Integrate a few improvements on typeclasses and Program from the equations branch

and remove equations stuff which moves to a separate plugin.

Classes:
- Ability to define classes post-hoc from constants or inductive types.
- Correctly rebuild the hint database associated to local hypotheses when 
  they are changed by a [Hint Extern] in typeclass resolution.

Tactics and proofs:
- Change [revert] so that it keeps let-ins (but not [generalize]).
- Various improvements to the [generalize_eqs] tactic to make it more robust
  and produce the smallest proof terms possible.
  Move [specialize_hypothesis] in tactics.ml as it goes hand in hand with 
  [generalize_eqs].
- A few new general purpose tactics in Program.Tactics like [revert_until]
- Make transitive closure well-foundedness proofs transparent.
- More uniform testing for metas/evars in pretyping/unification.ml
  (might introduce a few changes in the contribs).

Program:
- Better sorting of dependencies in obligations.
- Ability to start a Program definition from just a type and no obligations, 
  automatically adding an obligation for this type.
- In compilation of Program's well-founded definitions, make the functional a
  separate definition for easier reasoning.
- Add a hint database for every Program populated by [Hint Unfold]s for 
  every defined obligation constant.


git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@12440 85f007b7-540e-0410-9357-904b9bb8a0f7

1 files changed, 4 insertions, 1 deletions

diff --git a/parsing/ppvernac.ml b/parsing/ppvernac.ml
index 8a8248bf4..6449add92 100644
--- a/parsing/ppvernac.ml
+++ b/parsing/ppvernac.ml
@@ -741,7 +741,10 @@ let rec pr_vernac = function
 
 
  | VernacDeclareInstance id ->
-     hov 1 (str"Instance" ++ spc () ++ pr_lident id)
+     hov 1 (str"Existing" ++ spc () ++ str"Instance" ++ spc () ++ pr_lident id)
+
+ | VernacDeclareClass id ->
+     hov 1 (str"Existing" ++ spc () ++ str"Class" ++ spc () ++ pr_lident id)
 
   (* Modules and Module Types *)
   | VernacDefineModule (export,m,bl,ty,bd) ->