(************************************************************************)
(*         *   The Coq Proof Assistant / The Coq Development Team       *)
(*  v      *   INRIA, CNRS and contributors - Copyright 1999-2018       *)
(* <O___,, *       (see CREDITS file for the list of authors)           *)
(*   \VV/  **************************************************************)
(*    //   *    This file is distributed under the terms of the         *)
(*         *     GNU Lesser General Public License Version 2.1          *)
(*         *     (see LICENSE file for the text of the license)         *)
(************************************************************************)

open Names
open Cbytecodes

(** Values *)

type values
type vm_env
type vm_global
type vprod
type vfun
type vfix
type vcofix
type vblock
type arguments
type vstack = values array
type to_update

val fun_val : vfun -> values
val fix_val : vfix -> values
val cofix_upd_val : to_update -> values

val fun_env : vfun -> vm_env
val fix_env : vfix -> vm_env
val cofix_env : vcofix -> vm_env
val cofix_upd_env : to_update -> vm_env

val vm_global : values array -> vm_global

(** Cast a value known to be a function, unsafe in general *)
val fun_of_val : values -> vfun

val crazy_val : values

(** Machine code *)

type tcode

type vswitch = {
    sw_type_code : tcode;
    sw_code : tcode;
    sw_annot : annot_switch;
    sw_stk : vstack;
    sw_env : vm_env
  }

external mkAccuCode : int -> tcode = "coq_makeaccu"

val fun_code : vfun -> tcode
val fix_code : vfix -> tcode
val cofix_upd_code : to_update -> tcode

type id_key =
| ConstKey of Constant.t
| VarKey of Id.t
| RelKey of Int.t
| EvarKey of Evar.t

val eq_id_key : id_key -> id_key -> bool

type atom =
  | Aid of id_key
  | Aind of inductive
  | Asort of Sorts.t

val get_atom_rel : unit -> atom array
(** Global table of rels *)

(** Zippers *)

type zipper =
  | Zapp of arguments
  | Zfix of vfix * arguments  (** might be empty *)
  | Zswitch of vswitch
  | Zproj of Constant.t (* name of the projection *)

type stack = zipper list

type whd =
  | Vprod of vprod
  | Vfun of vfun
  | Vfix of vfix * arguments option
  | Vcofix of vcofix * to_update * arguments option
  | Vconstr_const of int
  | Vconstr_block of vblock
  | Vatom_stk of atom * stack
  | Vuniv_level of Univ.Level.t

(** For debugging purposes only *)

val pr_atom : atom -> Pp.t
val pr_whd : whd -> Pp.t
val pr_stack : stack -> Pp.t

(** Constructors *)

val val_of_str_const : structured_constant -> values
val val_of_rel : int -> values
val val_of_named : Id.t -> values
val val_of_constant : Constant.t -> values
val val_of_evar : Evar.t -> values
val val_of_proj : Constant.t -> values -> values
val val_of_atom : atom -> values

external val_of_annot_switch : annot_switch -> values = "%identity"
external val_of_proj_name : Constant.t -> values = "%identity"

(** Destructors *)

val whd_val : values -> whd
val uni_lvl_val : values -> Univ.Level.t

(** Arguments *)

val nargs : arguments -> int
val arg : arguments -> int -> values

(** Product *)

val dom : vprod -> values
val codom : vprod -> vfun

(** Fun *)
external closure_arity : vfun -> int = "coq_closure_arity"

(** Fix *)

val current_fix : vfix -> int
val check_fix : vfix -> vfix -> bool
val rec_args : vfix -> int array
val first_fix : vfix -> vfix
val fix_types : vfix -> tcode array
val cofix_types : vcofix -> tcode array
external offset_closure_fix : vfix -> int -> vm_env = "coq_offset_closure"
val mk_fix_body : int -> int -> vfix -> vfun array

(** CoFix *)

val current_cofix : vcofix -> int
val check_cofix : vcofix -> vcofix -> bool
val mk_cofix_body : (vfun -> vstack -> values) -> int -> int -> vcofix -> values array

(** Block *)

val btag  : vblock -> int
val bsize : vblock -> int
val bfield : vblock -> int -> values

(** Switch *)

val check_switch : vswitch -> vswitch -> bool
val branch_arg : int -> Cbytecodes.tag * int -> values