# File lib/ruote/svc/dollar_sub.rb, line 155
      def []=(key, value)

        pr, k = extract_prefix(key)
        pr = pr[0, 1]

        if pr == 'f'

          @workitem.set_attribute(k, value)

        elsif @fexp

          @fexp.set_variable(k, value)
        end
      end