code: func (s *Script) rawScriptSource(script string) (interface{}, error) {
  	v := strings.TrimSpace(script)
  	if !strings.HasPrefix(v, "{") && !strings.HasPrefix(v, `"`) {
  		v = fmt.Sprintf("%q", v)
  	}
  	raw := json.RawMessage(v)
  	return &raw, nil
  }
docs: // rawScriptSource returns an embeddable script. If it uses a short
  // script form, e.g. "ctx._source.likes++" (without the quotes), it
  // is quoted. Otherwise it returns the raw script that will be directly
  // embedded into the JSON data.