A generic preprocessing tactic zify for (r)omega

------------------------------------------------ 

See file PreOmega for more details and/or test-suite/succes/*Omega*.v

The zify tactic performs a Z-ification of your current goal,
transforming parts of type nat, N, positive, taking advantage of many
equivalences of operations, and of the positivity implied by these
types.

Integration with omega and romega:
 (r)omega : the earlier tactics, 100% compatible 
 (r)omega with * : full zify applied before the (r)omega run
 (r)omega with <types>, where <types> is a sub-list of {nat,N,positive,Z}, 
   applies only specific parts of zify (btw "with Z" means take advantage 
   of Zmax, Zmin, Zabs and Zsgn). 

As a particular consequence, "romega with nat" should now be a
close-to-perfect replacement for omega. Slightly more powerful, since
(forall x:nat, x*x>=0) is provable and also slightly less powerful: if
False is somewhere in the hypothesis, it doesn't use it. 

For the moment zify is done in a direct way in Ltac, using rewrite
when necessary, but crucial chains of rewrite may be made reflexive
some day.

Even though zify is designed to help (r)omega, I think it might be 
of interest for other tactics (micromega ?). Feel free to complete
zify if your favorite operation / type isn't handled yet. 


Side-effects: 

- additional results for ZArith, NArith, etc...
- definition of Ple, Plt, Pgt, Pge and notations for them in positive_scope
- romega now start by doing "intros". Since the conclusion will be negated, 
  and this operation will be justified by means of decidability, it helps
  to have as little as possible in the conclusion. 






git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10028 85f007b7-540e-0410-9357-904b9bb8a0f7

1 files changed, 7 insertions, 38 deletions

diff --git a/theories/ZArith/Int.v b/theories/ZArith/Int.v
index 4c9470b36..562000d8f 100644
--- a/theories/ZArith/Int.v
+++ b/theories/ZArith/Int.v
@@ -7,8 +7,8 @@
 (***********************************************************************)
 
 (* Finite sets library.  
- * Authors: Pierre Letouzey and Jean-Christophe Filliâtre 
- * Institution: LRI, CNRS UMR 8623 - Université Paris Sud
+ * Authors: Pierre Letouzey and Jean-Christophe Filliâtre 
+ * Institution: LRI, CNRS UMR 8623 - Université Paris Sud
  *              91405 Orsay, France *)
 
 (* $Id$ *)
@@ -352,46 +352,15 @@ Module MoreInt (I:Int).
   Ltac i2z_refl := 
     i2z_gen;
     match goal with |- ?t => 
-      let e := p2ep t 
-	in 
-	(change (ep2p e); 
-	  apply norm_ep_correct2; 
-	    simpl)
+      let e := p2ep t in 
+      change (ep2p e); apply norm_ep_correct2; simpl
     end.
 
-  Ltac iauto := i2z_refl; auto.
-  Ltac iomega := i2z_refl; intros; romega.
-
-  Open Scope Z_scope.
-
-  Lemma max_spec : forall (x y:Z), 
-    x >= y /\ Zmax x y = x  \/
-    x < y /\ Zmax x y = y.
-  Proof.
-    intros; unfold Zmax, Zlt, Zge.
-    destruct (Zcompare x y); [ left | right | left ]; split; auto; discriminate.
-  Qed.
-
-  Ltac omega_max_genspec x y := 
-    generalize (max_spec x y); 
-    (let z := fresh "z" in let Hz := fresh "Hz" in 
-     set (z:=Zmax x y); clearbody z).
-
-  Ltac omega_max_loop := 
-    match goal with 
-      (* hack: we don't want [i2z (height ...)] to be reduced by romega later... *)
-      | |- context [ i2z (?f ?x) ] => 
-          let i := fresh "i2z" in (set (i:=i2z (f x)); clearbody i); omega_max_loop
-      | |- context [ Zmax ?x ?y ] => omega_max_genspec x y; omega_max_loop
-      | _ => intros
-    end.
-
-  Ltac omega_max := i2z_refl; omega_max_loop; try romega.
+  (* i2z_refl can be replaced below by (simpl in *; i2z). 
+     The reflexive version improves compilation of AVL files by about 15%  *)
   
-  Ltac false_omega := i2z_refl; intros; romega.
-  Ltac false_omega_max := elimtype False; omega_max.
+  Ltac omega_max := i2z_refl; romega with Z.
 
-  Open Scope Int_scope.
 End MoreInt.