Arbitrary "EventOrderingFunction"

[maxitg]

The problem

We now only have a limited scope of what we can do with "EventOrderingFunction".

There are only a few fixed values, and specifying an arbitrary order is not possible.

Possible solution

The goal here is to accept arbitrary functions that would accept a partial evolution object and a list of matches and return the next match that should be evaluated.

It's not clear if it's even possible to make this reasonably efficient. Plus, it won't work with the C++ code without serious WSTP magic.

It might be reasonable to implement in the WL code, though.