From 7f2c52bcf588abfcbf30530bae240244229304a4 Mon Sep 17 00:00:00 2001
From: letouzey
Date: Fri, 27 Mar 2009 17:53:43 +0000
Subject: Parsing files for numerals (+ ascii/string) moved into plugins

 Idea: make coqtop more independant of the standard library.
 In the future, we can imagine loading the syntax for numerals right
 after their definition. For the moment, it is easier to stay lazy
 and load the syntax plugins slightly before the definitions.

 After this commit, the main (sole ?) references to theories/
 from the core ml files are in Coqlib (but many parts of coqlib
 are only used by plugins), and it mainly concerns Init
 (+ Logic/JMeq and maybe a few others).

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@12024 85f007b7-540e-0410-9357-904b9bb8a0f7
---
 plugins/syntax/r_syntax.ml | 125 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 125 insertions(+)
 create mode 100644 plugins/syntax/r_syntax.ml

(limited to 'plugins/syntax/r_syntax.ml')

diff --git a/plugins/syntax/r_syntax.ml b/plugins/syntax/r_syntax.ml
new file mode 100644
index 0000000000..4a5972cc71
--- /dev/null
+++ b/plugins/syntax/r_syntax.ml
@@ -0,0 +1,125 @@
+(************************************************************************)
+(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
+(* <O___,, * CNRS-Ecole Polytechnique-INRIA Futurs-Universite Paris Sud *)
+(*   \VV/  **************************************************************)
+(*    //   *      This file is distributed under the terms of the       *)
+(*         *       GNU Lesser General Public License Version 2.1        *)
+(************************************************************************)
+
+(*i $Id$ i*)
+
+open Pp
+open Util
+open Names
+open Pcoq
+open Topconstr
+open Libnames
+
+exception Non_closed_number
+
+(**********************************************************************)
+(* Parsing R via scopes                                               *)
+(**********************************************************************)
+
+open Libnames
+open Rawterm
+open Bigint
+
+let make_dir l = make_dirpath (List.map id_of_string (List.rev l))
+let rdefinitions = make_dir ["Coq";"Reals";"Rdefinitions"]
+let make_path dir id = Libnames.make_path dir (id_of_string id)
+
+let r_path = make_path rdefinitions "R"
+
+(* TODO: temporary hack *)
+let make_path dir id = Libnames.encode_con dir (id_of_string id)
+
+let r_kn = make_path rdefinitions "R"
+let glob_R = ConstRef r_kn
+let glob_R1 = ConstRef (make_path rdefinitions "R1")
+let glob_R0 = ConstRef (make_path rdefinitions "R0")
+let glob_Ropp = ConstRef (make_path rdefinitions "Ropp")
+let glob_Rplus = ConstRef (make_path rdefinitions "Rplus")
+let glob_Rmult = ConstRef (make_path rdefinitions "Rmult")
+
+let two = mult_2 one
+let three = add_1 two
+let four = mult_2 two
+
+(* Unary representation of strictly positive numbers *)
+let rec small_r dloc n =
+  if equal one n then RRef (dloc, glob_R1)
+  else RApp(dloc,RRef (dloc,glob_Rplus),
+            [RRef (dloc, glob_R1);small_r dloc (sub_1 n)])
+
+let r_of_posint dloc n =
+  let r1 = RRef (dloc, glob_R1) in
+  let r2 = small_r dloc two in
+  let rec r_of_pos n =
+    if less_than n four then small_r dloc n
+    else
+      let (q,r) = div2_with_rest n in
+      let b = RApp(dloc,RRef(dloc,glob_Rmult),[r2;r_of_pos q]) in
+      if r then RApp(dloc,RRef(dloc,glob_Rplus),[r1;b]) else b in
+  if n <> zero then r_of_pos n else RRef(dloc,glob_R0)
+
+let r_of_int dloc z =
+  if is_strictly_neg z then
+    RApp (dloc, RRef(dloc,glob_Ropp), [r_of_posint dloc (neg z)]) 
+  else
+    r_of_posint dloc z
+
+(**********************************************************************)
+(* Printing R via scopes                                              *)
+(**********************************************************************)
+
+let bignat_of_r =
+(* for numbers > 1 *)
+let rec bignat_of_pos = function
+  (* 1+1 *)
+  | RApp (_,RRef (_,p), [RRef (_,o1); RRef (_,o2)])
+      when p = glob_Rplus & o1 = glob_R1 & o2 = glob_R1 -> two
+  (* 1+(1+1) *)
+  | RApp (_,RRef (_,p1), [RRef (_,o1);
+      RApp(_,RRef (_,p2),[RRef(_,o2);RRef(_,o3)])])
+      when p1 = glob_Rplus & p2 = glob_Rplus &
+           o1 = glob_R1 & o2 = glob_R1 & o3 = glob_R1 -> three
+  (* (1+1)*b *)
+  | RApp (_,RRef (_,p), [a; b]) when p = glob_Rmult ->
+      if bignat_of_pos a <> two then raise Non_closed_number;
+      mult_2 (bignat_of_pos b)
+  (* 1+(1+1)*b *)
+  | RApp (_,RRef (_,p1), [RRef (_,o); RApp (_,RRef (_,p2),[a;b])])
+      when p1 = glob_Rplus & p2 = glob_Rmult & o = glob_R1  -> 
+      if bignat_of_pos a <> two then raise Non_closed_number;
+        add_1 (mult_2 (bignat_of_pos b))
+  | _ -> raise Non_closed_number
+in
+let bignat_of_r = function
+  | RRef (_,a) when a = glob_R0 -> zero
+  | RRef (_,a) when a = glob_R1 -> one
+  | r -> bignat_of_pos r
+in
+bignat_of_r
+
+let bigint_of_r = function
+  | RApp (_,RRef (_,o), [a]) when o = glob_Ropp ->
+      let n = bignat_of_r a in
+      if n = zero then raise Non_closed_number;
+      neg n
+  | a -> bignat_of_r a
+
+let uninterp_r p =
+  try
+    Some (bigint_of_r p)
+  with Non_closed_number ->
+    None
+
+let _ = Notation.declare_numeral_interpreter "R_scope"
+  (r_path,["Coq";"Reals";"Rdefinitions"])
+  r_of_int
+  ([RRef(dummy_loc,glob_Ropp);RRef(dummy_loc,glob_R0);
+    RRef(dummy_loc,glob_Rplus);RRef(dummy_loc,glob_Rmult);
+    RRef(dummy_loc,glob_R1)],
+    uninterp_r,
+    false)
-- 
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