* lib/rss, test/rss, sample/rss: backported from CVS HEAD.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@7509 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/rss/parser.rb

@@ -348,6 +348,13 @@ module RSS
         end
 
         if @do_validate and required and val.nil?
+          unless a_uri.include?(nil)
+            for prefix, uri in ns
+              if a_uri.include?(uri)
+                a_name = "#{prefix}:#{a_name}"
+              end
+            end
+          end
           raise MissingAttributeError.new(tag_name, a_name)
         end
 
@@ -357,10 +364,9 @@ module RSS
       previous = @last_element
       next_element = klass.send(:new, *args)
       next_element.do_validate = @do_validate
-      setter = ""
-      setter << "#{klass.required_prefix}_" if klass.required_prefix
-      setter << "#{tag_name}="
-      @last_element.send(setter, next_element)
+      prefix = ""
+      prefix << "#{klass.required_prefix}_" if klass.required_prefix
+      previous.__send__(:set_next_element, prefix, tag_name, next_element)
       @last_element = next_element
       @proc_stack.push Proc.new { |text, tags|
         p(@last_element.class) if DEBUG