X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fcomponents%2Fng_kernel%2FnReference.ml;h=bb560bfd6349161810d9a0fd05a4b83e9d286f0c;hb=b41bbbe640d020d2c3ac59cd0398464cd7cf7e41;hp=e209d05bef8e8d3c28b13093addee5f4be070b69;hpb=2c01ff6094173915e7023076ea48b5804dca7778;p=helm.git

diff --git a/matita/components/ng_kernel/nReference.ml b/matita/components/ng_kernel/nReference.ml
index e209d05be..bb560bfd6 100644
--- a/matita/components/ng_kernel/nReference.ml
+++ b/matita/components/ng_kernel/nReference.ml
@@ -30,6 +30,10 @@ let compare (Ref (u1,s1)) (Ref (u2,s2)) =
   if res = 0 then compare s1 s2 else res
 ;;
 
+let hash (Ref (uri,spec)) =
+ Hashtbl.hash spec + NUri.hash uri
+;;
+
 module OrderedStrings =
  struct
   type t = string