp

.I val push 
: 
.B 'a -> 'a t -> unit
.sp

.ft B
push
.ft R
is a synonym for 
.ft B
add
.ft R
\&.

.sp

.I val take 
: 
.B 'a t -> 'a
.sp

.ft B
take q
.ft R
removes and returns the first element in queue 
.ft B
q
.ft R
,
or raises 
.ft B
Queue\&.Empty
.ft R
if the queue is empty\&.

.sp

.I val take_opt 
: 
.B 'a t -> 'a option
.sp

.ft B
take_opt q
.ft R
removes and returns the first element in queue 
.ft B
q
.ft R
,
or returns 
.ft B
None
.ft R
if the queue is empty\&.

.sp
.B "Since"
4.08

.sp

.I val pop 
: 
.B 'a t -> 'a
.sp

.ft B
pop
.ft R
is a synonym for 
.ft B
take
.ft R
\&.

.sp

.I val peek 
: 
.B 'a t -> 'a
.sp

.ft B
peek q
.ft R
returns the first element in queue 
.ft B
q
.ft R
, without removing
it from the queue, or raises 
.ft B
Queue\&.Empty
.ft R
if the queue is empty\&.

.sp

.I val peek_opt 
: 
.B 'a t -> 'a option
.sp

.ft B
peek_opt q
.ft R
returns the first element in queue 
.ft B
q
.ft R
, without removing
it from the queue, or returns 
.ft B
None
.ft R
if the queue is empty\&.

.sp
.B "Since"
4.08

.sp

.I val top 
: 
.B 'a t -> 'a
.sp

.ft B
top
.ft R
is a synonym for 
.ft B
peek
.ft R
\&.

.sp

.I val clear 
: 
.B 'a t -> unit
.sp
Discard all elements from a queue\&.

.sp

.I val copy 
: 
.B 'a t -> 'a t
.sp
Return a copy of the given queue\&.

.sp

.I val is_empty 
: 
.B 'a t -> bool
.sp
Return 
.ft B
true
.ft R
if the given queue is empty, 
.ft B
false
.ft R
otherwise\&.

.sp

.I val length 
: 
.B 'a t -> int
.sp
Return the number of elements in a queue\&.

.sp

.I val iter 
: 
.B ('a -> unit) -> 'a t -> unit
.sp

.ft B
iter f q
.ft R
applies 
.ft B
f
.ft R
in turn to all elements of 
.ft B
q
.ft R
,
from the least recently entered to the most recently entered\&.
The queue itself is unchanged\&.

.sp

.I val fold 
: 
.B ('b -> 'a -> 'b) -> 'b -> 'a t -> 'b
.sp

.ft B
fold f accu q
.ft R
is equivalent to 
.ft B
List\&.fold_left f accu l
.ft R
,
where 
.ft B
l
.ft R
is the list of 
.ft B
q
.ft R
\&'s elements\&. The queue remains
unchanged\&.

.sp

.I val transfer 
: 
.B 'a t -> 'a t -> unit
.sp

.ft B
transfer q1 q2
.ft R
adds all of 
.ft B
q1
.ft R
\&'s elements at the end of
the queue 
.ft B
q2
.ft R
, then clears 
.ft B
q1
.ft R
\&. It is equivalent to the
sequence 
.ft B
iter (fun x \-> add x q2) q1; clear q1
.ft R
, but runs
in constant time\&.

.sp

.PP
.SS Iterators

.PP

.I val to_seq 
: 
.B 'a t -> 'a Seq.t
.sp
Iterate on the queue, in front\-to\-back order\&.
The behavior is not specified if the queue is modified
during the iteration\&.

.sp
.B "Since"
4.07

.sp

.I val add_seq 
: 
.B 'a t -> 'a Seq.t -> unit
.sp
Add the elements from a sequence to the end of the queue\&.

.sp
.B "Since"
4.07

.sp

.I val of_seq 
: 
.B 'a Seq.t -> 'a t
.sp
Create a queue from a sequence\&.

.sp
.B "Since"
4.07

.sp