From af95d9e68e803244c919fee21877a38ef13c863b Mon Sep 17 00:00:00 2001
From: Claudio Sacerdoti Coen <claudio.sacerdoticoen@unibo.it>
Date: Fri, 13 Jul 2007 18:04:35 +0000
Subject: [PATCH] Dirty patch by Zack: natural numbers of Matita are now
 pretty-printed as numbers. Eureka.

---
 .../acic_content/termAcicContent.ml           | 21 +++++++++++--------
 .../software/components/cic/libraryObjects.ml | 16 ++++++++++++++
 .../components/cic/libraryObjects.mli         |  2 ++
 3 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/helm/software/components/acic_content/termAcicContent.ml b/helm/software/components/acic_content/termAcicContent.ml
index eaa532590..9a30b50fb 100644
--- a/helm/software/components/acic_content/termAcicContent.ml
+++ b/helm/software/components/acic_content/termAcicContent.ml
@@ -123,7 +123,7 @@ let ast_of_acic0 term_info acic k =
           k s, k t))
     | Cic.AAppl (aid,(Cic.AConst _ as he::tl as args))
     | Cic.AAppl (aid,(Cic.AMutInd _ as he::tl as args))
-    | Cic.AAppl (aid,(Cic.AMutConstruct _ as he::tl as args)) ->
+    | Cic.AAppl (aid,(Cic.AMutConstruct _ as he::tl as args)) as t ->
        let last_n n l =
          let rec aux =
           function
@@ -143,14 +143,17 @@ let ast_of_acic0 term_info acic k =
                idref aid (Ast.Appl (l@tl))
            | l -> idref aid (Ast.Appl l)
        in
-       let deannot_he = Deannotate.deannotate_term he in
-       if CoercDb.is_a_coercion' deannot_he && !Acic2content.hide_coercions
-       then
-         match CoercDb.is_a_coercion_to_funclass deannot_he with
-         | None -> idref aid (last_n 1 (List.map k tl))
-         | Some i -> idref aid (last_n (i+1) (List.map k tl))
-       else
-        idref aid (Ast.Appl (List.map k args))
+       (match LibraryObjects.destroy_nat t with
+       | Some n -> idref aid (Ast.Num (string_of_int n, -1))
+       | None ->
+           let deannot_he = Deannotate.deannotate_term he in
+           if CoercDb.is_a_coercion' deannot_he && !Acic2content.hide_coercions
+           then
+             (match CoercDb.is_a_coercion_to_funclass deannot_he with
+             | None -> idref aid (last_n 1 (List.map k tl))
+             | Some i -> idref aid (last_n (i+1) (List.map k tl)))
+           else
+             idref aid (Ast.Appl (List.map k args)))
     | Cic.AAppl (aid,args) ->
         idref aid (Ast.Appl (List.map k args))
     | Cic.AConst (id,uri,substs) ->
diff --git a/helm/software/components/cic/libraryObjects.ml b/helm/software/components/cic/libraryObjects.ml
index e2f5fd363..7e1dc626f 100644
--- a/helm/software/components/cic/libraryObjects.ml
+++ b/helm/software/components/cic/libraryObjects.ml
@@ -200,6 +200,14 @@ let nat_URI = UriManager.uri_of_string "cic:/matita/nat/nat/nat.ind"
 let zero = Cic.MutConstruct (nat_URI,0,1,[])
 let succ = Cic.MutConstruct (nat_URI,0,2,[])
 
+let is_zero = function
+  | Cic.AMutConstruct (_, uri, 0, 1, _) when UriManager.eq uri nat_URI -> true
+  | _ -> false
+
+let is_succ = function
+  | Cic.AMutConstruct (_, uri, 0, 2, _) when UriManager.eq uri nat_URI -> true
+  | _ -> false
+
 let build_nat n =
   if n < 0 then assert false;
   let rec aux = function
@@ -207,3 +215,11 @@ let build_nat n =
     | n -> Cic.Appl [ succ; (aux (n - 1)) ]
   in
   aux n
+
+let destroy_nat annterm =
+  let rec aux acc = function
+    | Cic.AAppl (_, [he ; tl]) when is_succ he -> aux (acc + 1) tl
+    | t when is_zero t -> Some acc
+    | _ -> None in
+  aux 0 annterm
+
diff --git a/helm/software/components/cic/libraryObjects.mli b/helm/software/components/cic/libraryObjects.mli
index 8aacd8da3..bb742f172 100644
--- a/helm/software/components/cic/libraryObjects.mli
+++ b/helm/software/components/cic/libraryObjects.mli
@@ -65,3 +65,5 @@ val true_URI : unit -> UriManager.uri option
 val absurd_URI : unit -> UriManager.uri option
 
 val build_nat : int -> Cic.term
+val destroy_nat : Cic.annterm -> int option
+
-- 
2.39.2