initial version externalized from salama

lib/sof/occurence.rb

@@ -0,0 +1,16 @@
+module Sof
+
+  class Occurence
+    def initialize object , level
+      @object = object
+      @level = level
+      @referenced = nil      
+    end
+    def set_reference r
+      @referenced = r
+    end
+    attr_reader   :object , :referenced
+    attr_accessor :level
+  end
+
+end