[SCL] Representing constraints that go beyond EBNF

[Murray Altheim]

Murray Altheim wrote:
[...]
> Thing is, I *thought* you could already do this in EBNF. If, for example,
> you look at the W3C Recommendation for XML, it has an EBNF grammar for
> XML included in the spec. There certainly seems to me (and I could be
> wrong, but I've been doing this stuff for a long time) as having the
> ability to create unordered collections of tokens (e.g., elements in a
> document). The XML spec even provides the EBNF for the DTD grammar,
> which again, has both ordered (e.g., '+','*') and unordered (',') syntax.

Oops. While the point I'm trying to make is still the same, my example
is not very good. Specifying the syntax of XML documents and DTDs is
what EBNF is being used for, and I'm mixing up the syntax of the meta
language with the syntax of the language.

So the question remains: what parts of SCL can't be expressed in EBNF?
I don't understand SCL's syntax well enough to answer myself, but it
seems to fit the bill.

Murray

...........................................................................
Murray Altheim                         http://kmi.open.ac.uk/people/murray/
Knowledge Media Institute
The Open University, Milton Keynes, Bucks, MK7 6AA, UK                    .

   Q: So exactly how is Ahmad Chalabi different from Manuel Noriega?

      http://www.nationalreview.com/comment/comment-singer062002.asp
      http://www.iraqinews.com/people_chalabi.shtml
      http://truthout.org/docs_03/041103F.shtml

   A: One speaks fluent Arabic, the other Spanish.

     "Noriega took refuge in the Vatican embassy, where US troops played
      hard rock music until Noriega surrendered on January 3, 1990."
      http://www.nationmaster.com/encyclopedia/Manuel-Noriega
      http://www.gwu.edu/~nsarchiv/NSAEBB/NSAEBB2/nsaebb2.htm#3a
      http://www.addictedtowar.com/panama.htm