xml-dev - RE: Will XML change the character of W3C?

[Sean McGrath <sean@digitome.com>]

At 06:08 AM 10/18/00 -0700, Sam Hunting wrote:

>And "but for" SGML, neither HTML nor XML would exist. If you won't
>learn your history as taught by people who were present at the
>creation, like Len Bullard, try reading the XML Spec -- the first line
>of the abstract reads "The Extensible Markup Language (XML) is a subset
>of SGML..."

Ah, but it ain't that simple by a long shot.

1) HTML (according to TBL's book) was designed to "look like" SGML.
This is different from being SGML. (I no longer have the book handy
but I believe the "look like SGML" bit occurs somewhere around page
40 or so. Anybody got a copy handy who can dig out a full reference?).

2) HTML is not not now and never was, an SGML application. Ever try
feeding a general entity reference to a web browser? Ever try getting
a html editor to create a CDATA section? HTML browsers skip
over tags they don't recognise. Where in the SGML standard does
it say that you can do that?

3) XML is an SGML application only after you change SGML a bit.
Many - not all - but many SGML tools that predate this, um, adaption
of the SGML standard will not process XML correctly. (Most software
based on James Clarks awesome SP engine will. Most of the rest
won't.)

3) SGML is an awesome intellectual feat with some really brilliant
ideas but the standard is soooooo general that pretty much anything
can be termed "SGML" if you hold your mouth right. Heck, I remember
somebody posting details on comp.text.sgml years back
about how to make  RTF (yes RTF) parse as an SGML instance!

I believe that without SGML we would still have the
technical equivalent of HTML (perhaps derived from TeX
or troff or something).
Without SGML we would still have the technical equivalent of
XML (perhaps s-Expressions or Python lists.).

Did SGML make the web happen quicker? Probably. Is the
world a better place for the intellectual effort expended on
and experience gained in developing SGML?. Undoubtedly.
Are SGML, HTML and XML useful things in the primordial
semantic soup of the Web? Absolutely.

Are XML and HTML proper subsets of SGML
in any meaningful sense?

Not in this universe.

regards,
Sean

http://www.pyxie.org - an Open Source XML Processing library for Python