XML Schema 1.0 and Relax NG Only Partially Support Context-FreeGrammars

["Costello, Roger L." <costello@mitre.org>]

Hi Folks,

Did you know that neither XML Schema 1.0 nor Relax NG has the power to express this very simple grammar:

	The content of BookStore shall be N Book elements
	followed by N Magazine elements.

That is, BookStore must contain an equal number of Book and Magazine elements.

It's true. 

Neither XML Schema 1.0 nor Relax NG can express that basic context-free grammar. 

That's sad.

More ... http://xfront.com/XML-Schema-1-0-and-Relax-NG-Partially-Support-Context-Free-Grammars.pdf

/Roger