I have problems a few random floating statements: "decorators have well-defined semantics in Python" Python lacks well-defined semantics for just about anything

I have problems a few random floating statements: "decorators have well-defined semantics in Python" Python lacks well-defined semantics for just about anything. even simple expressions like 1.0 + 1/2 will evaluate to different things depending on which python version you're using. "Even F# simply isn't powerful enough (never mind OCaml)" evidence, please?