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|
(* TEST
toplevel;
*)
(* https://github.com/ocaml-multicore/ocaml-multicore/issues/479 *)
open Effect
open Effect.Deep
[@@@warning "-5-26"];;
Printexc.record_backtrace false;;
type ('a, 'container) iterator = ('a -> unit) -> 'container -> unit;;
type 'a generator = unit -> 'a option;;
type ('a,'container) iter2gen =
('a, 'container) iterator (* List.iter *)
-> 'container
-> 'a generator;;
type _ t += Hold: unit t
let iter2gen : _ iter2gen = fun iter c ->
let r = ref None in
let suspending_f x =
r:=Some x;
perform Hold
in
let next =
match_with (iter suspending_f) c
{ retc = (fun _ -> fun () -> None);
exnc = (fun e -> raise e);
effc = fun (type a) (e : a t) ->
match e with
| Hold -> Some (fun (k : (a,_) continuation) ->
fun () ->
let x = !r in
Printf.printf "Hold %s\n%!" (
match x with
| None -> "?"
| Some x->string_of_int x);
continue k ();
x)
| e -> None }
in
fun () -> next();;
let f () =
let gen = iter2gen List.iter in
let gen = gen [1;2;3] in
let gen() = match gen() with None->"?" | Some x-> string_of_int x in
Printf.printf "%s\n%!" (gen());
Printf.printf "%s\n%!" (gen());;
f ();;
|
