W3C home > Mailing lists > Public > www-style@w3.org > April 2010

Re: Splitting 'display'

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Wed, 21 Apr 2010 08:49:42 -0700
Message-ID: <p2ydd0fbad1004210849i674ca2ccu1af8144a6ed79d60@mail.gmail.com>
To: Mikko Rantalainen <mikko.rantalainen@peda.net>
Cc: www-style list <www-style@w3.org>
On Wed, Apr 21, 2010 at 12:12 AM, Mikko Rantalainen
<mikko.rantalainen@peda.net> wrote:
> Tab Atkins Jr. wrote:
>> On Fri, Apr 16, 2010 at 7:34 PM, Andrew Fedoniouk
>> <news@terrainformatica.com> wrote:
>>> Tab, are you trying to re-introduce display-model and display-role from
>>> here: http://www.w3.org/TR/2002/WD-css3-box-20021024/#L706
>>> ?
>>
>> Yes, precisely.  That's the draft that I took some text from, actually.
>
> That would have been nice to point out in the beginning. Could you
> elaborate about the important differences between your latest version
> and the old working draft?

I did mention it in the first paragraph of my original message, though
I didn't specify exactly which document I took it from.  Mea culpa if
that was important info.

There are three areas of difference between my draft and the older draft:

1. Some names have been changed
2. All corner cases are specified (the older draft forgot to address a
few places)
3. A slightly different mapping between some of the single-keywords
forms and the double-keyword forms.  I don't think the differences
here are significant.

> I agree with the idea of splitting the 'display' property in parent and
> child parts.
>
> Why you did not use 'display-model' and 'display-role' as previously
> specified? Do you believe that 'display-inside' and 'display-outside'
> are more clear?

Yes, it took me some time before I finally got it sorted out in my
head precisely what -model and -role *meant*, and stopped confusing
the two.  Maybe I'm abnormal.  ^_^  I think that -inside and -outside
describe well what the values apply to.  I'm still open to other names


> I agree with your reasoning about list-item and the I think that it
> requires something pretty special. I'm afraid that for backwards
> compatibility and special side-effects required for current definition
> of 'display: list-item', the only logical choice is a third display
> property. I don't know if it should be called 'display-extras' or
> 'display-side-effects' or 'display-magic' or 'display-compatibility' but
> it would make following
>        display: list-item;
> a short hand for
>        display-outside: block;
>        display-inside: inline;
>        display-extras: list-item; /* ::marker and counter magic */

Well, display-inside is 'block' for list-item, but otherwise yes.


> I'd suggest using the name 'display-compatibility' because hopefully the
> list-item is the only feature ever needing this hack. Using the word
> 'compatibility' in the property name should be make it obvious that new
> features should not use this property. On the other hand, there may not
> ever be a time when an UA vendor could stop supporting 'display:
> list-item' (in favor of newer features). I think the word
> 'compatibility' should be used only if the feature would be deprecated
> in the future.

There is no reason whatsoever to deprecate display:list-item.  The
only thing wrong with it is that it's exactly like block, but with
magic, so anytime we have to say something about display:block right
now, we have to remember to include list-item.  If we can prevent that
by separating out the magic, then everything's fine.  Keeping
display:list-item as a shorthand is perfectly useful and fine for
content to continue using.


> In addition, I agree with Andrew Fedoniouk that splitting the 'display'
> property does not change anything in itself. However, I still believe
> that this change would be beneficial in the long run, because it would
> simplify defining new features as Tab Atkins Jr. reasoned. In addition,
> it would make explicit to UA vendors that the engine must be able to use
> separate algorithms for the the inside and outside of any element.

That's not *quite* accurate.  Splitting the display property *would*
have an effect right now, namely that of enabling list-items and
table-cells to be tables themselves.  This is very minor right now,
though.  The real effect comes in later, when we properly introduce
the template and flexbox display types.  These really *are* useful to
be applied directly to a list-item or table-cell.  This also prevents
us from being forced to introduce inline-template and inline-flexbox
directly, which is just silly imo.


> Why was the previous split (display-model/display-role) abandoned? It
> does not exists in latest draft as far as I know.

Not sure.

~TJ
Received on Wednesday, 21 April 2010 16:16:46 GMT

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