_dasherize

# File activesupport/lib/active_support/xml_mini.rb, line 164
      def _dasherize(key)
        # $2 must be a non-greedy regex for this to work
        left, middle, right = /\A(_*)(.*?)(_*)\Z/.match(key.strip)[1, 3]
        "#{left}#{middle.tr('_ ', '--')}#{right}"
      end