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- From: Karl Best <email@example.com>
- To: firstname.lastname@example.org
- Date: Thu, 19 Oct 2000 08:43:32 -0400
> > 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.
> True, but again, that is because the do not implement SGML fully.
XML as initially created was supposed to be a true subset of SGML, but such
things as the optional occurence markers in DTD element declarations, and
the empty tag syntax, were not SGML-conformant. So, to keep XML as a true
subset of SGML, SGML had to be tweaked. The W3C XML committee asked the ISO
SGML committee for some minor changes, and they released a revision (not the
right word, but I can't remember what it was called; some sort of silent
change) to the SGML standard in ~1997.
So, XML is not compliant to ISO 8879-1986 as published in 1986, but it is
compliant with ISO 8879 as it exists after the ~1997 change. So any SGML
parser that supports the later version of SGML should also support XML.
Karl F. Best
OASIS - Director, Technical Operations