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.
Also see Linked_queue, which has different performance characteristics.
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.
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
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.
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).
Sourceval filter_inplace : 'at->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.
Sourceval filteri_inplace : 'at->f:(int ->'a-> bool)-> 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.