class Sass::Tree::RootNode

def to_src(opts, fmt)
  Sass::Util.enum_cons(children + [nil], 2).map do |child, nxt|
    child.send("to_#{fmt}", 0, opts) +
      if nxt &&
          (child.is_a?(CommentNode) && child.line + child.value.count("\n") + 1 == nxt.line) ||
          (child.is_a?(ImportNode) && nxt.is_a?(ImportNode) && child.line + 1 == nxt.line) ||
          (child.is_a?(VariableNode) && nxt.is_a?(VariableNode) && child.line + 1 == nxt.line)
        ""
      else
        "\n"
      end
  end.join.rstrip + "\n"
end