package core
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doc/core/Core/Fdeque/index.html
Module Core.FdequeSource
A simple polymorphic functional double-ended queue. Use this if you need a queue-like data structure that provides enqueue and dequeue accessors on both ends. For strictly first-in, first-out access, see Fqueue.
Amortized running times assume that enqueue/dequeue are used sequentially, threading the changing deque through the calls.
include Ppx_hash_lib.Hashable.S1 with type 'a t := 'a t
val hash_fold_t :
(Base.Hash.state -> 'a -> Base.Hash.state) ->
Base.Hash.state ->
'a t ->
Base.Hash.stateContainer operations traverse deque elements front-to-back, like Front_to_back below. If you need faster traversal and don't care about the order, use Arbitrary_order below.
is_empty and length have worst-case complexity O(1).
include Container.S1 with type 'a t := 'a t
Checks whether the provided element is there, using equal.
fold t ~init ~f returns f (... f (f (f init e1) e2) e3 ...) en, where e1..en are the elements of t
val fold_result :
'a t ->
init:'acc ->
f:('acc -> 'a -> ('acc, 'e) Base.Result.t) ->
('acc, 'e) Base.Result.tfold_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.
val fold_until :
'a t ->
init:'acc ->
f:('acc -> 'a -> ('acc, 'final) Base.Container.Continue_or_stop.t) ->
finish:('acc -> 'final) ->
'finalfold_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 -3Returns true if and only if there exists an element for which the provided function evaluates to true. This is a short-circuiting operation.
Returns true if and only if the provided function evaluates to true for all elements. This is a short-circuiting operation.
Returns the number of elements for which the provided function evaluates to true.
Returns the sum of f i for all i in the container.
val sum :
(module Base.Container.Summable with type t = 'sum) ->
'a t ->
f:('a -> 'sum) ->
'sumReturns as an option the first element for which f evaluates to true.
Returns the first evaluation of f that returns Some, and returns None if there is no such element.
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.
include Base.Invariant.S1 with type 'a t := 'a t
include Base.Monad.S with type 'a t := 'a t
t >>= f returns a computation that sequences the computations represented by two monad elements. The resulting computation first does t to yield a value v, and then runs the computation returned by f v.
ignore_m t is map t ~f:(fun _ -> ()). ignore_m used to be called ignore, but we decided that was a bad name, because it shadowed the widely used Stdlib.ignore. Some monads still do let ignore = ignore_m for historical reasons.
Like all, but ensures that every monadic value in the list produces a unit value, all of which are discarded rather than being collected into a list.
These are convenient to have in scope when programming with a monad:
Traverse deque elements in arbitrary order.
Traverse deque elements front-to-back. Incurs up to O(n) additional time and space cost over Arbitrary_order.
Traverse deque elements back-to-front. Incurs up to O(n) additional time and space cost over Arbitrary_order.
of_list returns a deque with elements in the same front-to-back order as the list.
enqueue t side x produces t updated with x added to its side.
Complexity: worst-case O(1).
peek t side produces Some of the element at the side of t, or None if t is empty.
Complexity: worst-case O(1).
drop t side produces Some of t with the element at its side removed, or None if t is empty.
Complexity: amortized O(1), worst-case O(length t).
dequeue t side produces Option.both (peek t side) (drop t side).
Complexity: amortized O(1), worst-case O(length t).