better max function (instead of @) for combining universes

[helm.git] / helm / software / components / ng_kernel / nCicEnvironment.ml

diff --git a/helm/software/components/ng_kernel/nCicEnvironment.ml b/helm/software/components/ng_kernel/nCicEnvironment.ml
index 0ddd3601db02f4502f0cc0d9780adaff6b74584a..9cad0554cea2381845aaf63a654e008507481dbb 100644 (file)
--- a/helm/software/components/ng_kernel/nCicEnvironment.ml
+++ b/helm/software/components/ng_kernel/nCicEnvironment.ml
@@ -21,6 +21,12 @@ exception BadConstraint of string Lazy.t;;
 
 let type0 = []
 
+let max l1 l2 =
+ HExtlib.list_uniq ~eq:(fun (b1,u1) (b2,u2) -> b1=b2 && NUri.eq u1 u2)
+  (List.sort (fun (b1,u1) (b2,u2) ->
+    let res = compare b1 b2 in if res = 0 then NUri.compare u1 u2 else res)
+      (l1 @ l2))
+
 let le_constraints = ref [] (* strict,a,b *)
 
 let rec le_path_uri avoid strict a b =
@@ -41,7 +47,15 @@ let universe_leq a b =
      raise (BadConstraint
       (lazy "trying to check if a universe is less or equal than an inferred universe"))
 
-let universe_eq a b = universe_leq b a && universe_leq a b
+let universe_eq a b = 
+  match a,b with 
+  | [(false,_)], [(false,_)] -> universe_leq b a && universe_leq a b
+  | _, [(false,_)]
+  | [(false,_)],_ -> false
+  | _ ->
+     raise (BadConstraint
+      (lazy "trying to check if two inferred universes are equal"))
+;;
 
 let pp_constraint b x y =  
   NUri.name_of_uri x ^ (if b then " < " else " <= ") ^ NUri.name_of_uri y