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Re: [CSS21] 17.4: properties on outer & inner table boxes

From: Peter Moulder <peter.moulder@monash.edu>
Date: Sun, 07 Nov 2010 08:14:56 +1100
To: www-style@w3.org
Message-id: <20101106211456.GA3649@bowman.infotech.monash.edu.au>
On Sat, Nov 06, 2010 at 09:37:05PM +0100, Anton Prowse wrote:

> I don't think this is an issue since, as I understand it, the table
> box doesn't have a 'display' property.  The value of the 'display'
> property of an element determines (sometimes in conjunction with
> other information) the types of boxes that the element generates.
> The boxes themselves don't necessarily correspond exactly to the
> values of the 'display' property.  A table box is outwardly
> block-level and inwardly table, for example.
> 
> When the spec sloppily refers to blocks, inline blocks, inline
> tables, tables, list items etc in a context where it's really
> talking about boxes, the only sensible assumption is that it's
> referring to the principal box of the element of that type, so the
> issue above doesn't arise.  Of course, principal box is defined in
> generality either, but is defined enough to exist for table and
> inline table elements.
> 
> I guess what I'm saying is that this area is sloppy, but I don't
> think there's any unique difficulty with the case that you describe.
> Of course, I'd like to see the spec fixed in full generality....

I've no objection to taking that approach (it might work well for the
principal box of a display:list-item element, for example, and I agree that
one might question how meaningful it would be to describe the inner table
box as having display:table as I suggested above), though there would need
to be some changes to the text if we were to adopt it.  For example, 17.4
para 3 currently starts with "The outer table box is a 'block' box if the
table is block-level, and an 'inline-block' box if the table is
inline-level", even though it's never generated by either a display:block
element or display:inline-block element.

Also, 9.2 isn't really consistent with the above approach at present: it
talks of "A box's type" (type singular), which I would tend to see as more
consistent with "type" referring to display value than as the combination
of whether it's block-level or inline-level and whether it's a block
container or ...  (Though in any case, I have always been uneasy with
the existing text "a box's type" when nothing in the text says what a box's
type is.  It turns out that this sentence isn't needed normatively, but I'd
still like to have this sentence changed so that readers like me don't
spend time trying to work out what the sentence means.)

I'm also inclined to think that the talk of "..., list items etc. in a
context where it's really talking about boxes" is something of an obstacle.
Though maybe we could get around it with a single sentence in 9.2
explaining this, ending with "except that the outer table box is ..." or
similar.

pjrm.
Received on Saturday, 6 November 2010 21:15:28 GMT

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