[whatwg] Dates and coordinates in HTML5

Andy Mabbett andy at pigsonthewing.org.uk
Sat Feb 28 14:39:43 PST 2009

In message <49A5D6E8.5070907 at lachy.id.au>, Lachlan Hunt 
<lachlan.hunt at lachy.id.au> writes

>[Resending this to the list now that the problem that prevented it from 
>accepting any mail has been fixed.]


>Andy Mabbett wrote:
>>         Use-cases for machine-readable date mark-up are many: as well as
>>         the aforesaid calendar interactions, they can be used for
>>         sorting; for searching ("find me all the pages about events in
>>         1923" — recent developments in Yahoo's YQL searching API
>>         (which now supports searching for microformats):
>>          have opened up a whole new set of possibilities, which is 
>>         just beginning to be explored). They can be mapped visually on a
>>         "SIMILE"
>>            <http://simile.mit.edu/timeline/>
>>          or similar time-line.
>Neither of those appear to be using BCE dates, non-Gregorian calendars
>or imprecise dates.  It's not clear how they are use cases for the
>features that you are asking for.

I haven't tried using Yahoo to search for BCE or imprecise dates (I 
don't have the coding sills to construct such a search), but I don't see 
why that wouldn't work, since both are supported and published in 
hCard/hCalendar and ISO8601, and Yahoo say they support hCard/hCalendar, 
which use ISO8601.

Incidentally, the <time> element and BCE dates are both supported by the 
microformat parser "Swignition":


If Yahoo aren't supporting searches for such non-Gregorian dates, that's 
probably because there is currently no method of marking them up. Do we 
really have to illustrate use cases in action, before we can develop the 
technology which allows them to be demonstrated exists?

On the other hand, this SIMILE timeline has dates which are BCE, 
imprecise and non-Gregorian:


I note that you make no comment about the other use-cases I gave.

Andy Mabbett

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