code: func (r *router) URLFor(name string, params ...interface{}) string {
  	route := r.findRoute(name)
  
  	if route == nil {
  		panic("route not found")
  	}
  
  	var args []string
  	for _, param := range params {
  		switch v := param.(type) {
  		case int:
  			args = append(args, strconv.FormatInt(int64(v), 10))
  		case string:
  			args = append(args, v)
  		default:
  			if v != nil {
  				panic("Arguments passed to URLFor must be integers or strings")
  			}
  		}
  	}
  
  	return route.URLWith(args)
  }
docs: // URLFor returns the url for the given route name.