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Re: proposed li:marker pseudo-class

From: Philip TAYLOR <Philip-and-LeKhanh@Royal-Tunbridge-Wells.Org>
Date: Sat, 05 Apr 2008 08:31:26 +0100
Message-ID: <47F72ACE.8050408@Royal-Tunbridge-Wells.Org>
To: Ernest Cline <ernestcline@mindspring.com>
CC: www-html@w3.org



Ernest Cline wrote:

> Let me quote from the 1993 HTML draft:

> "A list is a sequence of paragraphs, each of which may be preceded by a special mark or sequence number."

Fine, many thanks for the reference.  For interested parties,
I believe Ernest is citing from

	http://www.w3.org/MarkUp/draft-ietf-iiir-html-01.txt

which certainly (to my mind) confirms Ernest's beliefs.

> That's not to say that a semantic meaning couldn't be grafted onto the two, 
> but I've never heard anyone give a compelling reason why a browser should 
 > be free to render the LI's of a UL in any order it wishes,

Well, I might want to argue that it /should/ have
that freedom, but equally I can see few reasons why it might
want to use that freedom if given it, although an intelligent
rendering engine might want to make use of such freedom to improve
the aesthetics of the displayed list (e.g., to avoid a
single list item from being visually split at a line turn).
But this is equally true of any "sequence" of entities where
the rendering engine is not constrained as to the order of
presentation, not just unordered lists.

However, I suspect that this freedom is a step too far :
in general, a rendering engine should present the
author's material in the same order that the author
presents it in the source document, unless (a)
the author (or his/her agent) uses CSS to re-order
things, and/or (b) we postulate a new property
whereby an author may specify that, at a given
level of granularity, the rendering engine is free
to adjust the order of presentation in order to
satisfy some other constraint.  For example,
considering paged media, it may be better to
present "Figure 4" before "Figure 3" if "Figure
4" fits on the current page whilst "Figure 3"
does not.

> and given the 
 > possibility that the text may refer to the 3rd item of a bulleted list,
 > I have a compelling reason why it shouldn't.

I can imagine an author referring to the third such item;
I can't, in all honesty, imagine him/her referring to
the 23rd such item, or the 157th, or so on, since beyond
10 or so items it would be very hard (with only bullets
for guidance) to unambiguously identify a particular
item other than by its context/contents.

But to clarify my own thinking (and teaching) on the
difference between the two (<UL> and <OL>, that is) :
I believe that the former is intended for applications
where the reader (a human) is not intended to ascribe
any significance to the order of presentation, whilst
I believe that the latter is intended for use where
the order is vital to the understanding.  The examples
that I usually give when teaching are :

	<UL> : the ingredients for making a cake
	<OL> : the sequence of steps necessary
		to make the cake

Philip TAYLOR
Received on Saturday, 5 April 2008 07:31:58 GMT

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