Re: [csswg-drafts] [css-syntax] Trim whitespace around declarations? (#774)

Thank you for the inset example.  I suppose there's no example where empty token sequence is absolutely necessary, in that no (other) property accepts an empty token sequence, but the inset example at least demonstrates significant inconvenience to disallowing an empty token sequence.

Regarding the initial value, css-variables-1 says

> The initial value of a custom property is an empty value; that is, nothing at all.

Combined with the fact that custom property values in effect token sequences, I had taken this to mean an empty sequence of tokens.  Possibly this understanding was influenced by the fact that an empty token sequence was not otherwise valid for custom property values at the time that I formed that understanding.

If that is a misunderstanding, then I suggest changing the spec accordingly.  (And more generally, changing the initial value is one way of resolving the problem, as mentioned previously.)

As you say, the serialization value remains another problem that would need changing.

The point about core grammar influencing adoption costs was a minor one and I don't want to spend too much space on it here, but css-syntax does not mention the terms core grammar or syntax, which is still <a href="https://drafts.csswg.org/css2/syndata.html#syntax">defined</a> by CSS2, and I believe that this definition still has a strong influence on parsing code in use today. Its promises that "This section describes a grammar (and forward-compatible parsing rules) common to any level of CSS (including CSS 2). Future updates of CSS will adhere to this core syntax, although they may add additional syntactic constraints." might also be relevant to non-renderer code that handles CSS, such as editing tools.  However, as I say, I don't consider this a major obstacle to change.


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Received on Thursday, 25 July 2019 23:11:01 UTC