Re: #PCDATA in model group that is not optional and repeatable

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• Previous message: David Megginson: "Re: #PCDATA in model group that is not optional and repeatable"
• In reply to: David Megginson: "Re: #PCDATA in model group that is not optional and repeatable"

> >By the way, you gain nothing by using "+" instead of "*", since
> >#PCDATA can be an empty string.
>
> I know, but why isn't it allowed at all? (or why was it allowed in SGML in
> the first place?)

Because full SGML treats all content models equally, while XML
attaches special restrictions to those with mixed content. Full SGML
also allows relatively useless expressions like

(#PCDATA & foo)*
(#PCDATA)+

and it will let you do many other strange things, as long as your
content model does not become ambiguous.

All the best,

David

-- 
David Megginson                 ak117@freenet.carleton.ca
Microstar Software Ltd.         dmeggins@microstar.com
University of Ottawa            dmeggins@uottawa.ca
        http://www.uottawa.ca/~dmeggins





 Previous message: David Megginson: "Re: #PCDATA in model group that is not optional and repeatable"
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