Re: spec. problem: hexBinary, base64Binary value sets disjoint and not disjoint

At 11:57 AM -0400 2009-09-02, Barclay, Daniel wrote:

>  >> Since:
>>>  - the value space of hexBinary is the set of finite-length
>>>     sequences of zero or more binary octets, and
>>>  - the value space of base64Binary is _also_ the set of finite-length
>>>     sequences of zero or more binary octets,
>>>  then those two value spaces are the same set.  Since the are the
>>>  same set, they clearly are not disjoint.
>>
>>  The whole point of the firrst paragraph you quoted is to say that
>>  in the situations like the one you mention (similarly, e.g., for
>>  decimal, double, and float) the members of the value space are
>>  artificially distinguished in the various primitive datatypes
>>  involved.  True for any primitive datatypes whose value spaces as
>>  described appear to have values in common.
>
>Right, but the first paragraph only says that value spaces are
>disjoint for things that "might be thought of as having values in
>common."

Perhaps you jumped into the middle of the spec.  You are quoting a
paragraph from the discussion of order, but before order comes equality
and before equality comes identity.  Since your complaint is about
the apparent identity of values in the two binary-string datatypes,
perhaps we should see what is said in the section on identity rather
than order.  In 2.2.1 the spec says:

   In the identity relation defined herein, values from different
   ˇprimitiveˇ datatypes' ˇvalue spacesˇ are made artificially distinct
   if they might otherwise be considered identical.

Perhaps that more explicitly says what you are looking for.  Once
we make that general statement, do we really need to reiterate it
for every primitive datatype where there might be an overlap with
another?
-- 
Dave Peterson
SGMLWorks!

davep@iit.edu

Received on Thursday, 3 September 2009 01:17:03 UTC