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 -----Original Message-----
 From: Discussion of the Developing Date/Time Standards
 [mailto:[log in to unmask]] On Behalf Of Per Bothner

> I agree parsimony argues for "if it is a feature supported by ISO 8601,
> will be prescribed in a manner compatible with ISO 8601", but I don't
> violating that rule breaks much.  To parse an EDTF specifier one needs
> a EDTF-aware processor. and a 8601 processor won't cut it

True, but the reason for the rule (in my view) is this. The long-range plan
for this specification is to submit it to ISO as a (or as part of a) future
version of 8601.   

I don't mean to get too far ahead of myself. So I don't want to talk about
this in much detail except to say: there are no concrete plans to do this,
and the spec will likely be taken to some other body first, W3C or IETF for
example. But it is hoped that subseqently it can be considered for adoption
into 8601. The likelihood and desirability of this is certainly an
appropriate topic for discussion.

So, if this really is the goal, then we really are not in a position to
violate 8601, unless we are prepared to argue to ISO that they made a
mistake when they assigned the "/" character for this role and try to
convince them to change it; which I think would be a losing battle.


> I noted an inconsistency for "Uncertain, but known to be one of a set."
>     [1667,1668, 1670-1672]
>     One of the years 1667, 1668, 1670, 1671, 1672 In this context,
> we're using hyphens for a set.
> 
> I recommend just using ".." for an interval, so the above would be:
>    [1667,1668, 1670..1672]
> What about when "The endpoint of an interval is another interval"?
> One option is to use parentheses - after all we already use parentheses
> for grouping of questionable dates, which this is, so instead of:
> 
>    20030312/20030319//20030320/20030321
> we'd use:
>    (20030312..20030319)..(20030320..20030321)
>

We have to distinguish "the endpoint of an interval is another interval"
from "the end point of an interval is a choice among several consecutive
years"; an interval is a continuous period, vs. a discrete set of
(consecutive years).  

So if we want to express, let's say "the interval beginning with one of the
years 1670, 1671, 1672 and ending 1680" 
it would be  

    [1670, 1671, 1672]/1680
or
    [1670-1672]/1680

On the other hand if you want to express "the interval beginning sometime
within the interval beginning in 1670 and ending in 1672 and ending 1680"
it would be

    1670/1672//1680

 
> Alternatively, we can use square brackets, since presumably an
> "internals of intervals" really means that the endpoint is "Uncertain,
> but known to be one of a set".  Thus:
> 
>    [20030312..20030319]..[20030320..20030321]

Yes, for the "discrete year" case as discussed above.  However, let's leave
the "..." vs. "/" open for further discussion, for now. 



> 
> On a related note, we can possibly get rid of the "Before/after
> indicator".
> Instead of:
>    .be.1760
> I think this would be more readable:
>    [..1760]
> If you need "before" rather than "before or equal" you could do:
>    [..<1760-12-03]
> instead of:
>    .bf.1760-12-03

There may be preferable alternatives to the .xx. syntax currently proposed.
I'm fairly sure however that we don't want to introduce angle brackets,
because after all this spec is intended to be used heavily with XML.   

Comments welcome on this issue.

Thanks much for the comments.
 

--Ray