{
  "!name": "add_to_old.js",
  "Element": {
    "prototype": {
      "foo": {
        "!span": "39[2:18]-42[2:21]",
        "!type": "+Thing"
      }
    }
  },
  "Thing": {
    "!span": "9[0:9]-14[0:14]",
    "!type": "fn()"
  }
}