[css-grid] Should <custom-ident> in grid-template-rows/grid-template-columns exclude "span"?

Hi www-style,

(This is about a related but slightly more subtle issue than my previous
email[0]).

Question: Should "span" be accepted as a valid <custom-ident> value, in
the <line-names> list for the grid-template-columns and
grid-template-rows properties?

The keyword "span" does *not* appear in these properties' value
definition[1], so it would seem that they should accept it. (based on
the definition of <custom-ident>)

HOWEVER: The keyword "span" *does* appear in the value definition for a
*different* group of properties -- grid-row-start, grid-column-start,
grid-row-end, and grid-column-end[2] -- and those properties *also* take
a <custom-ident>, which can correspond to the same <custom-ident> used
in grid-template-rows/grid-template-columns. (Both of them can refer to
named lines.)

So if we do allow 'span' as a <custom-ident> for
grid-template-rows/grid-template-columns, it'll just be guaranteed to
fail to match against any corresponding <custom-ident> in
"grid-row-start" & friends (since it won't be a valid <custom-ident> for
those properties).

Maybe that's OK? (I tend to think it's OK; I'm just sanity-checking my
understanding, while reviewing a patch to implement this parsing in
Mozilla.)

Thanks,
~Daniel

[0] http://lists.w3.org/Archives/Public/www-style/2014Feb/0734.html
[1] http://dev.w3.org/csswg/css-grid/#track-sizing
[2] http://dev.w3.org/csswg/css-grid/#line-placement

Received on Wednesday, 26 February 2014 02:07:25 UTC