# File lib/rbot/core/utils/filters.rb, line 103
    def register_filter(name, group=nil, &block)
      raise "No block provided" unless block_given?
      @filters ||= {}
      tlkey = global_filter_name(name, group)
      key = name.to_sym
      if has_filter?(tlkey)
        debug "Overwriting filter #{tlkey}"
      end
      @filters[tlkey] = DataFilter.new(&block)
      if group
        gkey = group.to_sym
        @filter_group ||= {}
        @filter_group[gkey] ||= {}
        if @filter_group[gkey].key?(key)
          debug "Overwriting filter #{key} in group #{gkey}"
        end
        @filter_group[gkey][key] = @filters[tlkey]
      end
    end