> From: Dave Singer [mailto:singer@xxxxxxxxx]
>This is similar to the reason why the language code comes before thecountry>code. If we had the order CH-fr, then we could end up mixing Frenchand>German in the same page, because we would fall back (for one of thedata>sources) from CH-fr to CH, which could be German.
It has to be application-specific which fallback happens. If the user says he's swiss french, and the the content has alternative offers for swiss german or french french, which do you present? If the content actually differs for legal or geographic reasons ('the legal representative in your country is', 'for copyright reasons this edition differs in material ways from other countries'), then the correct country but wrong language is the best answer. If the desire is simply for maximum intelligibility, then the reverse is true.
But that is a level of decision making that goes well beyond any algorithm that simply uses truncation of tags, which is the only case in which the ordering of sub-tags matters.
Sorry, I should have gone on to conclude: the important aspect of sub-tags is that their nature and purpose be identifiable and explained (e.g. that this is a country code), and that we retain compatibility with previous specifications. This tagging uses order (and size) of sub-tags rather than explicit labels to say what something is, and we're stuck with that. I don't believe that simple truncation is a necessarily useful operation in all circumstances, and it probably should not be in the spec. at all. For example, I'd say that we should retain the 3066 ordering of language-country and therefore script, if needed, comes later. However, my typesetting subsystem doesn't care a jot about language or country, it just needs to find the script code ('can I render this script'?).
This spec. should unambiguously allow me to extract the language, country, script etc., should say under what circumstances two sub-tags of any type match, state the obvious that two tags exactly match if they have the same sub-tags and they all match, that partial perfect matches (of tags with differing numbers of sub-tags) are possible and may be applicable, and that the use of imperfect matches (in which not all sub-tags match) has to be application-specific. Examples of why on the latter would be helpful.
--
David Singer
Apple Computer/QuickTime
_______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf