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XML Schema issues resolution

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 12 Sep 2000 12:51:59 +0100
To: Bob Schloss <rschloss@us.ibm.com>
Cc: www-xml-schema-comments@w3.org
Message-ID: <f5bya0x6d5s.fsf@cogsci.ed.ac.uk>
You posted a contribution to the XML Schema comments list on 10 May,
which was assigned the ID LC-112 [1].

We are currently working through all comments we've received on XML
Schema to ensure they have been adequately dealt with, and are
embarassed to find you have so far received no reply.

The Unique Attribution constraint is intended to reconstruct as nearly 
as possible the equivalent constraint in XML 1.0 [2].  As such it
applies entirely at the level of (qualified) element names:  the
matter of types is addressed separately, by the Element Declarations
Consistent constraint [3], which forbids two elements with the same
name but different type from appearing in a content model at all.

We have use the name "Unique Attribution constraint", not "Determinism
constraint", because it does not rule out all non-deterministic
models, e.g. (a|b?)*.

Following comments from you and others, we have reworded the Unique
Attribution constraint as follows:

    A content model must be formed such that during schema validation of
    an element information item sequence, the particle contained directly,
    indirectly or implicitly therein with which to attempt to
    schema-validate each item in the sequence in turn can be uniquely
    determined without examining the content or attributes of that item,
    and without any information about the items in the remainder of the

A formal specification in terms of finite-state automata has also
been added to the discussion in Appendix F.

Could you confirm that this modification and the discussion above
addresses your concerns to your satisfaction?



[1] http://www.w3.org/XML/Group/xmlschema-current/lcissues.html#determinism
[2] http://www.w3.org/TR/REC-xml#determinism
[3] http://www.w3.org/TR/xmlschema-1/#cos-element-consistent
  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
          W3C Fellow 1999--2001, part-time member of W3C Team
     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
	    Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
		     URL: http://www.ltg.ed.ac.uk/~ht/
Received on Tuesday, 12 September 2000 07:52:02 UTC

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