XML complexity, namespaces (was WG)

David Megginson david at megginson.com
Fri Mar 19 13:53:11 GMT 1999


Paul Prescod writes:

 > Richard Goerwitz wrote:
 > > 
 > > I come from a small shop that does a lot of SGML work.  Trust me:
 > > SGML is complex and intractable.
 > 
 > <RANT>
 > This is way off topic but I must admit that these characterizations really
 > annoy me.
 > 
 > I can only speak anecdotally: I started using SGML while working
 > for a professor of English as an undergrad. A single programmer
 > (not me) wrote a pretty sophisticated application that converted
 > SGML to HTML and RTF in a couple of months -- almost exactly the
 > same amount of time it would take to do the same for XML.

Actually, many such applications were often written in a few days or
even a few hours.  The interesting thing about SGML is that it was
heavily used in two separate markets at extreme ends of the scale:

1. academia, for large, low-budget projects using free software (like
   Emacs, NSGMLS, Perl, and Jade) or cheap software (like WP7); and

2. government/military/heavy-industry, for large, high-budget projects 
   using extremely expensive commercial software (like ArborText and
   Omnimark).

In general, the academic projects (and there are hundreds of them)
accomplished much more using much less (often just a single PC on a
grad student's desk), but that is partly because they never had to
become too user friendly -- the researchers would work directly with
SGML markup, rather than hiding it behind $20K/seat GUI tools.  The
gov/mil/industry projects spent most of the money trying to hide the
SGML from view -- the processing itself has never been difficult, SGML
or XML.

What SGML missed was the middle part of the document market -- the
$1M-$100M/year companies who couldn't afford all of the customised
user-friendly tools, but didn't have the free time or initiative to
support and maintain their own custom installations.

 > The process was almost identical too: you use a parser from James
 > Clark, pump the data into your favorite scripting language and
 > output it in the other language. The complexity of the input syntax
 > was and is irrelevant to solving that problem.

Almost correct.  One expensive disadvantage of SGML (until WebSGML) is
that it requires full DTD conformance at every stage of production; as
a result, if your production chain consists of ten physical steps,
writing out SGML at each stage, you *must* have DTDs for all of the
intermediate steps.  This one constraint can add $100K or more to a
large enterprise SGML project, since DTD writers are expensive to hire
(and a single, configured DTD becomes heavily obfuscated so that it
can almost never be maintained in-house).


All the best,


David

-- 
David Megginson                 david at megginson.com
           http://www.megginson.com/

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