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|
(***********************************************************************)
(* 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 *)
(***********************************************************************)
(* $Id$ *)
(* This file to allow writing (3) for (S (S (S O)))
and still write (S y) for (S y) *)
open Pcoq
open Pp
open Util
open Names
open Coqast
open Ast
open Coqlib
open Termast
open Extend
exception Non_closed_number
let ast_O = ast_of_ref glob_O
let ast_S = ast_of_ref glob_S
(* For example, (nat_of_string "3") is <<(S (S (S O)))>> *)
let nat_of_int n dloc =
let ast_O = set_loc dloc ast_O in
let ast_S = set_loc dloc ast_S in
let rec mk_nat n =
if n <= 0 then
ast_O
else
Node(dloc,"APPLIST", [ast_S; mk_nat (n-1)])
in
mk_nat n
let pat_nat_of_int n dloc =
let ast_O = set_loc dloc ast_O in
let ast_S = set_loc dloc ast_S in
let rec mk_nat n =
if n <= 0 then
ast_O
else
Node(dloc,"PATTCONSTRUCT", [ast_S; mk_nat (n-1)])
in
mk_nat n
let nat_of_string s dloc =
nat_of_int (int_of_string s) dloc
let pat_nat_of_string s dloc =
pat_nat_of_int (int_of_string s) dloc
let rec int_of_nat_rec astS astO p =
match p with
| Node (_,"APPLIST", [b; a]) when alpha_eq(b,astS) ->
(int_of_nat_rec astS astO a)+1
| a when alpha_eq(a,astO) -> 1
(***** YES, 1, non 0 ... to print the successor of p *)
| _ -> raise Non_closed_number
let int_of_nat p =
try
Some (int_of_nat_rec ast_S ast_O p)
with
Non_closed_number -> None
let pr_S a = hov 0 (str "S" ++ brk (1,1) ++ a)
let rec pr_external_S std_pr = function
| Node (l,"APPLIST", [b; a]) when b = ast_S ->
str"(" ++ pr_S (pr_external_S std_pr a) ++ str")"
| p -> std_pr p
(* Declare the primitive printer *)
(* Prints not p, but the SUCCESSOR of p !!!!! *)
let nat_printer std_pr p =
match (int_of_nat p) with
| Some i -> str (string_of_int i)
| None -> pr_S (pr_external_S std_pr p)
let _ = Esyntax.Ppprim.add ("nat_printer", nat_printer)
(* Declare the primitive parser *)
let unat = create_univ_if_new "nat"
let number = create_constr_entry unat "number"
let pat_number = create_constr_entry unat "pat_number"
let _ =
Gram.extend number None
[None, None,
[[Gramext.Stoken ("INT", "")],
Gramext.action nat_of_string]]
let _ =
Gram.extend pat_number None
[None, None,
[[Gramext.Stoken ("INT", "")],
Gramext.action pat_nat_of_string]]
|
