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

At 5:30 PM -0400 2009-09-01, Barclay, Daniel wrote:
>In the XML Schema Definition Language (XSD) 1.1 Part 2: Datatypes CR
>at 
><http://www.w3.org/TR/2009/CR-xmlschema11-2-20090430>http://www.w3.org/TR/2009/CR-xmlschema11-2-20090430, 
>section 2.2.3
>says:
>
>    For purposes of this specification, the value spaces of primitive
>    datatypes are disjoint, even in cases where the abstractions they
>    represent might be thought of as having values in common.
>
>However, the specification goes on to define the value spaces of
>hexBinary and base64Binary to be the same set of values:
>
>Section 3.3.16.1, Value Space (for hexBinary) says:
>
>      The ·value space· of hexBinary is the set of finite-length
>      sequences of zero or more binary octets.  The length of a value
>      is the number of octets.
>
>Section 3.3.17.1, Value Space (for base64Binary) says, identically:
>
>      The ·value space· of base64Binary is the set of finite-length
>      sequences of zero or more binary octets.  The length of a value
>      is the number of octets.
>
>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.
-- 
Dave Peterson
SGMLWorks!

davep@iit.edu