class Sass::Tree::Visitors::DeepCopy

def visit_prop(node)
  node.name = node.name.map {|c| c.is_a?(Sass::Script::Tree::Node) ? c.deep_copy : c}
  node.value = node.value.map {|c| c.is_a?(Sass::Script::Tree::Node) ? c.deep_copy : c}
  yield
end