Couldn't XML allow and ignore omitted tag minimization
[I'm forwarding the following message at the request of Paul Grosso,
who had trouble getting through to the list and then had to go on the
road for a few days. Those of you who persist in mindlessly replying
to the poster instead of the list will please note that the poster in
this case is Paul, not me.]
Date: Fri, 28 Feb 97 17:36:53 CST
From: email@example.com (Paul Grosso)
Subject: Couldn't XML allow and ignore omitted tag minimization
When this was brought up at Tuesday's SGML Open Technical Committee
meeting, Jon suggested I post this despite the fact that this issue
was decided once (and despite the fact that Jon appeared to disagree
with me on this).
Although I thought I was following all our discussions, I missed
the fact that XML as currently defined would not parse a DTD
that contained omitted tag minimization (those "- -" and "- O"
things in element declarations).
I understand that XML has nothing to do with omitted tag minimization
since it uses OMITTAG NO. I also understand that it cannot be a
goal of XML to be defined in such a way that all existing SGML is
valid XML. However, this is one case, for me, where we can gain
a large practical advantage for what seems to me to be a very minimal
addition to the spec and to implementations.
Since OMITTAG will always be NO, all I'm asking is that we define
the XML grammar so that an optional omitted tag minimization field
in an element declaration would be allowed but be ignored by an
XML processor. Note that this doesn't affect what we think will
be the great bulk of light weight read-only clients, since most of
these implementations won't read the DTD at all. So all we're
talking about are those XML tools (since SGML already works this
way) that process a DTD, and all we are asking is that they allow
(and ignore) a couple optional characters in an element declaration.
The benefit here isn't that some (probably small) number of existing
DTDs will now be valid XML DTDs without modification (though that is
a true statement), but rather that a DTD can now be written that will
work in multiple situations. It would now be possible to write a DTD
that both works with an XML processor as well as works with an SGML
tool that may use OMITTAG YES.
If we don't allow omitted tag minimization, I fear we will increase
the number of cases were people feel they must maintain two versions
of every DTD (the fact that people like to have omitted tag minimization
in their DTDs should be obvious given the fact that practically all
common DTDs out there include this information).
Can we reconsider allowing the omitted tag minimization in element
declarations in XML?