W3C home > Mailing lists > Public > public-css-archive@w3.org > July 2018

[csswg-drafts] [css-grid] grid-line custom identifier auto?

From: Eric Willigers via GitHub <sysbot+gh@w3.org>
Date: Mon, 02 Jul 2018 07:41:04 +0000
To: public-css-archive@w3.org
Message-ID: <issues.opened-337403038-1530517263-sysbot+gh@w3.org>
ewilligers has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-grid] grid-line custom identifier auto? ==
Blink and WebKit reject grid-row-end `1 auto`.
Edge and Firefox accept grid-row-end `1 auto` and serialize it as `1 auto`.

Blink and WebKit reject grid-row-end values `span 1 auto`, `span auto 1` and `1 auto span`.
Edge and Firefox accept these and serialize all of them as `span 1 auto`.

Testing with uppercase makes it clear that `span` is being accepted as a keyword and `auto` is being accepted as a custom identifier:
http://jsfiddle.net/ericwilligers/meya2q7d/

All browsers reject the following:
`auto 1`
`span span 1`, `span 1 span` and `1 span span`
`1 span auto`, `auto 1 span` and `auto span 1`



The relevant grammar for `<grid-line>` is
```
<grid-line> =
  auto |
  <custom-ident> |
  [ <integer> && <custom-ident>? ] |
  [ span && [ <integer> || <custom-ident> ] ]
```

Are `auto` or `span` permitted as a `<custom-ident>`?

The [custom-ident spec](https://drafts.csswg.org/css-values-4/#identifier-value) may be relevant:

> Note: When designing grammars with `<custom-ident>`, the `<custom-ident>` should always be "positionally unambiguous", so that it’s impossible to conflict with any keyword values in the property.

I don't see a reading of the spec where `span 1 auto` would be permissible but not `span 1 span`.


Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/2856 using your GitHub account
Received on Monday, 2 July 2018 07:41:07 UTC

This archive was generated by hypermail 2.3.1 : Monday, 2 July 2018 07:41:07 UTC