> "you don’t know the real types of variables at runtime", this is just flat wrong. One doesn't know the real type of a variable until runtime. I read the sent

> "you don’t know the real types of variables at runtime", this is just flat wrong. One doesn't know the real type of a variable until runtime. I read the sentence as "you don't know the real types of variable at [the start of] runtime" as opposed to "you don't know the real types of variable *during* runtimes" So I understood the author to mean what you said. Could have been clearer you're right.