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variation in restrictions related to use of "ref" in XML Schema Part 1

From: Paul Golick <golick@us.ibm.com>
Date: Tue, 10 Apr 2001 07:51:49 -0400
To: www-xml-schema-comments@w3.org
Message-ID: <OF528DE201.6677F22C-ON85256A2A.00410426@raleigh.ibm.com>
While investigating extensibility differences between elements and
attributes, an unexplained variation was discovered.

In XML Schema Part 1, section 3.3.3 item 2.2 states that when "ref" is
present, "default" and "fixed" must be absent.  (The table in section 3.3.2
also has special treatment for "ref".)  However, there is no comparable
restriction resulting from the use of "ref" on attribute declarations and
uses in section 3.2.3 item 3.2; although sections 3.5.4 and 3.5.6 give
reasonable consistency rules.

This prohibition (on specifying "default" or "fixed") on elements can be
avoided by using "name" and "type" instead of "ref".  There is no
comparable prohibition on attribute declarations or uses ("default" or
"fixed" can be specified even if "ref" is used, subject to a consistency
rule).

Was this variation between elements and attributes intentional?

Regards,
Paul Golick

building 655, room A209
5605 Six Forks Road
Raleigh, NC 27609
telephone:  1-919-301-7132
tie line:  352-7132
e-mail:  golick@us.ibm.com
Received on Tuesday, 10 April 2001 07:52:08 GMT

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