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Re: [Scheme-reports] Date/time package

John Cowan <cowan@x> writes:
> John J Foerch scripsit:
>> Question: what do you mean by the terms "julian" and "gregorian"?
> Those plus the ISO and TAI chronologies are all proleptic, and I have
> added language to that effect.
>>   Astronomical year numbering: includes a year zero.  Used in
>>   astronomy.
> The ISO chronology has astronomical years, a Monday week-start, and
> numbers its centuries in Italian style (century 15 is 1500-1599).
>> As a general-purpose library, it would be nice for the user to be able
>> to specify all of these things, depending on the application.  (I have
>> genealogy and astronomy applications in mind.)
> As I noted, there is no portable way to specify a new base chronology.

I had in mind that these options would be provided via optional
chronologies, not as the base chronology.

>> There is also the can of worms of when the gregorian reform was
>> adopted in different countries.  If a person wants to work with
>> historical dates, it would be important to be able to express these
>> differences as different chronologies.
> Hence make-compound-chronology.


>> On a related topic, formatting, there was some discussion in this
>> thread about how the ISO8601 is closely tied to its particular
>> chronology.
> Well, at least to Western-style chronologies.

Yes, that is all I had in mind.  8601 format is more generally useful to
western chronologies, beyond its official one.

John Foerch

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