(***********************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team    *)
(* <O___,, *        INRIA-Rocquencourt  &  LRI-CNRS-Orsay              *)
(*   \VV/  *************************************************************)
(*    //   *      This file is distributed under the terms of the      *)
(*         *       GNU Lesser General Public License Version 2.1       *)
(***********************************************************************)

(* $Id$ *)

open Util
open Names
open Term
open Instantiate
open Sign
open Environ
open Safe_typing
open Summary

(* We introduce here the global environment of the system, and we declare it
   as a synchronized table. *)

let global_env = ref empty_environment

let safe_env () = !global_env

let env () = env_of_safe_env !global_env

let _ = 
  declare_summary "Global environment"
    { freeze_function = (fun () -> !global_env);
      unfreeze_function = (fun fr -> global_env := fr);
      init_function = (fun () -> global_env := empty_environment);
      survive_section = false }

(* Then we export the functions of [Typing] on that environment. *)

let universes () = universes !global_env
let context () = context !global_env
let named_context () = named_context !global_env

let push_named_def idc =
  let d, env = check_and_push_named_def idc !global_env in
  global_env := env; d

let push_named_assum idc =
  let d, env = check_and_push_named_assum idc !global_env in
  global_env := env; d

let add_parameter sp c l = global_env := add_parameter sp c l !global_env
let add_constant sp ce l = global_env := add_constant sp ce l !global_env
let add_discharged_constant sp r l = 
  global_env := add_discharged_constant sp r l !global_env
let add_mind sp mie l = global_env := add_mind sp mie l !global_env
let add_constraints c = global_env := add_constraints c !global_env

let pop_named_decls ids = global_env := pop_named_decls ids !global_env

let lookup_named id = lookup_named id !global_env
let lookup_constant sp = lookup_constant sp !global_env
let lookup_mind sp = lookup_mind sp !global_env
let lookup_mind_specif c = lookup_mind_specif c !global_env

let export s = export !global_env s
let import cenv = global_env := import cenv !global_env

(* Some instanciations of functions from [Environ]. *)

let sp_of_global ref = Environ.sp_of_global (env_of_safe_env !global_env) ref

(* To know how qualified a name should be to be understood in the current env*)

let qualid_of_global ref =  
  let sp = sp_of_global ref in
  let id = basename sp in
  let rec find_visible dir qdir =
    let qid = Nametab.make_qualid qdir id in
    if (try Nametab.locate qid = ref with Not_found -> false) then qid
    else match dir with
      | [] -> Nametab.qualid_of_sp sp
      | a::l -> find_visible l (a::qdir)
  in
  find_visible (List.rev (dirpath sp)) []

let string_of_global ref = Nametab.string_of_qualid (qualid_of_global ref)

(*s Function to get an environment from the constants part of the global
    environment and a given context. *)

let env_of_context hyps = 
  change_hyps (fun _ -> hyps) (env_of_safe_env !global_env)

(* Functions of [Inductive], composed with [lookup_mind_specif]. *)
(* Rem:Cannot open Inductive to avoid clash with Inductive.lookup_mind_specif*)

let mind_is_recursive =
  Util.compose Inductive.mis_is_recursive lookup_mind_specif 

let mind_nconstr = Util.compose Inductive.mis_nconstr lookup_mind_specif
let mind_nparams = Util.compose Inductive.mis_nparams lookup_mind_specif
let mind_nf_lc = Util.compose Inductive.mis_nf_lc lookup_mind_specif