在运行时动态创建后备委托

Question

I'm trying to setup C# code to automatically create dummy or fallback delegates for methods that get called by an IronPython script and that are not explicitly implemtented, yet.

Say there's a script that calls the non-static C# class method "MoveTo" which isn't implemented in the corresponding class yet. Usually, in case it exists, it is added to the script's scope by creating a corresponding delegate instance that is given to the scope by a call to "SetVariable" with the name of the Method and the delegate instance. That works fine for methods that already are implemented.

In case the method is not yet implemented the call shall not fail but instead be redirected to a dummy method that gracefully handles the call and pretends successful execution (which is to be considered uncritical in my specific case).

The problem is: the methods invoked by the IronPython script have a wide range of signatures (actually they can have any possible kind of signature). Therefore I'd like to dynamically create a fallback delegate that gets the same signature of the called method and hence "catches" every call to not yet implemented methods.

Do you guys have any idea on how I can achieve this goal?

Answer 1

You should be able to create a catch-all method that takes any number/type of args:

object Fallback([ParamDictionary]IDictionary<object, object> kwargs, params object[] args) {
  return null; // or whatever
}

(Sadly, this is backwards from the normal Python way of writing a similar function: def foo(*args, **kwargs): .)

If you don't use keywords args, you can drop that and just use params :

object Fallback(params object[] args) {
  return null; // or whatever
}

Then use .SetVariable("whatever", Fallback) to make it the fallback method.