Re: [xml-dev] Here's the regex for the xs:dateTime datatype

[Peter Flynn <peter@silmaril.ie>]

On 14/08/18 10:35, David Carlisle wrote:
> On Mon, 13 Aug 2018 at 22:59, Liam R. E. Quin <liam@fromoldbooks.org> wrote:
>>
>> On Mon, 2018-03-31 at 29:75 +0100, Michael Kay wrote:
>>> Both of these regular expressions allow any month to have 31 days.
>>> For that reason, I'm not sure either of them is particularly useful.
> 
> I suppose you could replace
> 
> -(0[1-9]|1[0-2])
> -(0[1-9]|[12][0-9]|3[01])
> 
> by something like
> -
> (
> ((0[13578]|12)-(0[1-9]|[12][0-9]|3[01]))
> |
> (02-(0[1-9]|[12])[0-9])
> |
> ((0[469]|11)-(0[1-9]|[12][0-9]|30))
> )
> 
> But it would still allow any year to be a leap year, I don't fancy
> trying to encode the leap year rules as a regex:-)
> 
> Also this doesn't account for any historic dates around calendar
> changes with variant numbers of days in a month.

Humans tend to have an advantage in pattern-recognition at this level of
validation. One reason why my preferred name for a date attribute is
YYYY-MM-DD. It's not as elegant and it's culturally insensitive, but
since I started using it, I have had zero validation problems from my
authors and editors.

///Peter