# File lib/sass/tree/visitors/convert.rb, line 161
  def visit_mixindef(node)
    args =
      if node.args.empty?
        ""
      else
        '(' + node.args.map do |v, d|
          if d
            "#{v.to_sass(@options)}: #{d.to_sass(@options)}"
          else
            v.to_sass(@options)
          end
        end.join(", ") + ')'
      end
          
    "#{tab_str}#{@format == :sass ? '=' : '@mixin '}#{dasherize(node.name)}#{args}#{yield}"
  end