[Bug 3224] Inequality

http://www.w3.org/Bugs/Public/show_bug.cgi?id=3224





------- Comment #3 from davep@iit.edu  2006-09-18 01:45 -------
(In reply to comment #2)
> >> In the second paragraph of 2.2,
> >I believe you mean 2.2.2.
> 
> All my numbering, I'm afraid, was based on section numbers in the "diff"
> version of the document. It didn't occur to me that these might be different
> from the "top copy".

Well, it's 2.2.2 in the diff version.

> >> what does the operator "<>" mean? (Not
> >> equal? Not comparable?) Is it the same as the "/=" operator used in the
> >> second paragraph of the subsequent Note?
> 
> >They are not quite the same, but in this case '<> NaN' should be replaced by
> >'not equal to itself'.
> 
> The real point here is editorial, I think. The operators /= (not equal) and <>
> (incomparable) are defined in 2.2.3, but used in 2.2.2 without explanation.

Well, "<>" does not belong in 2.2.2, and as I said, it needs to be removed.

> >In common usage, "unequal" means "not equal".  Do you really think this needs
> >elaboration?
> 
> There are two possible meanings here: "comparable and not equal", or simply
> "not equal". It's not obvious to me from the context which meaning is intended.

Having eliminated the spurious use of '<>' in this section, "comparability"
shouldn't arise.

> One can probably work out from the context which of these two meanings is
> intended, but in a section where two different operators /= and <> are
> introduced, it's scary to use a word "unequal" that isn't explicitly bound to
> either of them.

Well, with '<>' gone from the section on equality and explained in the section
on order, I hope we no longer have a problem.

> Perhaps I'm conditioned by XPath 2.0, where A=B has three possible outcomes:
> equal (true), not equal (false), and incomparable (error). But many of your
> readers will also be conditioned by XPath.

I hope that pointing out that '?' (not equal) is just the negation of equality,
I trust it's clear that equality is a binary relation.  Similarly I hope that
the explanation of '<>' in 2.2.3 makes it clear that in no case do we expect a
third "error" outcome.

Received on Monday, 18 September 2006 01:45:24 UTC