summaryrefslogtreecommitdiff
path: root/theories/FSets/OrderedTypeAlt.v
diff options
context:
space:
mode:
authorGravatar Stephane Glondu <steph@glondu.net>2009-02-01 00:54:40 +0100
committerGravatar Stephane Glondu <steph@glondu.net>2009-02-01 00:54:40 +0100
commitcfbfe13f5b515ae2e3c6cdd97e2ccee03bc26e56 (patch)
treeb7832bd5d412a5a5d69cb36ae2ded62c71124c22 /theories/FSets/OrderedTypeAlt.v
parent113b703a695acbe31ac6dd6a8c4aa94f6fda7545 (diff)
Imported Upstream version 8.2~rc2+dfsgupstream/8.2.rc2+dfsg
Diffstat (limited to 'theories/FSets/OrderedTypeAlt.v')
-rw-r--r--theories/FSets/OrderedTypeAlt.v11
1 files changed, 9 insertions, 2 deletions
diff --git a/theories/FSets/OrderedTypeAlt.v b/theories/FSets/OrderedTypeAlt.v
index 516df0f0..9d179995 100644
--- a/theories/FSets/OrderedTypeAlt.v
+++ b/theories/FSets/OrderedTypeAlt.v
@@ -11,11 +11,12 @@
* Institution: LRI, CNRS UMR 8623 - Université Paris Sud
* 91405 Orsay, France *)
-(* $Id: OrderedTypeAlt.v 10739 2008-04-01 14:45:20Z herbelin $ *)
+(* $Id: OrderedTypeAlt.v 11699 2008-12-18 11:49:08Z letouzey $ *)
Require Import OrderedType.
-(** * An alternative (but equivalent) presentation for an Ordered Type inferface. *)
+(** * An alternative (but equivalent) presentation for an Ordered Type
+ inferface. *)
(** NB: [comparison], defined in [Datatypes.v] is [Eq|Lt|Gt]
whereas [compare], defined in [OrderedType.v] is [EQ _ | LT _ | GT _ ]
@@ -81,6 +82,12 @@ Module OrderedType_from_Alt (O:OrderedTypeAlt) <: OrderedType.
rewrite compare_sym; rewrite H; auto.
Defined.
+ Definition eq_dec : forall x y, { eq x y } + { ~ eq x y }.
+ Proof.
+ intros; unfold eq.
+ case (x ?= y); [ left | right | right ]; auto; discriminate.
+ Defined.
+
End OrderedType_from_Alt.
(** From the original presentation to this alternative one. *)