[mike_hearn]

What you're asking for is what Compose does (the new Android toolkit). Being pure FP though does have issues. There's no way to get a reference to anything on the screen, so some tasks that are basic and obvious in an OOP toolkit turn into a strange hack in Compose. For instance to focus a text edit you have to create and memoize a "focus requester", pass the "requester" as a parameter to the TextField function, then "launch an effect" and finally you can use the requester to request the focus.

Compare to an OOP toolkit: call edit.focus() when the UI is first displayed and you're done. The reason you need a requester in Compose is because everything is FP and lacks identity, even though there actually is object identity buried deep inside, it's just hidden from you.

The FP model does have some benefits, but I think OP is right and we'll end up with a less radical mixed approach.