[SCL] DTD for XML/SCL

[Bill Andersen]

On Friday, Jan 3, 2003, at 00:52 US/Eastern, John F. Sowa wrote:

> Summary:  XML is an extremely flexible notation that can be used
> and abused in many ways.  For different purposes, different kinds
> of XML markups may be used.  For some purposes, the best way of
> using XML is to provide an escape tag with an attribute that says
> "language=KIF", "language=CGIF", or "language=Z".  I would prefer
> to develop an SCL standard that suggests a couple of encodings in
> a non-normative annex and leaves the way open for other standards
> to choose appropriate encodings for their applications.

I thought that was one function performed by KQML :-D

Seriously, I have no axe to grind one way or the other.  Heck, I don't 
even like XML.  But we need to consider what the abstract syntax is for 
in the first place - at a minimum to drive concrete syntaxes and to 
hang the semantics off of.  So, while verbose, a DTD along the lines 
proposed by Chris is a complete syntactic specification for a CL 
instance language.  It is easy to check that the DTD conforms to the 
abstract syntax and once that is checked, it is *all* that is needed to 
ensure correct parsing (and composition) of formulae.

Not so with John's suggestion.  There, one will have to trust that 
there is a compliant parsing program on the far end of a transmission 
that hopefully conforms to the spec and hopefully to the CL instance 
one believes one is using.

I have sympathy for what John is saying, but I think really that 
parsing efficiency is the least of our problems.  The purported 
advantage of XML is that it provides syntactic transparency.  John's 
suggestion takes that away.

   .bill