Ken MacLeod ken@bitsko.slc.ut.us
22 Apr 2000 15:06:06 -0500

Christian Tismer <tismer@tismer.com> writes:

> "Andrew M. Kuchling" wrote:
> ...
> > To my horror, the two parts of the XML schema WDs are 520K and 360K of
> > HTML; that's huge!  (XML 1.0 is 188K.)  Didn't people want schemas
> > because they thought DTD syntax was too complicated?
> It looks so, yes. But it's all XML, no DTD needed, and it is much
> more powerful and easy to read.  To get a feeling, I suggest to grab
> a demo copy of XMLAuthority at http://www.extensiblity.com and play
> with it. Create a simple document structure, and save it as DTD and
> as Schema.  This is quite impressive and convincing.
> Writing a schema processor would not involve to write a new XML
> parser per se, but you would use an existing, probably
> non-validating parser, maybe one that validates the XSD file.
> But generating the rules from the XSD files is then already
> completely Python's task, since what we generate is a set of rules
> which are used as the validating/processing part for data files
> which make use of that schema.  These rules would be put on top of a
> fast non-validating parser.

I respect the functionality of XML Schema, but to claim its XML
grammar as "more powerful and easy to read" is a big reach.
Domain-specific syntaxes almost always beat out generic or interchange
syntaxes for expressiveness and readability.

That ranks up there with using a DOM interface to your application's
data as one of the biggest misuses of XML.

  -- Ken