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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
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
exception Non_closed_number
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 nat_printer_0 _ _ = str "0"
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]]
(**********************************************************************)
(* Parsing *)
(* For example, (nat_of_string "3") is <<(S (S (S O)))>> *)
open Rawterm
open Libnames
open Bignat
open Symbols
let nat_of_int dloc = function
| POS n ->
if less_than (of_string "5000") n & Options.is_verbose () then begin
warning ("You may experiment stack overflow and segmentation fault\
\nwhile parsing numbers in nat greater than 5000");
flush_all ()
end;
let ref_O = RRef (dloc, glob_O) in
let ref_S = RRef (dloc, glob_S) in
let rec mk_nat n =
if is_nonzero n then
RApp (dloc,ref_S, [mk_nat (sub_1 n)])
else
ref_O
in
mk_nat n
| NEG n ->
user_err_loc (dloc, "nat_of_int",
str "Cannot interpret a negative number as a natural number")
let pat_nat_of_int dloc n name = match n with
| POS n ->
let rec mk_nat n name =
if is_nonzero n then
PatCstr (dloc,path_of_S,[mk_nat (sub_1 n) Anonymous],name)
else
PatCstr (dloc,path_of_O,[],name)
in
mk_nat n name
| NEG n ->
user_err_loc (dloc, "pat_nat_of_int",
str "Cannot interpret a negative number as a natural number")
let _ =
Symbols.declare_numeral_interpreter "nat_scope"
(nat_of_int,Some pat_nat_of_int)
(***********************************************************************)
(* Printing *)
exception Non_closed_number
let rec int_of_nat = function
| Node (_,"APPLIST", [b; a]) when alpha_eq(b,ast_S) -> (int_of_nat a) + 1
| a when alpha_eq(a,ast_O) -> 0
| _ -> raise Non_closed_number
(* Prints not p, but the SUCCESSOR of p !!!!! *)
let nat_printer_S p =
try
Some (int (int_of_nat p + 1))
with
Non_closed_number -> None
let nat_printer_O _ =
Some (int 0)
(* Declare the primitive printers *)
let _ =
Esyntax.declare_primitive_printer "nat_printer_S" "nat_scope" nat_printer_S
let _ =
Esyntax.declare_primitive_printer "nat_printer_O" "nat_scope" nat_printer_O
|