(* Step 4: the macOS shape. The game owns the main thread; the compiler and the
   listener run beside it.

   The question is NOT "can OCaml use threads" -- it is whether caml_startup can
   be called from a pthread that C spawned, while main() goes on to run a
   window loop it never returns from. That is the inversion item 11 settles on,
   and it is the one that has to be measured rather than assumed. *)

let compile file =
  let l = Flan.Load.program ~file (Flan.Parse.program (Flan.Reader.read_file file)) in
  let p = Flan.Check.program l.Flan.Load.decls in
  String.length (Flan.Emit.program ~dev:true p)

let () =
  Callback.register "spike_thread_compile" (fun (file : string) ->
      let tid = Thread.id (Thread.self ()) in
      match compile file with
      | n ->
        Printf.sprintf "compiled on OCaml thread %d: %d bytes of LLVM IR" tid n
      | exception e -> Printf.sprintf "FAILED: %s" (Printexc.to_string e));
  Callback.register "spike_domains" (fun () ->
      (* A second domain doing real work while the main thread is elsewhere --
         5.2's multicore runtime, which is the objection item 12 says has gone
         away. Confirmed rather than assumed. *)
      let d = Domain.spawn (fun () ->
          let s = ref 0 in
          for i = 1 to 5_000_000 do s := !s + i done;
          (Domain.self () :> int), !s)
      in
      let id, s = Domain.join d in
      Printf.sprintf "domain %d summed to %d; recommended_domain_count = %d"
        id s (Domain.recommended_domain_count ()))