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Edward C. Zimmermann wrote:

> Ranges are quite well defined in the ISO specification.

Could you please summarize the exact specification, so we all known what 
we are talking about?

> Technically also year, month, week, day and hour precisions are specifiable.
 > But we want, perhaps other precisions such as decade and century.. 
and some
 > fuzziness and uncertainty. That's where these ?, u, ~, [] and {} enter
 > the scene for date.
>
> These can then be applied to ranges as well....

But not based on implicit assumptions an vague ideas.

> We already have Glob with patterns such as
>
> [123] to match 1, 2 or 3
> [0-9] to match 0,1,2,3,4,5,6,7,8 or 9
> [^123] to match anything but 1,2 or 3.
>
> and () for grouping.

You should *not* full regular expressions without a serious mathematical 
treatment of the underlying model.

> '156?-12-25'
> December 25 sometime during the 1560s ('?' := questionable)

But I would read this as December 25 in a questionable year that is 
assumed to be 156.

> to contrast to:
>
> '156u-12-25'
>
> Which would be December 25 in the 1560s, but it is not certain which year ('u'
> := unknown)

Which can also be expressed as

[1560,1561,1562,1563,1564,1565,1566,1567,1568,1569]-12-25

right? By the way I don't like the overloading of the minus sign, so 
instead of

[1560-1569]-12-25

The abbreviation should be

[1560..1569]-12-25

> The question is: Do we want to allow (as in Glob) things like:
>
> 2005-06-1[5-8]  (as equivalent to 2005-06-[15-18] )

Defintely not, and I'd prefer 2005-06-[15..18].

> And how about
>
> 2004-0[1,2,3]-[2,3][0-9]
>
> [Feb has only 28 or, in leap years, 29 days so there is no 30 Feb and no month
> has 32 or more days]

These will all be enough:

2004-[1,2,3]-uu
2004-[1,2,3]-xx
2004-[1,2,3]-[1..31]

Unless you prepend an 'E' for extension times, there is no February 30.

Jakob

P.S: We definitely need to define a formal grammar (e.g. in Backus-Naur 
Syntax) for extended date/time notation.

-- 
Jakob Vo▀ <[log in to unmask]>, skype: nichtich
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