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Re: [css2.1] [css3-fonts] Ambiguities relating to UNICODE-RANGE tokens

From: Zack Weinberg <zweinberg@mozilla.com>
Date: Thu, 6 Nov 2008 08:56:29 -0800
To: W3C Emailing list for WWW Style <www-style@w3.org>
Message-ID: <20081106085629.01e65683@trurl>

Bert Bos <bert@w3.org> wrote:
> On Thursday 25 September 2008 01:24, Zack Weinberg wrote:
> >
> > The regular expression defining UNICODE-RANGE in CSS2.1 is
> >
> >   U\+[0-9a-f?]{1,6}(-[0-9a-f]{1,6})?
> >
> > Core syntax issue 1 (editorial, one hopes): The initial U is in
> > upper case. All other core lexical productions are written entirely
> > in lower case.
> 
> The U is uppercase only because that is how it usually written, e.g., 
> U+0048 instead of u+0048; not because the lowercase is invalid. If
> that causes confusion, I'm happy to change the "U" to a "u" in the
> grammar. It is indeed purely editorial.

I would prefer that it be changed.  Yes, these are usually written with
the U in upper case, but if one is close-reading the spec in order to
implement it, it's nice not to have to worry about this maybe being
special.

> It didn't seem worth it to try and write a pattern that matches only 
> those UNICODE_RANGE tokens that make sense. It may be possible, but
> the pattern would certainly be quite unreadable. So it was left to
> the text to explain that certain UNICODE_RANGE tokens are
> meaningless. That text was then left out of CSS 2.1, because
> UNICODE_RANGE is not used there.
> 
> How to handle those well-formed but meaningless tokens will indeed
> have to be explained in css3-fonts.
> 
> So I agree: there is something to do for css3-fonts[1], but nothing
> for CSSĀ 2.1.

Thanks for the clarification.

> > There is also a question of what text is produced by a CSSOM query
> > for the value of an arbitrary unicode-range: descriptor.  I
> > recommend that implementations be allowed, but not required, to
> > produce a simplified representation of the range instead of the
> > original text. Continuing with the example of
> 
> I have no preference. There is a section on normalization in the
> CSSOM and such a text could probably be added there. See
> http://dev.w3.org/csswg/cssom/#parsing

Sounds good to me.

zw
Received on Thursday, 6 November 2008 16:57:53 GMT

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