RBAC / Extension Guard for functions that take in an action

gistfile1.txt

// Extension functions
// Generic Programming

extension XFunctionGuard<T extends Function> on T {
  T callWithGuard(String action) {
    if (action != "callable") {
      throw Exception();
    }
    return this.call;
  }
}

void main() async {
  Function hi = () => print("hi");
  Future<String> lateHi() async {
    await Future.delayed(Duration(seconds: 1), (){});
    return "hi, Late!";
  }
  hi.callWithGuard("callable")();
  print(await lateHi.callWithGuard("callable2")());
}