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Re: [css-images] Syntax for image() incorrect?

From: Sebastian Zartner <sebastianzartner@gmail.com>
Date: Thu, 3 Mar 2016 23:04:33 +0100
Message-ID: <CAERejNZ_hA+aVE8j-_3Q3no6FQU3q+p1vEwbRwMy9ehNpxVR4w@mail.gmail.com>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
Cc: www-style list <www-style@w3.org>
On 3 March 2016 at 20:57, Tab Atkins Jr. <jackalmage@gmail.com> wrote:
> On Thu, Mar 3, 2016 at 5:37 AM, Sebastian Zartner
> <sebastianzartner@gmail.com> wrote:
>> The description for the image() function says that it allows to use a
>> solid color as an image.
>>
>> Though its syntax is defined as
>>
>>     image( [ [ <image> | <string> ]? , <color>? ]! )
>>
>> meaning that colors are only allowed as fallback values.
>
> How are you getting this?  The syntax marks both parts as optional,
> and just requires that you specify one of them.  So image(blue) is
> valid per that grammar.
>
>> Furthermore, the syntax for the image() function suggests that the
>> comma stands for its own and is not influenced by the question mark
>> multiplier after <color>.
>
> Correct, but https://drafts.csswg.org/css-values/#comb-comma clarifies
> how commas work in CSS grammars - they're automatically required to be
> omitted unless they're actually separating things.

Ah, I didn't know that. So then it's obviously valid.

Regarding my second point about extending <image> to accept <color>
values, I saw that you had the same idea some years ago.[1]
It looks like fantasai was reluctant to this idea but the thread
didn't come to a conclusion and as far as I can see this is also not
mentioned in any WG minutes. So, maybe this topic should be revived?

Sebastian

[1] https://lists.w3.org/Archives/Public/www-style/2010Nov/0380.html
Received on Thursday, 3 March 2016 22:05:22 UTC

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