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RE: Pseudo-classes and -elements

From: Chris Wilson (PSD) <cwilso@microsoft.com>
Date: Tue, 9 Apr 1996 11:47:57 -0700
Message-Id: <c=US%a=_%p=msft%l=RED-76-MSG-960409184757Z-3286@red-07-imc.itg.microsoft.com>
To: "'rieger@bse.de'" <rieger@bse.de>, "'Hakon Lie'" <howcome@w3.org>
Cc: "'www-style@www10.w3.org'" <www-style@www10.w3.org>
I would like to put in a strong vote that we NOT change the syntax in
such a way now.  As a vendor working on a CSS implementation, if we keep
changing the basic syntax, we'll never be finished.

Although it did take me a while to visualize how different
pseudo-classes and pseudo-elements are, I believe they are similar in
concept enough to use the same separator - they're a subset of the given
selector.  Even now that I understand how different they are, I still
like the syntax to unify them, and it's so blindingly easy to parse them
out that I don't see a compelling reason to separate them now.

At the very least, we should keep one of the pseudo-* separators as ':'
to reduce upgrade woes.

The "immediate predecessor" idea Hakon brings up would seem more
intuitive to me using '+'.

	-Chris
Chris Wilson
cwilso@microsoft.com
-[-

>----------
>From: 	Hakon Lie[SMTP:howcome@w3.org]
>Sent: 	Tuesday, April 09, 1996 8:42 AM
>To: 	rieger@bse.de
>Cc: 	www-style@www10.w3.org
>Subject: 	Pseudo-classes and -elements
>
>Wolfgang Rieger writes:
>
> > Further, there is a semantic distinction between pseudo-classes and
> > pseudo-elements (pseudo-classes are more like attributes while 
> > pseudo-elements are more like elements). IMHO there should be
> > a formal distinction between the two constructs. Otherwise (as I
> > have noted in recent postings) pseudo-classes and pseudo-elements
> > will be confused.
>
>Good point. Let's find two characters -- here are some suggestions:
>
>Pseudo-elements:
>
>  H1/first-line
>  H1/first-letter
>
>  H1+first-letter
>  H1+first-line
>
>  H1~first-letter   /* mnemonic: tilde ressembles an 's' as in "H1's
>first-letter" */
>  H1~first-line
>
>Pseudo-classes:
>
>  A+visited
>  A+active
>  A+link
>
>  A!visited
>  A!active
>  A!link
>
>  A?visited
>  A?active
>  A?link
>
>What do people think?
>
> > I'm currently thinking about how to interpret style sheets for
> > arbitrary SGML documents with arbitrary DTDs. For this purpose, I
> > think it necessary to allow selection of elements via attribute 
> > values.
>
>Yes this is scheduled for CSS2 (or whatever it will be called):
>
> H1[class=funk] { .. }
> A [HREF]       { .. }
>
>
> > if you change the meaning of the colon-notation "A : B" from "B is
> > pseudo-element in A" to "B is child of A" (i.e. direct descendant), 
> > you are compatible with existing implementations and have a 
> > consistent extension of the selector syntax.
>
>Another very good point. A slightly different angle of attack: now
>that the colon is freed up, how can we make best use of it? HTML
>documents are rather flat, and we may have more need to look for
>predecessor relationships (i.e. immediate sibling) than parent-child
>relationships. So:
>
>  H1 : P { .. } 
>
>could address P elements immediately following H1 elements.
>
>For SGML in general, this may not hold?
>
>Regards,
>
>-h&kon
>
>Hakon W Lie, W3C/INRIA, Sophia-Antipolis, France
>http://www.w3.org/people/howcome  howcome@w3.org
>
>
Received on Tuesday, 9 April 1996 14:47:33 GMT

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