From: paulNO@... (Paul J. Sanchez)
Date: 2003-08-20T05:45:17+09:00
Subject: Re: NaN and Inifinity

>>>>> "DN" == Dan North <dan@tastapod.com> writes:

    DN> Hi Scott.  It might help to think of NaN meaning "some
    DN> undefined value". Then it makes sense that you can't assign it
    DN> - it's undefined - and also that you can't compare two NaNs -
    DN> they're both undefined so how can you? All you can do is use
    DN> Float.nan? to ask whether the result of what you just did, in
    DN> this case log(-1), is undefined. It also helps explain why it
    DN> isn't, um, defined in Math or Float.

    DN> Cheers, Dan

In statistics, there's a big difference between zero and no data, and
it's nice to be able to initialize variables to indicate the latter.
NaN seems appropriate for this, so it would be nice if it were readily
available instead of having to be manufactured.

--paul