Re: Adding new tags (was: Redefining...)

Bert Bos (bert@let.rug.nl)
Mon, 13 Jun 1994 13:58:53 +0200 (METDST)


Message-Id: <9406131158.AA06048@freya.let.rug.nl>
From: Bert Bos <bert@let.rug.nl>
Subject: Re: Adding new tags (was: Redefining...)
To: rskm@VNET.IBM.COM
Date: Mon, 13 Jun 1994 13:58:53 +0200 (METDST)
Cc: www-html@www0.cern.ch
In-Reply-To: <0hyBLhk91JbQNAZbo4@rchland.ibm.com> from "Robert Kemmetmueller" at Jun 10, 94 11:08:42 pm

[Robert Kemmetmueller:]
 |[Bert Bos:]
 |> `Render' is not used to introduce new tags, rather it is used to
 |> define styles for elements already introduced in the document subset
 |
 |8-|   [``dazed newbie'' expression]
 |
 |CAN I, or can I NOT, do the following?
 |
 |    <render tag="COMMENT" style="i">
 |    <render tag="FUNCTION" style="b,u">
 |
 |    <pre><code>
 |      <COMMENT>/* foo.c, written by me */</COMMENT>
 |
 |      int <FUNCTION>main</FUNCTION>(int argc, char *argv[])
 |      {
 |          return 0; <COMMENT>/* all done! */</COMMENT>
 |      }
 |    </code></pre>
 |
 |I kind of thought that was the whole point of the <RENDER> thing when I
 |saw it.  Am I out to lunch, or is there just some "tag / element"
 |distinction I missed completely when reading your quote, above?

Yes, this is what RENDER is for. And most (future) HTML3.0 browsers
will do the right thing here.

However, strictly speaking, this is only part of the definition of
COMMENT and FUNCTION, viz., the *semantic* part. The RENDER tag
doesn't give the *syntax*. It doesn't say, e.g., how the elements may
be nested.

HTML relies on SGML to specify syntax, which means that somewhere in
the first part of the document there must be an `<!ELEMENT'
declaration for each tag that is used in the document, including this
COMMENT and FUNCTION.

I won't repeat the SGML declaration here, it has appeared on this
mailing list several times already and when Dave Raggett finishes the
documentation for HTML 3.0 it will all be explained much better that I
can do here.

Now the remaining question is: what will/should browsers do when they
encounter a RENDER tag for an undeclared element? A good guess might
be to simply assume the syntax is the same as for the EM tag.


Bert
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