I understand. But as you seem to hint at, it seems that "declarative" logic is still an imperative concern due to insufficient specification of the declarative

I understand. But as you seem to hint at, it seems that "declarative" logic is still an imperative concern due to insufficient specification of the declarative framework. Which is fine in some cases. It is still control flow at a somewhat meta level. But taking the example of a declarative definition of a UI tree, changing node identity using "declarative" if statements seems like a breach or even a smell from a declarative point of view. The same way, for eachs are not necessary in the declarative layer. That can just be array iteration in the imperative/data layer.