Thank you for your explanation.
Yes, my explanation wasn’t very good here. modifyPlus1 is just a toy example to show how to use interpose itself, and you’re right that in this case, simply using local is sufficient. Rather, what I mainly should have asked about was logWriteDB. This is close to the code I showed in another thread, and it’s something used to take logs in a local, monkey-patch-like manner. By using interpose in this way, you can set up hooks for general effects in a unified manner, which I consider one of the convenient features of the effect system. So I’m hoping we can do this in bluefin as well. I’ll read the responses in that thread and think about it a bit more. Thank you.
It seems I was mistaken about it being just an IORef. Good to hear that it depends on the effect (especially interesting in the case of coroutines). Thanks!