But these ideas of declarative frameworks supporting databinding are old, and have been implemented many times in many heterogeneous frameworks and platforms over the past two decades (probably longer, but I don't have context).
I don't have the context either, but according to the people behind databinding on Android, the previous databinding frameworks are usually pretty slow.
They focused on making it run fast by making it compile to bytecode and make the same minimal calls you would make in java .
It is true that it is not a new idea at all though
