# File lib/edi4r/standards.rb, line 151
      def Directory.create( std, params )

        case std
        when 'E' # UN/EDIFACT
          par = {:d0051 => '', 
                 :d0057 => '',
                 :is_iedi => false }.update( params )
        when 'I' # SAP IDocs
          par = { }.update( params )
        else
          raise "Unsupported syntax standard: #{std}"
        end

        if Directory.caching?

          # Use param set as key for caching
          #
          key = par.sort {|a,b| a.to_s <=> b.to_s}.hash
          obj = @@cache[key]
          return obj unless obj.nil?

          obj = new( std, par )
          @@cache[key] = obj # cache & return it

        else
          new( std, par )
        end
      end