[uf-dev] The correct format of a ISO date

[Toby A Inkster]

Mark Norman Francis wrote:

> Actually, according to the Wikipedia page on ISO 8601:
> > ISO 8601 prescribes, as a minimum, a four-digit year [YYYY] to avoid
> > the year 2000 problem.

The confusion is due to the fact that there are three editions of ISO  
8601:

	ISO 8601:1988 (E)
	ISO 8601:2000 (E)
	ISO 8601:2004 (E)

The first two allow two-digit years. The most recent edition  
disallows them, but IIRC parsers are still expected to accept them,  
as they may be produced by legacy ISO 8601 code.

Also worth consideration are date formats like:

	--05-23	(Day and month; year not specified)
	---23 (Day; month and year not specified)
	-145 (Ordinal day; year not specified)
	-W21-5 (Week and day; year not specified)

Oh, and commas are allowed to be used as decimal points. Oh, and  
decimals are not just allowed after seconds, but also after minutes  
and hours. It is for these reasons that we really must specify a  
subset of ISO 8601 -- the W3CDTF subset would be idea.

-- 
Toby A Inkster
<mailto:mail at tobyinkster.co.uk>
<http://tobyinkster.co.uk>