- From: Simon Sapin <simon.sapin@exyr.org>
- Date: Mon, 23 Mar 2015 17:19:08 +0100
- To: www-style list <www-style@w3.org>
The grammar currently is:
> <media-condition> = <media-not> | <media-and> | <media-or> | <media-in-parens>
> <media-not> = not <media-in-parens>
> <media-and> = <media-in-parens> [ and <media-in-parens> ]+
> <media-or> = <media-in-parens> [ or <media-in-parens> ]+
When parsing <media-condition>, deciding which of the alternatives
should be taken may require looking ahead by an unbounded amount.
To avoid this, it could be rewritten as:
<media-condition> = <media-not>
| <media-in-parens> [ <media-and>* | <media-or>* ]
<media-not> = not <media-in-parens>
<media-and> = and <media-in-parens>
<media-or> = or <media-in-parens>
Unfortunately that makes more awkward the definitions that follow
> Each of the major terms of <media-condition> is associated with a
> boolean result, as follows:
Note that we made a similar change to the @page grammar for this reason:
https://lists.w3.org/Archives/Public/www-style/2012Apr/0620.html
(Although the @page one is even more awkward, since we had to use
recursion instead of repetition.)
--
Simon Sapin
Received on Monday, 23 March 2015 16:19:31 UTC