If f were deleted, it would still be in memory unless you explicitly call ns-remove to clean it up. In practice, this is rarely an issue, but I do wish the experience was a little cleaner there.

The same things do apply to integers, but if you use them at the top level (outside a function) then they will be dereferenced immediately (there is no delayed function body to wait for) and so you will get the initial value only once. If you want to enforce a delay, you can use (var x) or the shorthand #’x and later derefence that with @