(* Check what opcode is in the formula at slot 3 *)

open Nock_lib

let () =
  Eio_main.run (fun env ->
    let fs = Eio.Stdenv.fs env in
    let pill_bytes = Eio.Path.(load (fs / "ivory.pill")) |> Bytes.of_string in
    let pill = Serial.cue pill_bytes in
    let core = Noun.tail pill in

    (* Get the formula at slot 3 *)
    let formula = Noun.slot (Z.of_int 3) core in
    Printf.printf "Formula (slot 3) mug: 0x%08lx\n" (Noun.mug formula);
    Printf.printf "Formula is: %s\n" (if Noun.is_cell formula then "cell" else "atom");

    if Noun.is_cell formula then begin
      let h = Noun.head formula in
      Printf.printf "Formula head is: %s\n" (if Noun.is_cell h then "cell" else "atom");
      match h with
      | Noun.Atom { z; _ } when Z.fits_int z ->
          Printf.printf "Formula starts with opcode: %d\n" (Z.to_int z)
      | Noun.Cell _ ->
          Printf.printf "Formula starts with CELL (distribution)\n"
      | _ ->
          Printf.printf "Formula head is large atom\n"
    end
  )