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> today is 20 Messidor, an 225 Hmm... according to my own implementation of the calendar[0] we are actually 30 Messidor, an 225. Same according to the Android

> today is 20 Messidor, an 225 Hmm... according to my own implementation of the calendar[0] we are actually 30 Messidor, an 225. Same according to the Android app I use on my phone. Do you have a link to the source of Emacs' implementation? [0] https://github.com/seeschloss/floreal https://github.com/seeschloss/floreal and a graphical calendar here: http://ssz.fr/republique/ http://ssz.fr/republique/ Edit thinking about it, many implementations do not really go beyond 1806 and do not count leap years (année sextiles which have six extra days instead of five) after then (as before this date, leap years were supposed to be calculated from the actual sun movements instead of regularly spaced). This might be the reason for the change.

laurentoget 9y ago
My version of Emacs (GNU Emacs 24.5.1) returns 30 Messidor as well
andrelaszlo 9y ago
http://www.windhorst.org/calendar/ http://www.windhorst.org/calendar/ This page explains the inconsistencies. Apparently there are several ways to calculate the dates past 1806.
- seszett 9y ago
  This is a ten-day difference though, which isn't really explained by leap year calculation differences/ Also, while it was never really formalised, the Paris Commune in 1871 (year LXXIX) actually confirmed in an indirect way the Romme method of calculating leap years (every four years, except every 100 years, except every 400 years) by shortly using the Republican calendar. I have a hard time understanding this language though https://opensource.apple.com/source/emacs/emacs-54/emacs/lisp/calendar/cal-french.el.auto.html https://opensource.apple.com/source/emacs/emacs-54/emacs/lis... so I'm not sure where it goes wrong (or right).
- irrational 9y ago
  Pfff. Dates up to 1806 should be good enough for anybody.
theophrastus 9y ago
I believe the emacs implementation is due to Reingold and Dershowitz[1] On page 11 of this pdf they give quite a bit of detail about the calculation of French Revolutionary Calendar, (including leap year complications). [1] http://www.reingold.co/cc2-paper.pdf http://www.reingold.co/cc2-paper.pdf

laurentoget 9y ago

My version of Emacs (GNU Emacs 24.5.1) returns 30 Messidor as well

andrelaszlo 9y ago

http://www.windhorst.org/calendar/ http://www.windhorst.org/calendar/ This page explains the inconsistencies. Apparently there are several ways to calculate the dates past 1806.

seszett 9y ago
This is a ten-day difference though, which isn't really explained by leap year calculation differences/ Also, while it was never really formalised, the Paris Commune in 1871 (year LXXIX) actually confirmed in an indirect way the Romme method of calculating leap years (every four years, except every 100 years, except every 400 years) by shortly using the Republican calendar. I have a hard time understanding this language though https://opensource.apple.com/source/emacs/emacs-54/emacs/lisp/calendar/cal-french.el.auto.html https://opensource.apple.com/source/emacs/emacs-54/emacs/lis... so I'm not sure where it goes wrong (or right).
irrational 9y ago
Pfff. Dates up to 1806 should be good enough for anybody.

theophrastus 9y ago

I believe the emacs implementation is due to Reingold and Dershowitz[1] On page 11 of this pdf they give quite a bit of detail about the calculation of French Revolutionary Calendar, (including leap year complications). [1] http://www.reingold.co/cc2-paper.pdf http://www.reingold.co/cc2-paper.pdf