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Re: [xsl] Re: format-date() and negative (BCE) dates


Subject: Re: [xsl] Re: format-date() and negative (BCE) dates
From: "Paul Tyson phtyson@xxxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
Date: Wed, 7 May 2014 19:18:18 -0000

> On May 7, 2014, at 13:59, "Martin Holmes gtxxgm-xsl-list-2@xxxxxxxxxxx"
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hi Liam,
>
>> On 14-05-07 10:52 AM, Liam R E Quin liam@xxxxxx wrote:
>> On Tue, 2014-05-06 at 23:50 +0000, Martin Holmes
>> gtxxgm-xsl-list-2@xxxxxxxxxxx wrote:
>>
>>> The proleptic Gregorian doesn't, I agree, make much sense when it's
>>> extended this far back, but the project I'm working on is an early
>>> modern one, and most of our date-conversion functions convert between
>>> Julian and Gregorian.
>>
>> It's worth mentioning for the sake of people thinking the Julian
>> calendar is convenient in general that different countries adopted the
>> Gregorian calendar at different times - as late as the 1930s for Greece,
>> 1752 in the UK, 16th Century for much of Roman Catholic Europe, and an
>> even more complex picture in the Americas.
>
> Yes, and even worse, the date of the beginning of the year varies even
during the time when Julian is used in a single country.
>
>> The other historical form commonly seen is to date events in terms of
>> people, usually monarchs. E.g. 3 Geo III would be the third year of the
>> reign of George III, although as far as I can tell the usual year end
>> was employed, so that the years were measured in England (say) from
>> April 1st, not from the coronation or accession date.
>
> Yes, we have regnal dates too. Our normal procedure is to mark them up as
regnal dates, but supply TEI custom dating attributes specifying what they
would be in Julian; then the automated conversion is able to supply proleptic
Gregorian equivalents.
>
> All the conversions are intended only as helpful information; they can't
usually be accurate, especially for dates in the first three months of the
year, because of the difficulty of knowing what year-end the writer happened
to be using.
>
>>>  Older dates tagged as Julian also come in for the
>>> same conversion. You're right that it's ambiguous, though; this page:
>>> <http://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar> shows a
>>> table in which 1BC Julian is equivalent to 1BC Gregorian, but it also
>>> appears to suggest that ISO 8601 is somehow equivalent to proleptic
>>> Gregorian.
>>
>> It is also overly simplistic, for the reasons I already mentioned. Since
>> dates don't usually mention the calendar to which they conform, you have
>> to add context. And, of course, a visitor from France to England writing
>> home would most likely use the French calendar of the time, perhaps
>> eventually switching after staying in England more than a year or two.
>>
>> There's a book on Calendrical Calculations, although I seem to remember
>> that it's awfully proprietary, in that the author claims ownership of
>> the algorithms. But it looked as if it might be helpful.
>
> The resource we use most is:
>
> Cheney, C.R. 2000. A Handbook of Dates for students of British history.
Revised by Michael Jones. Cambridge: Cambridge University Press.
>
> It's wonderfully detailed and unexpectedly enjoyable to read.
>

As is Calendrical Calculations [1]. I don't think that the algorithms are
proprietary. They run the emacs calendar, so FSF has copyright on that code.
Since they are in lisp it would be easy to put them into xslt if that hasn't
been done already.

Regards,
--Paul

[1] http://www.calendarists.com

> Cheers,
> Martin
>
>
>>
>> Liam


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