[ddjohnson]

Thanks! This is one of the more experimental design choices I made in designing Penzai, but so far I've found it to be quite useful.

The effect system does come with a few sharp edges at the moment if you want to use JAX transformations inside the forward pass of your model (see my reply to Patrick), but I'm hoping to make it more flexible as time goes on. (Figuring out how effect systems should compose with function transformations is a bit nontrivial!)

Please let me know if you run into any issues using Penzai for your model! (Also, most of Penzai's visualization and patching utilities should work with Equinox too, so you shouldn't necessarily need to fully commit to either one.)

[catgary]

This something I’ve thought about in the past, since I messed around with trying to add monads to JAX - I think you made the right call with effect handlers. You might want to take a look at what Koka does, that was the best implementation of effect handlers the last time I checked.