Odd result from arithmetic with nil

[Steve Heller <steve@...>]

Hi all,

I have some code that creates an object of a date type
(very similar to the one from PIL) and then subtracts
it from nil. I would expect this to raise the "attempt
to perform arithmetic on a nil value" error, but it
doesn't; instead, I get a result of nil. Does this
make any sense?

I can post code if it would help.