But that's not the point; a functional style can be achieved in any language as long as it has functions.
Additionally you should know that functional programming is a lie. Your computer is an imperative machine with no understanding of functional programming. The compiler transforms your functional program into an imperative one.
Yet you program a register machine as if it were a stack machine all the time without batting an eyelid!
This is your original argument. I said that FP programs offer none of the said guarantees because they are at it's core compiled into imperative programs... You responded with a statement about a stack machine being an abstraction over a "register machine." How does the stack machine statement move your original argument forward...? We're getting side tracked here...