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Re: [css-syntax] Ready for wide review, FPWD request coming soon

From: Zack Weinberg <zackw@panix.com>
Date: Sat, 18 May 2013 21:27:11 -0400
Message-ID: <51982A6F.8020306@panix.com>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
CC: www-style list <www-style@w3.org>
On 2013-05-17 4:16 PM, Tab Atkins Jr. wrote:
> On Fri, May 17, 2013 at 11:12 AM, Zack Weinberg <zackw@panix.com> wrote:
>> * Regarding recursive-descent-style tokenization and removal of
>>    pushback, you were skeptical that this would be easier to read.
>>    Would you be interested in me attempting to rewrite section 4 with
>>    those changes, to see how it goes?  It would be pretty major so I
>>    don't want to do it if you're not at least curious whether it would
>>    be better.
>
> A small section would suffice.  Could you just try rewriting the
> number/percentage/dimension parsing?  That's probably the most complex
> set of interlocking states.

OK, I'll try that.

>> * throughout: Unlike other Unicode character names, U+FFFD REPLACEMENT
>>    CHARACTER should *not* be followed by the literal character in
>>    parens (�).
>
> Why?

Um, I have this vague memory that the Unicode standard somewhere says 
literal REPLACEMENT CHARACTER isn't supposed to appear in original 
documents -- it's only for when conversion processes throw up their 
hands -- but I can't find the text I'm remembering and it's possible 
there never was any such statement.  Anyway it's not that important.

>> * 4. Unicode-range tokens may need a "valid" flag.  I need to
>>    cross-check the code in Gecko against the algorithm in this spec
>>    carefully, but the definition of UNICODE-RANGE in CSS2.1 included
>>    several forms that were semantically invalid.
>
> The parser in Syntax ended up only accepting valid unicode ranges
> (except that it does, technically, allow for ranges where the min is
> higher than the max).  This is more restrictive than CSS 2.1, but it
> only fails to cover things that were invalid in the first place.

I will pay careful attention to this section when I go back through.

zw
Received on Sunday, 19 May 2013 01:27:40 UTC

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