You're conflating declarative and functional. It's declarative, yes. But it's not functional because there are no functions. No inputs, no outputs. It's not a programming language. It's just a config file.
I think functional and declarative are widely regarded as closely related paradigms, certainly you might call a FP program a declarative program. After all a declaration of a value as being derived from some inputs is very similar in concept to an immutable binding in a function or the concepts from functional reactive programming.
Yes, I'd absolutely agree that pure functions are declarative, so "functional" is a subset of "declarative".
But it's a strict subset: config files are declarative without being functional. Raw data is declarative without being functional. One could argue that imperative functions are declarative too: "This C code is the declaration of what steps to execute in what order". So the definition of declarative can be a little fuzzy around the edges, but pure functions are most certainly declarative.
Anyway, QML is most certainly declarative, however it's still not functional because there's no functions.
