From 55158e2bd190607dbfccc01027c69c660cc82943 Mon Sep 17 00:00:00 2001
From: Claudio Sacerdoti Coen <claudio.sacerdoticoen@unibo.it>
Date: Thu, 17 Nov 2005 18:37:38 +0000
Subject: [PATCH] "Parallel" rewriting in a list of hypothesis and in the
 conclusion is now allowed.

---
 helm/ocaml/tactics/equalityTactics.ml | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/helm/ocaml/tactics/equalityTactics.ml b/helm/ocaml/tactics/equalityTactics.ml
index 20dede31e..e519827f2 100644
--- a/helm/ocaml/tactics/equalityTactics.ml
+++ b/helm/ocaml/tactics/equalityTactics.ml
@@ -23,8 +23,8 @@
  * http://cs.unibo.it/helm/.
  *)
  
-let rewrite_tac ~direction ~pattern equality =
- let rewrite_tac ~direction ~pattern:(wanted,hyps_pat,concl_pat) equality status
+let rec rewrite_tac ~direction ~pattern equality =
+ let _rewrite_tac ~direction ~pattern:(wanted,hyps_pat,concl_pat) equality status
  =
   let module C = Cic in
   let module U = UriManager in
@@ -37,6 +37,22 @@ let rewrite_tac ~direction ~pattern equality =
   let proof,goal = status in
   let curi, metasenv, pbo, pty = proof in
   let (metano,context,gty) as conjecture = CicUtil.lookup_meta goal metasenv in
+  match hyps_pat with
+     he::(_::_ as tl) ->
+       PET.apply_tactic
+        (Tacticals.then_
+          (rewrite_tac ~direction
+           ~pattern:(None,[he],Cic.Implicit None) equality)
+          (rewrite_tac ~direction ~pattern:(None,tl,concl_pat) equality)
+        ) status
+   | [_] as hyps_pat when concl_pat <> Cic.Implicit None ->
+       PET.apply_tactic
+        (Tacticals.then_
+          (rewrite_tac ~direction
+           ~pattern:(None,hyps_pat,Cic.Implicit None) equality)
+          (rewrite_tac ~direction ~pattern:(None,[],concl_pat) equality)
+        ) status
+   | _ ->
   let arg,dir2,tac,concl_pat,gty =
    match hyps_pat with
       [] -> None,true,PT.exact_tac,concl_pat,gty
@@ -73,7 +89,7 @@ let rewrite_tac ~direction ~pattern equality =
                ProofEngineStructuralRules.clear dummy
               ]),
          pat,gty
-    | _ -> assert false (*CSC: not implemented yet!*)
+    | _::_ -> assert false
   in
   let if_right_to_left do_not_change a b = 
     match direction with
@@ -163,7 +179,7 @@ let rewrite_tac ~direction ~pattern equality =
   in
    (proof',goals)
  in
-  ProofEngineTypes.mk_tactic (rewrite_tac ~direction ~pattern equality)
+  ProofEngineTypes.mk_tactic (_rewrite_tac ~direction ~pattern equality)
   
  
 let rewrite_simpl_tac ~direction ~pattern equality =
-- 
2.39.2