calendar
Homepage: https://www.gnu.org/software/emacs
Author: Edward M. Reingold
Summary
Calendar functions
Commentary
This collection of functions implements a calendar window. It
generates a calendar for the current month, together with the
previous and coming months, or for any other three-month period.
The calendar can be scrolled forward and backward in the window to
show months in the past or future; the cursor can move forward and
backward by days, weeks, or months, making it possible, for
instance, to jump to the date a specified number of days, weeks, or
months from the date under the cursor. The user can display a list
of holidays and other notable days for the period shown; the
notable days can be marked on the calendar, if desired. The user
can also specify that dates having corresponding diary entries (in
a file that the user specifies) be marked; the diary entries for
any date can be viewed in a separate window. The diary and the
notable days can be viewed independently of the calendar. Dates
can be translated from the (usual) Gregorian calendar to the day of
the year/days remaining in year, to the ISO commercial calendar, to
the Julian (old style) calendar, to the Hebrew calendar, to the
Islamic calendar, to the Bahá’í calendar, to the French
Revolutionary calendar, to the Mayan calendar, to the Chinese
calendar, to the Coptic calendar, to the Ethiopic calendar, and to
the astronomical (Julian) day number. Times of sunrise/sunset can
be displayed, as can the phases of the moon. Appointment
notification for diary entries is available. Calendar printing via
LaTeX is available.
The following files are part of the calendar/diary code:
appt.el Appointment notification
cal-bahai.el Bahá’í calendar
cal-china.el Chinese calendar
cal-coptic.el Coptic/Ethiopic calendars
cal-dst.el Daylight saving time rules
cal-french.el French revolutionary calendar
cal-hebrew.el Hebrew calendar
cal-html.el Calendars in HTML
cal-islam.el Islamic calendar
cal-iso.el ISO calendar
cal-julian.el Julian/astronomical calendars
cal-mayan.el Mayan calendars
cal-menu.el Menu support
cal-move.el Movement in the calendar
cal-persia.el Persian calendar
cal-tex.el Calendars in LaTeX
cal-x.el Dedicated frame functions
calendar.el This file
diary-lib.el Diary functions
holidays.el Holiday functions
lunar.el Phases of the moon
solar.el Sunrise/sunset, equinoxes/solstices
Technical details of all the calendrical calculations can be found in
"Calendrical Calculations: The Ultimate Edition" by Edward M. Reingold
and Nachum Dershowitz, Cambridge University Press (2018).
An earlier version of the technical details appeared in "Calendrical
Calculations" by Nachum Dershowitz and Edward M. Reingold,
Software--Practice and Experience, Volume 20, Number 9 (September, 1990),
pages 899-928
,
and in "Calendrical Calculations, Part II: Three Historical Calendars" by
E. M. Reingold, N. Dershowitz, and S. M. Clamen, Software--Practice and
Experience, Volume 23, Number 4 (April, 1993), pages 383-404
A note on free variables:
The calendar passes around a few dynamically bound variables, which
unfortunately have rather common names. They are meant to be
available for external functions, so the names can't be changed.
displayed-month, displayed-year: bound in calendar-generate, the
central month of the 3 month calendar window
original-date, number: bound in diary-list-entries, the arguments
with which that function was called.
date, entry: bound in diary-list-sexp-entries (qv)
Bound in diary-list-entries:
diary-entries-list: use in d-l, appt.el, and by diary-add-to-list
diary-saved-point: only used in diary-lib.el, passed to the display func
date-string: only used in diary-lib.el
list-only: don't modify the diary-buffer, just return a list of entries
file-glob-attrs: yuck
Dependencies
Reverse dependencies