- From: Robert Burns <rob@robburns.com>
- Date: Thu, 2 Aug 2007 02:29:28 -0500
- To: Maciej Stachowiak <mjs@apple.com>
- Cc: Sander Tekelenburg <st@isoc.nl>, public-html@w3.org
On Aug 2, 2007, at 2:21 AM, Maciej Stachowiak wrote: > > > On Aug 1, 2007, at 8:53 PM, Robert Burns wrote: > >> >> I'm not really sure what you're asking. But what I'm trying to say >> is that fully expressing a language using @lang or @xml:lang >> provides all of the information required to deduce the >> directionality. So to take just one of the examples I gave above: >> >> lang='iw-LATN'=> dir='LTR' >> >> In that case the @dir attribute is technically redundant. I'm not >> saying that UAs work that way now. Rather I'm saying that by >> specifying language (including the specification of unconventional >> scripts), all the information is there to determine >> directionality. For some languages what demarcates the >> unconventional script may be up for debate and can even be a >> political football. If the web was around a century ago or so when >> Turkey was imposing a change from Arabic to Latin script, it would >> be difficult to say which was the conventional script. It would >> probably require specifying precisely which one was in use either >> way (if the government permits it). >> >> Again, though having @dir as a separate attribute saves UAs from >> the need to process language codes to determine directionality. It >> also is more flexible in the sense that an author can specify only >> @dir and leave @lang unspecified. Or specify @dir and @lang but >> provide only the primary language code with no script code. Doe >> that answer your question? > > HTML4 says that "User agents must not use the lang attribute to > determine text directionality", and current user agents respect > this. It is highly likely that content depends on lang and dir > being treated separately. So reversing this requirement in HTML5 > would likely not be compatible with existing content. > > Note that dir only affects directionally neutral characters, not > characters from scripts with inherent directionality, so there are > valid reasons to write text in various languages that uses either > dir value. I never suggested anywhere that we should require UAs to determine directionality from the @lang attribute. Take care, Rob
Received on Thursday, 2 August 2007 07:30:27 UTC