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Re: [csswg-drafts] Font-family name matching requires full Unicode case comparison (#3675)

From: Dominik Röttsches via GitHub <sysbot+gh@w3.org>
Date: Tue, 26 Feb 2019 09:25:47 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-467363173-1551173146-sysbot+gh@w3.org>
> This is the only place in WebKit that requires a full Unicode case matching. 

Can you specify in more detail what do you mean by full Unicode case matching here? Do you mean case-sensitive matching? I understand the current spec to mean: Perform "Default Caseless Matching" from https://www.unicode.org/versions/Unicode9.0.0/ch03.pdf section 3.13, with emphasis on doing that without normalization and without language specifc tailorings. This would be only the comparison mentioned in the Unicode spec as D144:

> D144 A string X is a caseless match for a string Y if and only if:
> toCasefold(X) = toCasefold(Y)

Implementation wise, I believe this would be http://icu-project.org/apiref/icu4c/classicu_1_1UnicodeString.html#a0924f873180947aab38b7380da638533  with `U_FOLD_CASE_EXCLUDE_SPECIAL_I`.

I think the spec already describes that this flag should be set accordingly, as tailorings are excluded from the matching algorithm.

What performance benefits do you see from only performing casefolding for the ASCII range?

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Received on Tuesday, 26 February 2019 09:25:49 UTC

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