From: "David LeBlanc" <>
> A question has arisen about element content. I'm reasonably sure I've read
> that it's illegal for an element to contain itself either directly or
> indirectly. Is this correct, and if so, can someone point me to the relevant
> section of the XML Recommendation please?
No such constraint exists in XML.
SGML provided a facility, the exclusion exception, to all this constraint to be specified.
You can also sepcify it trivially in Schematron.
Topologi's "Editor's Concrete Syntax" uses the SGML '97 facility of "amply-tagged", which
does have the restriction that an element cannot directly contain itself, which allows
an implication policy for ommitted end-tags, see
http://www.topologi.com/resources/pdfs/ECS.pdf
Cheers
Rick Jelliffe
