Content model probs

Leigh Dodds ldodds at
Fri May 14 15:51:03 BST 1999


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?



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.

    "Never Do With More, What Can Be Achieved With Less"
				---William of Occam
Leigh Dodds                             Eml:  ldodds at
ingenta ltd                             Tel:  +44 1225 826619
BUCS Building, University of Bath       Fax:  +44 1225 826283

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