Again wit da AND and Repetitions

John Cowan cowan at
Sat May 15 20:19:21 BST 1999

Mark McDonald wrote:

> > <!ELEMENT x (a? | b?)>
> > <!ELEMENT a (c,d,e,f,g)>
> > <!ELEMENT b (c,d,e,f,h)>
> > 
> > With an input of elements c, d, e, f, h in element x.

And David Brownell replied:

> Actually, the content model for "x" is in error there, so any
> XML processor is allowed to report an error however rudely it
> chooses to do so.  That content model is "ambigious".

I can only assume that both of you are suffering from brain farts.
Any "x" that contains anything but an "a" or a "b" is obviously
invalid.  You are talking as if the above declarations were:

<!ENTITY % a "(c,d,e,f,g)">
<!ENTITY % b "(c,d,e,f,h)">
<!ELEMENT x (%a;? | %b;?)>

Element declarations refer to lexically apparent objects (elements),
not to mere groups of elements defined by pseudo-BNF.

John Cowan					cowan at
		e'osai ko sarji la lojban.

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