[Question] Why doesn't wren support foreign class hierarchies?

[heretique]

Hi, I have a question that arises from a use case I have found while implementing a toy game engine using wren as scripting language. Suppose I have a foreign base Node class and a foreign Spatial class that inherits Node. In wren I will have to duplicate and bind all the base class methods for each foreign subclass I want to expose to wren, adding a lot of error prone boilerplate. What would be the arguments against foreign class inheritance like foreign class Spatial is Node? Is it not supported because lack of time or some other technical impediments? Also what would be the arguments against subclassing from a foreign class directly in wren, something like:

foreign class Node {
...
}

class NodeScript is Node {
...
}

This is also a use case that I found a work around for, but would have been much easier (I think) if I could extend nodes directly in wren (a la Godot GDScript) without going the Unity's "MonoBehaviour" route.

[minirop]

Bob said that he wanted wren to be "leaf only" (wren call C, C does not call wren). I think it's (or was) because of reentrancy problems. I don't know if that changed since (now that C can call wren handles). But I'm 100% for overriding C in wren.

[heretique]

Can someone who has a good understanding of wren's inner workings suggest a way of adding these features (foreign to foreign inheritance and inheritance from foreign). I want to try and add these myself in my fork but I don't have experience writing interpreters. I started reading @munificent's book "Crafting Interpreters", which is really good btw, but I still need a lot of guidance.

[benpop]

I'm currently working around this by making the base class a Wren class with no fields, just methods, and making the underlying structure a tagged union. It's awfully inconvenient, though, and I have to jump through a bit in the call-Wren-from-C interface to confirm the super type for further processing (I really wish there was a C interface for getting the string type name of a slot).

So yeah, put me down as a +1 for this.