FSet/OrderedType now includes an eq_dec, and hence become an extension of DecidableType

 After lots of hesitations, OrderedType now requires this "eq_dec" field, which
 is redundant (can be deduced from "compare"), but allows the subtyping relation
 DecidableType <= OrderedType, and hence WS <= S : ordered sets are now truly
 extensions of weak sets. Of course this change introduces a last-minute
 incompatibility, but:

  - There is a clear gain in term of functionnality / simplicity.
  - FSets 8.2 already needs some adaptations when compared with 8.1, so it's
    the right time to push such incompatible changes.
  - Transition shouldn't be too hard: the old OrderedType still exists under
    the name MiniOrderedType, and functor MOT_to_OT allows to convert from
    one to the other.

 Beware, for a FSetInterface.WS (resp. S) to be coercible to a DecidableType
 (resp. OrderedType), an eq_dec on sets is now required in these interfaces
 and in the implementations. In pratice, it is really easy to build from
 equal and equal_1 and equal_2.

 Some name changes : in FSetFacts, old WFacts now correspond to WFacts_fun,
 while WFacts now expects only one argument (WFacts M := WFacts_fun M.E M).
 Idem with WDecide, WProperties and WEqProperties.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@11693 85f007b7-540e-0410-9357-904b9bb8a0f7

1 files changed, 10 insertions, 11 deletions

diff --git a/theories/FSets/FSetDecide.v b/theories/FSets/FSetDecide.v
index 82c684634c..b7a1deb771 100644
--- a/theories/FSets/FSetDecide.v
+++ b/theories/FSets/FSetDecide.v
@@ -19,10 +19,10 @@
 
 Require Import Decidable DecidableTypeEx FSetFacts.
 
-(** First, a version for Weak Sets *)
+(** First, a version for Weak Sets in functorial presentation *)
 
-Module WDecide (E : DecidableType)(Import M : WSfun E).
- Module F := FSetFacts.WFacts E M.
+Module WDecide_fun (E : DecidableType)(Import M : WSfun E).
+ Module F := FSetFacts.WFacts_fun E M.
 
 (** * Overview
     This functor defines the tactic [fsetdec], which will
@@ -851,15 +851,14 @@ the above form:
 
   End FSetDecideTestCases.
 
-End WDecide.
+End WDecide_fun.
 
 Require Import FSetInterface.
 
-(** Now comes a special version dedicated to full sets. For this 
-    one, only one argument [(M:S)] is necessary. *)
+(** Now comes variants for self-contained weak sets and for full sets.
+    For these variants, only one argument is necessary. Thanks to
+    the subtyping [WS<=S], the [Decide] functor which is meant to be
+    used on modules [(M:S)] can simply be an alias of [WDecide]. *)
 
-Module Decide (M : S).
-  Module D:=OT_as_DT M.E.
-  Module WD := WDecide D M.
-  Ltac fsetdec := WD.fsetdec.
-End Decide.
\ No newline at end of file
+Module WDecide (M:WS) := WDecide_fun M.E M.
+Module Decide := WDecide.