(************************************************************************)
(*         *   The Coq Proof Assistant / The Coq Development Team       *)
(*  v      *         Copyright INRIA, CNRS and contributors             *)
(* <O___,, * (see version control and CREDITS file for authors & dates) *)
(*   \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 Libnames

open Pcoq.Prim

let local_make_qualid loc l id = make_qualid ~loc (DirPath.make l) id

let my_int_of_string ?loc s =
  try
    int_of_string s
  with Failure _ ->
    CErrors.user_err ?loc (Pp.str "This number is too large.")

let my_to_nat_string ?loc s =
  match NumTok.Unsigned.to_nat s with
  | Some n -> n
  | None ->
    CErrors.user_err ?loc Pp.(str "This number is not an integer.")

let test_pipe_closedcurly =
  let open Pcoq.Lookahead in
  to_entry "test_pipe_closedcurly" begin
    lk_kw "|" >> lk_kw "}" >> check_no_space
  end

let test_minus_nat =
  let open Pcoq.Lookahead in
  to_entry "test_minus_nat" begin
    lk_kw "-" >> lk_nat >> check_no_space
  end

}

GRAMMAR EXTEND Gram
  GLOBAL:
    bignat bigint natural integer identref name ident hyp preident
    fullyqualid qualid reference dirpath ne_lstring
    ne_string string lstring pattern_ident by_notation
    smart_global bar_cbrace strategy_level;
  preident:
    [ [ s = IDENT -> { s } ] ]
  ;
  ident:
    [ [ s = IDENT -> { Id.of_string s } ] ]
  ;
  pattern_ident:
    [ [ LEFTQMARK; id = ident -> { CAst.make ~loc id } ] ]
  ;
  identref:
    [ [ id = ident -> { CAst.make ~loc id } ] ]
  ;
  hyp: (* as identref, but interpreted as an hypothesis in tactic notations *)
    [ [ id = identref -> { id } ] ]
  ;
  field:
    [ [ s = FIELD -> { Id.of_string s } ] ]
  ;
  fields:
    [ [ id = field; f = fields -> { let (l,id') = f in (l@[id],id') }
      | id = field -> { ([],id) }
      ] ]
  ;
  fullyqualid:
    [ [ id = ident; f=fields -> { let (l,id') = f in CAst.make ~loc @@ id::List.rev (id'::l) }
      | id = ident -> { CAst.make ~loc [id] }
      ] ]
  ;
  name:
    [ [ IDENT "_"  -> { CAst.make ~loc Anonymous }
      | id = ident -> { CAst.make ~loc @@ Name id } ] ]
  ;
  reference:
    [ [ id = ident; f = fields -> {
        let (l,id') = f in
        local_make_qualid loc (l@[id]) id' }
      | id = ident -> { qualid_of_ident ~loc id }
      ] ]
  ;
  qualid: (* Synonymous to reference *)
    [ [ qid = reference -> { qid } ] ]
  ;
  by_notation:
    [ [ s = ne_string; sc = OPT ["%"; key = IDENT -> { key } ] -> { (s, sc) } ] ]
  ;
  smart_global:
    [ [ c = reference -> { CAst.make ~loc @@ Constrexpr.AN c }
      | ntn = by_notation -> { CAst.make ~loc @@ Constrexpr.ByNotation ntn } ] ]
  ;
  ne_string:
    [ [ s = STRING ->
        { if s="" then CErrors.user_err ~loc (Pp.str"Empty string."); s }
    ] ]
  ;
  ne_lstring:
    [ [ s = ne_string -> { CAst.make ~loc s } ] ]
  ;
  dirpath:
    [ [ id = ident; l = LIST0 field ->
        { DirPath.make (List.rev (id::l)) } ] ]
  ;
  string:
    [ [ s = STRING -> { s } ] ]
  ;
  lstring:
    [ [ s = string -> { CAst.make ~loc s } ] ]
  ;
  integer:
    [ [ i = bigint -> { my_int_of_string ~loc i } ] ]
  ;
  natural:
    [ [ i = bignat -> { my_int_of_string ~loc i } ] ]
  ;
  bigint:
    [ [ i = bignat -> { i }
      | test_minus_nat; "-"; i = bignat -> { "-" ^ i } ] ]
  ;
  bignat:
    [ [ i = NUMBER -> { my_to_nat_string ~loc i } ] ]
  ;
  bar_cbrace:
    [ [ test_pipe_closedcurly; "|"; "}" -> { () } ] ]
  ;
  strategy_level:
    [ [ IDENT "expand" -> { Conv_oracle.Expand }
      | IDENT "opaque" -> { Conv_oracle.Opaque }
      | n=integer -> { Conv_oracle.Level n }
      | IDENT "transparent" -> { Conv_oracle.transparent } ] ]
  ;
END