[whatwg] HTML5 Definition of week (section

David Singer singer at apple.com
Mon Jul 20 10:45:51 PDT 2009

At 10:45  +0000 19/07/09, Ian Hickson wrote:
>On Fri, 3 Jul 2009, SJ Kissane wrote:
>>  I am concerned by the wording of this section. There are different
>>  systems of week number -- as far as I can work out, this is the same as
>>  ISO 8601 week numbering. But it nowhere explicitly says that.
>>  I think, the spec should have a normative reference to ISO 8601 for the
>>  definition of week numbering. Then, if the spec wants to give an
>>  informative recap of what ISO 8601 says, for the benefit of those who
>>  don't have a copy (especially since it isn't free), that's fine. But I'm
>>  worried, by inserting some complicated definition into the spec, does it
>>  match exactly ISO 8601's definition? (I'm sure it does, but "are the
>>  definitions the same?" is not immediately obvious from inspection.)
>They are not the same. ISO8601 doesn't define how you parse a week string,
>how you handle errors in such a string, and so forth. The numbers are
>compatible, and a valid HTML5 week string is an ISO8601 week string
>(though I don't know if the opposite is the case), but that's about it.
>While we could have an non-normative reference, in practice, it wouldn't
>add much, since (a) the HTML5 spec defines everything you might get from
>ISO8601, and (b) we don't want to have implementors think "oh, it's the
>same as ISO8601, I'll just use an ISO8601 date library", since such a
>library might get the parsing details wrong in terms of what HTML5 says.

an informative note to that effect might be a good idea.

>Ian Hickson               U+1047E                )\._.,--....,'``.    fL
>http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
>Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

David Singer
Multimedia Standards, Apple Inc.

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