Question

I’d like to ask – what is the function doing nil conversion from nil’s to zeroes in elisp?

I’m a newbie and I think I am inventing the wheel with my code:

(defun chgnull (x)
  (if (null x) 0 1))
(mapcar 'chgnull '(1 2 nil))

Search through Emacs sources by keyword “to zero” and such haven’t shown anything relevant.

Answer 1

The expression (or x 0) will evaluate to 0 if x is nil, and x otherwise.