By the way, there is at least one additional difference in languages like Python and JavaScript with dynamic variable (not value) scope. In those languages, you can `delete` a variable, which removes the binding from the scope. Pass-by-reference would mean that you could delete a variable from a non-local scope if the variable were passed by reference. (This is not the case; `delete` in these languages merely deleted the local variable binding, as it ought, given that they are pass-by-value.)