I think he's asking for a special nil object that is not compatible with integers (nor with other objects).
I.e. x != UNDEFINED for all numbers (and objects), and 17 + UNDEFINED ==> some exception.
/ Niels Möller ()
Previous text:
2003-01-22 07:04: Subject: Re: zero_type() & UNDEFINED and _typeof()
Well... It means that I cannot test something for equality to UNDEFINED and expect correct results (when value is present but is integer zero).
So UNDEFINED by itself is useless, unless tested by zero_type().
It would be nice to have universal "void" value, which would be tested like (value == VOID) where 0 is guaranteed not to be VOID (because it actually isn't).
I don't exactly understand what you want to have - do you want something that means "NULL" but which isn't zero and if you do NULL == <zero or variable with value zero> to always return false?
/ David Hedbor