Module type `Container_intf.S0_phantom`

type elt
type 'a t

val mem : _ t -> elt -> bool: Checks whether the provided element is there, using equality on elts.

val length : _ t -> int
val is_empty : _ t -> bool
val iter : _ t -> f:(elt -> unit) -> unit
val fold : _ t -> init:'accum -> f:('accum -> elt -> 'accum) -> 'accum: 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 : _ t -> init:'accum -> f:('accum -> elt -> ('accum, 'e) Base.Result.t) -> ('accum, 'e) Base.Result.t: 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.

val fold_until : _ t -> init:'accum -> f:('accum -> elt -> ('accum, 'final) Continue_or_stop.t) -> finish:('accum -> 'final) -> 'final

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

val exists : _ t -> f:(elt -> bool) -> bool: Returns true if and only if there exists an element for which the provided function evaluates to true. This is a short-circuiting operation.

val for_all : _ t -> f:(elt -> bool) -> bool: Returns true if and only if the provided function evaluates to true for all elements. This is a short-circuiting operation.

val count : _ t -> f:(elt -> bool) -> int: Returns the number of elements for which the provided function evaluates to true.

val sum : (module Summable with type t = 'sum) -> _ t -> f:(elt -> 'sum) -> 'sum: Returns the sum of f i for all i in the container. The order in which the elements will be summed is unspecified.

val find : _ t -> f:(elt -> bool) -> elt option: Returns as an option the first element for which f evaluates to true.

val find_map : _ t -> f:(elt -> 'a option) -> 'a option: Returns the first evaluation of f that returns Some, and returns None if there is no such element.

val to_list : _ t -> elt list
val to_array : _ t -> elt array
val min_elt : _ t -> compare:(elt -> elt -> int) -> elt option: Returns a min (resp max) 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.

val max_elt : _ t -> compare:(elt -> elt -> int) -> elt option