# File lib/sass/tree/visitors/perform.rb, line 501
  def visit_directive(node)
    node.resolved_value = run_interp(node.value)
    old_in_keyframes, @in_keyframes = @in_keyframes, node.normalized_name == "@keyframes"
    with_environment Sass::Environment.new(@environment) do
      node.children = node.children.map {|c| visit(c)}.flatten
      node
    end
  ensure
    @in_keyframes = old_in_keyframes
  end