[Caml-list] stdlib → Queue → iter : implementation question / (possibly) bikeshedding

["Matej Košík" <mail@matej-kosik.net>]

[-- Attachment #1.1: Type: text/plain, Size: 1403 bytes --]

Hi,

I just had a look at Queue.iter function as it is implemented by Ocaml standard library.

The original version

  (* https://github.com/ocaml/ocaml/blob/c08532f561548f6164278ba0d156da841aefe44a/stdlib/queue.ml#L100-L108 *)

  let iter =
    let rec iter f cell =
      match cell with
      | Nil -> ()
      | Cons { content; next } ->
        f content;
        iter f next
    in
  fun f q -> iter f q.first

I am wondering about two things.

--------------------------------------------------------------------------------

(1)

Why is the original implementation preferred over

  let iter f =
    let rec iter cell =
      match cell with
      | Nil -> ()
      | Cons { content; next } ->
        f content;
        iter next
    in
    fun q -> iter q.first

where "f" would be bound once and then reused as many times as necessary
(instead of passed over and over again within the inner "iter" loop).

--------------------------------------------------------------------------------

(2)

Why is the original implementation preferred over the following version

  let iter f q =
    let rec iter cell =
      match cell with
      | Nil -> ()
      | Cons { content; next } ->
        f content;
        iter next
    in
    iter q.first

?

Similar decisions where made elsewhere in stdlib so I am wondering what am I missing?


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 833 bytes --]