(************************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2014     *)
(*   \VV/  **************************************************************)
(*    //   *      This file is distributed under the terms of the       *)
(*         *       GNU Lesser General Public License Version 2.1        *)
(************************************************************************)

(* Created by Jacek Chrzaszcz, Aug 2002 as part of the implementation of
   the Coq module system *)

(* This module provides the main entry points for type-checking basic
   declarations *)

open Util
open Names
open Univ
open Term
open Reduction
open Sign
open Declarations
open Inductive
open Environ
open Entries
open Type_errors
open Indtypes
open Typeops

let constrain_type env j cst1 = function
  | None ->
      make_polymorphic_if_constant_for_ind env j, cst1
  | Some t ->
      let (tj,cst2) = infer_type env t in
      let (_,cst3) = judge_of_cast env j DEFAULTcast tj in
	assert (eq_constr t tj.utj_val);
	let cstrs = union_constraints (union_constraints cst1 cst2) cst3 in
	  NonPolymorphicType t, cstrs

let local_constrain_type env j cst1 = function
  | None ->
      j.uj_type, cst1
  | Some t ->
      let (tj,cst2) = infer_type env t in
      let (_,cst3) = judge_of_cast env j DEFAULTcast tj in
      assert (eq_constr t tj.utj_val);
      t, union_constraints (union_constraints cst1 cst2) cst3

let translate_local_def env (b,topt) =
  let (j,cst) = infer env b in
  let (typ,cst) = local_constrain_type env j cst topt in
    (j.uj_val,typ,cst)

let translate_local_assum env t =
  let (j,cst) = infer env t in
  let t = Typeops.assumption_of_judgment env j in
    (t,cst)

(*

(* Same as push_named, but check that the variable is not already
   there. Should *not* be done in Environ because tactics add temporary
   hypothesis many many times, and the check performed here would
   cost too much. *)
let safe_push_named (id,_,_ as d) env =
  let _ =
    try
      let _ = lookup_named id env in
      error ("Identifier "^string_of_id id^" already defined.")
    with Not_found -> () in
  push_named d env

let push_named_def = push_rel_or_named_def safe_push_named
let push_rel_def = push_rel_or_named_def push_rel

let push_rel_or_named_assum push (id,t) env =
  let (j,cst) = safe_infer env t in
  let t = Typeops.assumption_of_judgment env j in
  let env' = add_constraints cst env in
  let env'' = push (id,None,t) env' in
  (cst,env'')

let push_named_assum = push_rel_or_named_assum push_named
let push_rel_assum d env = snd (push_rel_or_named_assum push_rel d env)

let push_rels_with_univ vars env =
  List.fold_left (fun env nvar -> push_rel_assum nvar env) env vars
*)


(* Insertion of constants and parameters in environment. *)

let infer_declaration env dcl =
  match dcl with
  | DefinitionEntry c ->
      let (j,cst) = infer env c.const_entry_body in
      let j =
        {uj_val = hcons_constr j.uj_val;
         uj_type = hcons_constr j.uj_type} in
      let (typ,cst) = constrain_type env j cst c.const_entry_type in
      let def =
	if c.const_entry_opaque
	then OpaqueDef (Declarations.opaque_from_val j.uj_val)
	else Def (Declarations.from_val j.uj_val)
      in
      def, typ, cst, c.const_entry_secctx
  | ParameterEntry (ctx,t,nl) ->
      let (j,cst) = infer env t in
      let t = hcons_constr (Typeops.assumption_of_judgment env j) in
      Undef nl, NonPolymorphicType t, cst, ctx

let global_vars_set_constant_type env = function
  | NonPolymorphicType t -> global_vars_set env t
  | PolymorphicArity (ctx,_) ->
      Sign.fold_rel_context
        (fold_rel_declaration
	  (fun t c -> Idset.union (global_vars_set env t) c))
      ctx ~init:Idset.empty

let build_constant_declaration env kn (def,typ,cst,ctx) =
  let hyps = 
    let inferred =
      let ids_typ = global_vars_set_constant_type env typ in
      let ids_def = match def with
      | Undef _ -> Idset.empty
      | Def cs -> global_vars_set env (Declarations.force cs)
      | OpaqueDef lc -> 
          global_vars_set env (Declarations.force_opaque lc) in
      keep_hyps env (Idset.union ids_typ ids_def) in
    let declared = match ctx with
      | None -> inferred 
      | Some declared -> declared in
    let mk_set l = List.fold_right Idset.add (List.map pi1 l) Idset.empty in
    let inferred_set, declared_set = mk_set inferred, mk_set declared in
    if not (Idset.subset inferred_set declared_set) then
      error ("The following section variable are used but not declared:\n"^
        (String.concat ", " (List.map string_of_id
          (Idset.elements (Idset.diff inferred_set declared_set)))));
    declared in
  let tps = Cemitcodes.from_val (compile_constant_body env def) in
  { const_hyps = hyps;
    const_body = def;
    const_type = typ;
    const_body_code = tps;
    const_constraints = cst }

(*s Global and local constant declaration. *)

let translate_constant env kn ce =
  build_constant_declaration env kn (infer_declaration env ce)

let translate_recipe env kn r =
  build_constant_declaration env kn 
    (let def,typ,cst,hyps = Cooking.cook_constant env r in
     def,typ,cst,Some hyps)

(* Insertion of inductive types. *)

let translate_mind env kn mie = check_inductive env kn mie