Revised I-D: draft-alvestrand-content-language-03

Bruce Lilly
Fri, 15 Feb 2002 12:47:44 -0500

Harald Tveit Alvestrand wrote:
> Internet-drafts,
> please publish this.
> ietf-languages and Bruce Lilly: Please review.
> The main change is in the ABNF of the headers; all are now specified in RFC
> 2282 ABNF, and use the "obs-" formalism from RFC 2822 to specify accept and
> generate grammars.
> Thanks!
>               Harald

[that's 2234 ABNF, which is correctly referenced in the document]

It looks good, but might benefit from some clarification w.r.t.
the obs- forms:

1. It should be pointed out that only the 2234 ABNF version
   (not the 822 version) should be used for generation of new
   headers.  Ambiguity arises because the last paragraph in
   section 2 refers to "the Content-Language syntax", whereas
   both the 822 EBNF and 2234 ABNF definitions are labeled
   "Content-Language".  Suggestion: LHS of the 822 definition
   could be "822-content-language". LHS of the 2234
   definition could be "content-language", and the text of
   the last paragraph could refer to the latter.  The same
   consideration applies to section 3 and Accept-Language.

2. The obs-content-language header definition uses the same
   Language-List definition as the not obs- version.  2822
   generally provides an obs- version of list constructs for
   backward compatibility of parsing headers generated under
   the more liberal 822 list rules (viz. empty list elements).
   If it is certain that no Content-Language headers have ever
   been generated containing empty list elements (e.g.
   ",en,,fr,"), this is not a problem. Otherwise, in the
   spirit of 2822:
   obs-language-list = Language-List
                     / 1*([Language-Tag] [CFWS] "," [CFWS]) [Language-Tag [CFWS]]
   N.B. like the 2822 obs- lists, that provides for a list
   consisting of one or more commas, i.e. with no Language-Tag.
   To be more consistent with the 822 EBNF:
   obs-language-list = *([Language-Tag] [CFWS] "," [CFWS]) 
                       Language-Tag *([CFWS] "," [Language-Tag]) [CFWS]

Best regards,
  Bruce Lilly