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Re: Meaning of block="substitution"?

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 03 Dec 2000 14:10:25 +0000
To: "Roger L. Costello" <costello@mitre.org>
Cc: xmlschema-dev@w3.org
Message-ID: <f5b3dg5sii6.fsf@cogsci.ed.ac.uk>
"Roger L. Costello" <costello@mitre.org> writes:

> Hi Folks,
> 
> This question is with respect to block="substitution".
> 
> Example.  Consider this head element declaration:
> 
> <element name="subway" type="string" block="substitution"/>
> 
> Does the block="substitution" mean that it is invalid to even declare a
> substitutionGroup element, such as:
> 
> <element name="train" substitutionGroup="a:subway" type="string"/>
> 
> Or, does it simply mean that in an instance document <subway> cannot be
> substituted by train?  That is, does it mean that it is valid to declare
> substitutionGroup elements but it is invalid to use them in instance
> documents?

The latter:

  "The supplied values for {disallowed substitutions} determine
  whether an element declaration appearing in a content model will be
  prevented from additionally validating elements which . . . are in
  the substitution group headed by the declared element. . . ." [1]

ht

[1] http://www.w3.org/TR/xmlschema-1/#Element_Declaration_details


-- 
  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 Sunday, 3 December 2000 09:10:28 GMT

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