2 ms·

Not a new terminology. Lisp uses "nil", which is '(), the empty list. Objective-C uses nil as a null pointer to which messages may be sent. Probably others too

• kazinator 10y ago
  The value, under conventional evaluation, of the expression '() is (), which is the empty list. This '() expression itself is the object (quote ()) which is anything but nil. The nil-()-false correspondence is only specific to the Lisp dialects which are close to the original tree. In Scheme, an empty list is indeed (), and this object also the terminating atom of a list. However, the object isn't a symbol at all, let alone the symbol nil. Moreover, the object isn't a Boolean false; Scheme has #f for that.