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RE: [CSS21] 12.5 Lists: numbering undefined, implementations differ

From: Arron Eicholz <Arron.Eicholz@microsoft.com>
Date: Wed, 16 Mar 2011 23:27:31 +0000
To: Peter Moulder <peter.moulder@monash.edu>
CC: "www-style@w3.org" <www-style@w3.org>
Message-ID: <07349ECFC3608F48BC3B10459913E70B12D157FC@TK5EX14MBXC132.redmond.corp.microsoft.com>
On Tuesday, September 07, 2010 2:28 PM Peter Moulder
> By "numbering" here, I mean the number as distinct from what string to
> display for a given number.
> As far as I've seen, there's no text saying what number to give for a given list-
> item.  The closest I've seen is an example of an <li> list in an HTML document;
> but note that that's an HTML list, whose numbering is [more or less] defined
> by the HTML spec, and so doesn't tell us much about how <span
> style="display:list-item"> should be numbered, or how list-items in generic
> XML documents should be numbered (when styled by CSS).
> I append a document with a few tests, to see what existing user agents are
> doing.
> Of the four user agents I tested, no two do the same thing.
> In the implementations I looked at, it seems that in an HTML document, <ol>
> is special for display:list-item elements even other than <li>; and numbering
> of list-items that are descendents of an <ol> element had less variation in
> behaviour.
> (Looking at WebCore source code, it seems that the test is ol or ul.
> A reasonable starting point for the relevant code in WebKit would be
> RenderListItem::calcValue.)
> <ol> loses its magic in generic XML documents in each of the user agents
> whose generic XML behaviour I tested.
> Relevant to discussion would be http://www.w3.org/TR/css3-lists (search for
> counter; though the main point is that display:list-item implicitly increments a
> counter called list-item), and its dependency http://www.w3.org/TR/css3-
> content/ for most of the information regarding numbering.  Whether
> intentional or not, the numbering appears to be order within document tree,
> as modified by pseudo-elements such as :before and :after (by my reading,
> though it isn't very clear about this), and as modified by display:none, but not
> modified by run-in or 'caption-side' or anonymous block box processing; and
> as modified by the suppression of children of 'table-column' boxes and
> suppression of non-'table-column' children of 'table-column-group', but not
> modified by the rest of anonymous table object creation rules.  (Anonymous
> block processing and anonymous table object creation don't affect order of
> boxes/elements, but would be relevant to counter
> scope.)
> Note that both css3-lists and css3-content are at working-draft status.
> Possibly the resolution to this issue would be to note explicitly that CSS2.1
> does not define the number assigned to a given list-item, and that this is
> expected to be defined by a future level of CSS, probably making some
> mention of css3-lists (already in refs.html as #ref-CSS3LIST).
> I attach the HTML version of the tests, while the corresponding XML version
> (and its associated stylesheets, and the HTML version for good measure) is at
> http://bowman.infotech.monash.edu.au/~pmoulder/html-tests/list-item-
> numbering/
> N.B. One of the tests caused a segfault in a WebKit-based browser; if that
> happens then comment out the :before rule in the stylesheet.

Thank you for your feedback. The CSSWG has addressed your concerns in the upcoming publication of the CSS 2.1 specification[1]. 

The CSSWG resolved to add a note making the exact numbering undefined for CSS 2.1.

We hope this closes your issue.

Please respond before 18 March, 2011 if you do not accept the current resolution.

[1] http://w3.org/TR/CSS
Received on Wednesday, 16 March 2011 23:28:04 UTC

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