Re: prefer-language tag

[Harald Tveit Alvestrand <Harald.Alvestrand@maxware.no>]

The subject of matching a client request to a set of language tags
was extensively (and exhaustingly!) discussed in the context of HTTP.
The language arrived at there (RFC 2068 section 14.4) was:

                ....... A language-range matches a language-tag if
   it exactly equals the tag, or if it exactly equals a prefix of the
   tag such that the first tag character following the prefix is "-".
   The special range "*", if present in the Accept-Language field,
   matches every tag not matched by any other range present in the
   Accept-Language field.

     Note: This use of a prefix matching rule does not imply that
     language tags are assigned to languages in such a way that it is
     always true that if a user understands a language with a certain
     tag, then this user will also understand all languages with tags
     for which this tag is a prefix. The prefix rule simply allows the
     use of prefix tags if this is the case.


Note the two clarifications:

- A language-range is NOT a language-tag
- The matching rule is ONLY "user is allowed to ask for this",
  NOT "this request must always make sense".

It's one of the things that should go into RFC 1766 when it's updated;
the term "does not sufficiently cover" is perfectly accurate.

                      Harald A

NOTE: New Email address: Harald.Alvestrand@maxware.no
I am working for Maxware (www.maxware.no) as of Dec 1, 1997