# File lib/sass/script/interpolation.rb, line 32
    def to_sass(opts = {})
      res = ""
      res << @before.to_sass(opts) if @before
      res << ' ' if @before && @whitespace_before
      res << '#{' unless @originally_text
      res << @mid.to_sass(opts)
      res << '}' unless @originally_text
      res << ' ' if @after && @whitespace_after
      res << @after.to_sass(opts) if @after
      res
    end