W3C home > Mailing lists > Public > www-style@w3.org > November 2007

Re: [CSS21] Case-insensitivity not defined

From: Martin Duerst <duerst@it.aoyama.ac.jp>
Date: Mon, 19 Nov 2007 08:24:24 +0900
Message-Id: <>
To: Addison Phillips <addison@yahoo-inc.com>
Cc: fantasai <fantasai.lists@inkedblade.net>, www-international@w3.org, www-style@w3.org

At 04:59 07/11/19, Addison Phillips wrote:

>>   For XML, that's the other way round. The only thing that
>>   CSS can do here reasonably is to follow whatever the
>>   target language specifies, both for the basic question of
>>   case-sensitive or not as well as for the details regarding
>>   non-ASCII characters, if applicable. 
>Unfortunately, HTML's definition of case-insensitive---the entire definition---is:
>The value is case-insensitive (i.e., user agents interpret "a" and "A" as the same).
>(see: http://www.w3.org/TR/html4/types.html#h-6.1)
>... which is insufficient to know what qualifies as a conforming implementation.

Very much so. But it's not the job of CSS to fix this.

[I wrote:]

>> - Identifiers within CSS. These include cases such as
>>   namespace prefixes and counter names inside CSS.
>>   Ideally, these should just work case-sensitive; I don't
>>   think it's asking too much from stylesheet writers to
>>   use the same case for all occurrences of a specific
>>   counter name. If that's not possible for legacy reasons
>>   (e.g. stylesheets that indeed use counter names and
>>   friends with haphazard casing), then something like
>>   'case-insensitive for US-ASCII, case sensitive for
>>   the rest', even though it sounds terribly ugly, may
>>   be the best solution.
>I agree. But since CSS currently does NOT make these case-sensitive, we need to specify what does happen.
>The problem here is that many implementers are likely to call extant case-insensitive string comparison functions (or perform a locale-sensitive operation, such as tolower) rather than implementing a specific comparison or taking care to avoid the locale problem.
>So I guess, in summary, what I'm suggesting is either:
>1. Change case sensitivity to remove the need for any non-ASCII case insensitive comparisons and then specify ASCII case insensitivity for CSS keywords and the like.
>2. Change the case sensitivity to reference Unicode case folding (section 3.13, IIRC).
>If we specify ASCII-only case-insensitivity, it should be abundantly clear in the text that this is not an internationalization oversight but a deliberate design decision.

I agree.

Regards,    Martin.

#-#-#  Martin J. Du"rst, Assoc. Professor, Aoyama Gakuin University
#-#-#  http://www.sw.it.aoyama.ac.jp       mailto:duerst@it.aoyama.ac.jp     
Received on Sunday, 18 November 2007 23:51:02 UTC

This archive was generated by hypermail 2.3.1 : Monday, 2 May 2016 14:27:31 UTC