Content model probs

[tconway at walldata.com]

You could define something like
<!ELEMENT tag (#PCDATA | XAndOrY)
<!ELEMENT XAndOrY (X?, Y*)


This requires one more element than you wanted, but it approximates what you
were looking for.

Tomás.

	-----Original Message-----
	From:	Leigh Dodds [SMTP:ldodds at ingenta.com]
	Sent:	Friday, May 14, 1999 2:50 PM
	To:	xml-dev
	Subject:	Content model probs

	Hi,

	I've being toying with a content model now and I think my brain 
	must be overloaded because I can't think of the best way to 
	format it so it'll parse.

	Basically I want to say that a tag should:

	1. Contain #PCDATA, *OR*
	2. an optional tag X followed by zero or more occurences of tag Y

	I had thought something like : (#PCDATA|(X?, Y*)
	but that doesn't seem to parse.

	At the moment I've had to settle on (#PCDATA|X|Y)* just so I 
	can continue working, and manually check for the moment that 
	I'm building documents which I consider legal.

	Any of you XML gurus got any suggestions?

	Thanks!

	L.

	p.s. A variation I'd also like to consider is changing the model 
	such that 2. (above) becomes:

	2. zero or more occurences of X, followed by zero or more occurences

	of Y.

	In this case X,Y can be interspersed. In the former, X *must* be
before 
	Y if its provided.

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	Leigh Dodds                             Eml:  ldodds at ingenta.com
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