@node Calendar/Diary, Sorting, Reading Mail, Top
@section Calendar Mode and the Diary
@cindex calendar
@findex calendar

  Emacs provides the functions of a desk calendar, with a diary of past
or planned events.  Display the calendar by typing @kbd{M-x calendar}.
This command creates a window containing a three-month calendar centered
on the current month, with point on the current date.  Or, provide a
prefix argument by typing @kbd{C-u M-x calendar}; then you are prompted
for the month and year to be the center of the three-month calendar.  In
either case, you are now in Calendar mode.

  Calendar mode makes it easy to look at the holidays or diary entries
associated with various dates, and to change the diary entries.  You can move
freely between the Calendar window and other windows.  To exit the calendar,
type @kbd{q}.

@menu
* Calendar Motion::        Moving through the calendar; selecting a date.
* Scroll Calendar::        Bringing earlier or later months onto the screen.
* Mark and Region::        Remembering dates, the mark ring.
* General Calendar::       Conveniences for moving about.
* Holidays::               Displaying dates of holidays.
* Sunrise/Sunset::         Displaying local times of sunrise and sunset.
* Lunar Phases::           Displaying phases of the moon.
* Other Calendars::        Converting dates to other calendar systems.
* Diary::                  Displaying events from your diary.
* Calendar Customization:: Altering the behavior of the features above.
@end menu

@node Calendar Motion, Scroll Calendar, Calendar/Diary, Calendar/Diary
@subsection Movement in the Calendar

  Calendar mode lets you move in logical units of time such as days,
weeks, months, and years.  Sometimes you need to move to a specific date
in order to enter commands affecting its display or the associated diary
entries.  If you move outside the three months originally displayed, the
calendar display scrolls automatically through time.

@menu
* Calendar Unit Motion::       Moving by days, weeks, months, and years.
* Move to Beginning or End::   Moving to start/end of weeks, months, and years.
* Specified Dates::            Moving to the current date or another specific date.
@end menu

@node Calendar Unit Motion, Move to Beginning or End, Calendar Motion, Calendar Motion
@subsubsection Motion by Integral Days, Weeks, Months, Years

  The commands for movement in the calendar buffer parallel the
commands for movement in text.  You can move forward and backward by
days, weeks, months, and years.

@table @kbd
@item C-f
Move point one day forward (@code{calendar-forward-day}).
@item C-b
Move point one day backward (@code{calendar-backward-day}).
@item C-n
Move point one week forward (@code{calendar-forward-week}).
@item C-p
Move point one week backward (@code{calendar-backward-week}).
@item M-@}
Move point one month forward (@code{calendar-forward-month}).
@item M-@{
Move point one month backward (@code{calendar-backward-month}).
@item C-x ]
Move point one year forward (@code{calendar-forward-year}).
@item C-x [
Move point one year backward (@code{calendar-forward-year}).
@end table

@kindex C-f (Calendar mode)
@findex calendar-forward-day
@kindex C-b (Calendar mode)
@findex calendar-backward-day
@kindex C-n (Calendar mode)
@findex calendar-forward-week
@kindex C-p (Calendar mode)
@findex calendar-backward-week
  The day and week commands are natural analogues of the usual Emacs
commands for moving by characters and by lines.  Just as @kbd{C-n}
usually moves to the same column in the following line, in Calendar
mode it moves to the same day in the following week.  And @kbd{C-p}
moves to the same day in the previous week.

@kindex M-@} (Calendar mode)
@findex calendar-forward-month
@kindex M-@{ (Calendar mode)
@findex calendar-backward-month
@kindex C-x ] (Calendar mode)
@findex calendar-forward-year
@kindex C-x [ (Calendar mode)
@findex calendar-forward-year
  The commands for motion by months and years work like those for
weeks, but move a larger distance.  The month commands @kbd{M-@}} and
@kbd{M-@{} move forward or backward by an entire month's time.  The
year commands @kbd{C-x ]} and @kbd{C-x [} move forward or backward a
whole year.

  The easiest way to remember these commands is to consider months and
years analogous to paragraphs and pages of text, respectively.  But the
commands themselves are not quite analogous.  The ordinary Emacs paragraph
commands move to the beginning or end of a paragraph, whereas these month
and year commands move by an entire month or an entire year, which usually
involves skipping across the end of a month or year.

  Each of these commands accepts a numeric argument as a repeat count.  For
convenience, the digit keys and the minus sign are bound in Calendar mode so
that it is unnecessary to type the @kbd{M-} prefix.  For example, @kbd{100
C-f} moves point 100 days forward from its present location.

@node Move to Beginning or End, Specified Dates, Calendar Unit Motion, Calendar Motion
@subsubsection Beginning or End of Week, Month or Year

  A week (or month, or year) is not just a quantity of days; we think
of new weeks (months, years) as starting on particular days.  So
Calendar mode provides commands to move to the beginning or end of the
week, month or year:

@table @kbd
@kindex C-a (Calendar mode)
@findex calendar-beginning-of-week
@item C-a
Move point to beginning of week (@code{calendar-beginning-of-week}).
@kindex C-e (Calendar mode)
@findex calendar-end-of-week
@item C-e
Move point to end of week (@code{calendar-end-of-week}).
@kindex M-a (Calendar mode)
@findex calendar-beginning-of-month
@item M-a
Move point to beginning of month (@code{calendar-beginning-of-month}).
@kindex M-e (Calendar mode)
@findex calendar-end-of-month
@item M-e
Move point to end of month (@code{calendar-end-of-month}).
@kindex M-< (Calendar mode)
@findex calendar-beginning-of-year
@item M-<
Move point to beginning of year (@code{calendar-beginning-of-year}).
@kindex M-> (Calendar mode)
@findex calendar-end-of-year
@item M->
Move point to end of year (@code{calendar-end-of-year}).
@end table

  These commands also take numeric arguments as repeat counts, with the
repeat count indicating how many weeks, months, or years to move
backward or forward.

@node Specified Dates,,Move to Beginning or End, Calendar Motion
@subsubsection Particular Dates

  Calendar mode provides some commands for getting to a particular date
quickly.

@table @kbd
@item g d
Move point to specified date (@code{calendar-goto-date}).
@item o
Center calendar around specified month (@code{calendar-other-month}).
@item .
Move point to today's date (@code{calendar-current-month}).
@end table

@kindex g d (Calendar mode)
@findex calendar-goto-date
  @kbd{g d} (@code{calendar-goto-date}) prompts for a year, a month, and a day
of the month, and then goes to that date.  Because the calendar includes all
dates from the beginning of the current era, you must type the year in its
entirety; that is, type @samp{1990}, not @samp{90}.

@kindex o (Calendar mode)
@findex calendar-other-month
  @kbd{o} (@code{calendar-other-month}) prompts for a month and year,
then centers the three-month calendar around that month.

@kindex . (Calendar mode)
@findex calendar-current-month
  You can return to the current date with @kbd{.}
(@code{calendar-current-month}).

@node Scroll Calendar, Mark and Region, Calendar Motion, Calendar/Diary
@subsection Scrolling the Calendar through Time

  The calendar display scrolls automatically through time when you move out
of the visible portion.  You can also scroll it manually.  Imagine that the
calendar window contains a long strip of paper with the months on it.
Scrolling it means moving the strip so that new months become visible in
the window.

@table @kbd
@item C-x <
Scroll calendar one month forward (@code{scroll-calendar-left}).
@item C-x >
Scroll calendar one month backward (@code{scroll-calendar-right}).
@item C-v
Scroll calendar three months forward
(@code{scroll-calendar-left-three-months}).
@item M-v
Scroll calendar three months backward
(@code{scroll-calendar-right-three-months}).
@end table

@kindex C-x < (Calendar mode)
@findex scroll-calendar-left
@kindex C-x > (Calendar mode)
@findex scroll-calendar-right
  The most basic calendar scroll commands scroll by one month at a
time.  This means that there are two months of overlap between the
display before the command and the display after.  @kbd{C-x <} scrolls
the calendar contents one month to the left; that is, it moves the
display forward in time.  @kbd{C-x >} scrolls the contents to the
right, which moves backwards in time.

@kindex C-v (Calendar mode)
@findex scroll-calendar-left-three-months
@kindex M-v (Calendar mode)
@findex scroll-calendar-right-three-months
  The commands @kbd{C-v} and @kbd{M-v} scroll the calendar by an entire
``screenful''---three months---in analogy with the usual meaning of these
commands.  @kbd{C-v} makes later dates visible and @kbd{M-v} makes earlier
dates visible.  These commands also take a numeric argument as a repeat
count; in particular, since @kbd{C-u} (@code{universal-argument}) multiplies
the next command by four, typing @kbd{C-u C-v} scrolls the calendar forward by
a year and typing @kbd{C-u M-v} scrolls the calendar backward by a year.

  Any of the special Calendar mode commands scrolls the calendar automatically
as necessary to ensure that the date you have moved to is visible.

@node Mark and Region, General Calendar, Scroll Calendar, Calendar/Diary
@subsection The Mark and the Region

  The concept of the mark applies to the calendar just as to any other
buffer, but it marks a @emph{date}, not a @emph{position} in the buffer.
The region consists of the days between the mark and point (including
the starting and stopping dates).

@table @kbd
@item C-SPC
Set the mark to today's date (@code{calendar-set-mark}).
@item C-@@
The same.
@item C-x C-x
Interchange mark and point (@code{calendar-exchange-point-and-mark}).
@item M-=
Display the number of days in the current region
(@code{calendar-count-days-region}).
@end table

@kindex C-@@ (Calendar mode)
@kindex C-SPC (Calendar mode)
@findex calendar-set-mark
@kindex C-x C-x (Calendar mode)
@findex calendar-exchange-point-and-mark
  You set the mark in the calendar, as in any other buffer, by using @kbd{C-@@}
or @kbd{C-SPC} (@code{calendar-set-mark}).  You return to the marked date
with the command @kbd{C-x C-x} (@code{calendar-exchange-point-and-mark})
which puts the mark where point was and point where mark was.  The calendar
is scrolled as necessary, if the marked date was not visible on the
screen.  This does not change the extent of the region.

@kindex M-= (Calendar mode)
@findex calendar-count-days-region
  To determine the number of days in the region, type @kbd{M-=}
(@code{calendar-count-days-region}).  The numbers of days printed is
@emph{inclusive}, that is, includes the days specified by mark and point.

@cindex mark ring
  The main use of the mark in the calendar is to remember dates that you may
want to go back to.  To make this feature more useful, the mark ring
(@pxref{Mark Ring}) operates exactly as in other buffers:  Emacs remembers
16 previous locations of the mark.  To return to a marked date, type @kbd{C-u
C-SPC} (or @kbd{C-u C-@@}); this is the command @code{calendar-set-mark} given
a numeric argument.  It moves point to where the mark was, restores the mark
from the ring of former marks, and stores the previous point at the end of
the mark ring.  So, repeated use of this command moves point through all
the old marks on the ring, one by one.

@node General Calendar, Holidays, Mark and Region, Calendar/Diary
@subsection Miscellaneous Calendar Commands

@table @kbd
@item p d
Display day-in-year (@code{calendar-print-day-of-year}).
@item ?
Briefly describe calendar commands (@code{describe-calendar-mode}).
@item SPC
Scroll the next window (@code{scroll-other-window}).
@item C-c C-l
Regenerate the calendar window (@code{redraw-calendar}).
@item q
Exit from calendar (@code{exit-calendar}).
@end table

@kindex p d (Calendar mode)
@cindex day of year
@findex calendar-print-day-of-year
  If you want to know how many days have elapsed since the start of
the year, or the number of days remaining in the year, type the @kbd{p d}
command (@code{calendar-print-day-of-year}).  This displays both
of those numbers in the echo area.

@kindex ? (Calendar mode)
@findex describe-calendar-mode
  To display a brief description of the calendar commands, type @kbd{?}
(@code{describe-calendar-mode}).  For a fuller description, type @kbd{C-h m}.

@kindex SPC (Calendar mode)
@findex scroll-other-window
  You can use @kbd{SPC} (@code{scroll-other-window}) to scroll the other
window.  This is handy when you display a list of holidays or diary entries
in another window.

@kindex C-c C-l (Calendar mode)
@findex redraw-calendar
  If the calendar window gets corrupted, type @kbd{C-c C-l}
(@code{redraw-calendar}) to redraw it.

@kindex q (Calendar mode)
@findex exit-calendar
  To exit from the calendar, type @kbd{q} (@code{exit-calendar}).  This
buries all buffers related to the calendar and returns the window display
to what it was when you entered the calendar.

@node Holidays, Sunrise/Sunset, General Calendar, Calendar/Diary
@subsection Holidays
@cindex holidays

  The Emacs calendar knows about all major and many minor holidays.

@table @kbd
@item h
Display holidays for the date indicated by point
(@code{calendar-cursor-holidays}).
@item x
Mark holidays in the calendar window (@code{mark-calendar-holidays}).
@item u
Unmark calendar window (@code{calendar-unmark}).
@item a
List all holidays for the displayed three months in another window
(@code{list-calendar-holidays}).
@item M-x holidays
List all holidays for three months around today's date in another
window.
@end table

@kindex h (Calendar mode)
@findex calendar-cursor-holidays
  To see if any holidays fall on a given date, position point on that
date in the calendar window and use the @kbd{h} command.  The holidays
are usually listed in the echo area, but if there are too many to fit in
one line, then they are displayed in a separate window.

@kindex x (Calendar mode)
@findex mark-calendar-holidays
@kindex u (Calendar mode)
@findex calendar-unmark
  To find the distribution of holidays for a wider period, you can use the
@kbd{x} command.  This places a @samp{*} next to every date on which a holiday
falls.  The command applies both to the currently visible dates and to new
dates that become visible by scrolling.  To turn marking off and erase the
current marks, type @kbd{u}, which also erases any diary marks (@pxref{Diary}).

@kindex a (Calendar mode)
@findex list-calendar-holidays
  To get even more detailed information, use the @kbd{a} command, which
displays a separate buffer containing a list of all holidays in the
current three-month range.

@findex holidays
  You can display the list of holidays for the current month and the
preceding and succeeding months even if you don't have a calendar
window.  Use the command @kbd{M-x holidays}.  If you want the list of
holidays centered around a different month, use @kbd{C-u M-x holidays}
and type the month and year.

  The holidays known to Emacs include American holidays and the major
Christian, Jewish, and Islamic holidays; when floating point is available,
Emacs also knows about solstices and equinoxes.  The dates used by Emacs
for holidays are based on @emph{current practice}, not historical fact.
Historically, for instance, the start of daylight savings time and even
its existence have varied from year to year.  However present American
law mandates that daylight savings time begins on the first Sunday in
April; this is the definition that Emacs uses, even though it is wrong
for some prior years.

@node Sunrise/Sunset, Lunar Phases, Holidays, Calendar/Diary
@subsection Times of Sunrise and Sunset
@cindex sunrise
@cindex sunset

  Emacs can tell you, to within a minute or two, the times of sunrise and
sunset for any date, if floating point is available.

@table @kbd
@item S
Display times of sunrise and sunset for the date indicated by point
(@code{calendar-sunrise-sunset}).
@item M-x sunrise-sunset
Display times of sunrise and sunset for today's date.
@end table

@kindex S (Calendar mode)
@findex calendar-sunrise-sunset
@findex sunrise-sunset
  Move point to the date you want, and type @kbd{S}, to display the
@emph{local times} of sunrise and sunset in the echo area.

  You can display the times of sunrise and sunset for the current date
even if you don't have a calendar window.  Use the command @kbd{M-x
sunrise-sunset}.  If you want the times of sunrise and sunset for a
different date, use @kbd{C-u M-x sunrise-sunset} and type the year,
month, and day.

  Because the times of sunrise and sunset depend on the location on
earth, you need to tell Emacs your latitude, longitude, and location
name.  Here is an example of what to set:

@vindex calendar-location-name
@vindex calendar-longitude
@vindex calendar-latitude
@example
(setq calendar-latitude 40.1)
(setq calendar-longitude -88.2)
(setq calendar-location-name "Urbana, IL")
@end example

@noindent
Use one decimal place in the values of @code{calendar-latitude} and
@code{calendar-longitude}.

  Your time zone also affects the local time of sunrise and sunset.
Emacs usually gets this information from the operating system, but if
these values are not what you want (or if the operating system does not
supply them), you'll need to set them yourself, like this:

@vindex calendar-time-zone
@vindex calendar-standard-time-zone-name
@vindex calendar-daylight-time-zone-name
@example
(setq calendar-time-zone -360)
(setq calendar-standard-time-zone-name "CST")
(setq calendar-daylight-time-zone-name "CDT")
@end example

@noindent
The value of @code{calendar-time-zone} is the number of minutes
difference between your local standard time and Universal Time
(Greenwich time).  The values of @code{calendar-standard-time-zone-name}
and @code{calendar-daylight-time-zone-name} are the abbreviations used
in your time zone.

  Emacs displays the times of sunrise and sunset @emph{corrected for
daylight savings time} (this convenience is unusual; most tables of
sunrise and sunset use standard time).  The default rule for the
starting and stopping dates of daylight savings time is the American
rule.  @xref{Daylight Savings}

  You can display the times of sunrise and sunset for any location and
any date with @kbd{C-u C-u M-x sunrise-sunset}.  Emacs asks you for a
longitude, latitude, number of minutes difference from Universal time,
and date, and then tells you the times of sunrise and sunset for that
location on that date.  The times are usually given in the echo area,
but if the message is too long fit in one line, they are displayed in a
separate window.

@node Lunar Phases, Other Calendars, Sunrise/Sunset, Calendar/Diary
@subsection Phases of the Moon
@cindex phases of the moon
@cindex moon, phases of

  Emacs can tell you the dates and times of the phases of the moon (new
moon, first quarter, full moon, last quarter), if floating point is available.

@table @kbd
@item M
List, in another window, the dates and times for all the quarters of the
moon for the three-month period shown in the calendar window
(@code{calendar-phases-of-moon}).
@item M-x phases-of-moon
List dates and times of the quarters of the moon for three months around
today's date in another window.
@end table

@kindex M (Calendar mode)
@findex calendar-phases-of-moon
  Use the @kbd{M} command to display a separate buffer of the phases of
the moon for the current three-month range.  The dates and times listed
are accurate to within a few minutes.  

@findex phases-of-moon
  You can display the list of the phases of the moon for the current
month and the preceding and succeeding months even if you don't have a
calendar window.  Use the command @kbd{M-x phases-of-moon}.  If you want
the phases of the moon centered around a different month, use @kbd{C-u
M-x phases-of-moon} and type the month and year.

@vindex calendar-time-zone
  The dates and times given for the phases of the moon are given in
local time (corrected for daylight savings, when appropriate); but if
the variable @code{calendar-time-zone} is void, Universal Time (the
Greenwich time zone) is used.  @xref{Daylight Savings}

@node Other Calendars, Diary, Lunar Phases, Calendar/Diary
@subsection Our Calendar and Other Calendars

@cindex Gregorian calendar
  The Emacs calendar displayed is @emph{always} the Gregorian calendar,
sometimes called the ``new style'' calendar, which is used in most of
the world today.  However, this calendar did not exist before the
sixteenth century and was not widely used before the eighteenth century;
it did not fully displace the Julian calendar and gain universal
acceptance until the early twentieth century.  This poses a problem for
the Emacs calendar: you can ask for the calendar of any month starting
with January, year 1 of the current era, but the calendar displayed is
the Gregorian, even for a date at which the Gregorian calendar did not
exist!

  Emacs knows about several different calendars, though, not just the
Gregorian calendar.  The following commands describe the date indicated
by point in various calendar notations:

@table @kbd
@item p c
Display ISO commercial calendar equivalent for selected day
(@code{calendar-print-iso-date}).
@item p j
Display Julian date for selected day (@code{calendar-print-julian-date}).
@item p a
Display astronomical (Julian) day number for selected day
(@code{calendar-print-astro-day-number}).
@item p h
Display Hebrew date for selected day (@code{calendar-print-hebrew-date}).
@item p i
Display Islamic date for selected day (@code{calendar-print-islamic-date}).
@item p f
Display French Revolutionary date for selected day
(@code{calendar-print-french-date}).
@item p m
Display Mayan date for selected day (@code{calendar-print-mayan-date}).
@end table

  If you are interested in these calendars, you can convert dates one at a
time.  Put point on the desired date of the Gregorian calendar and press the
appropriate keys.  The @kbd{p} is a mnemonic for ``print'' since Emacs
``prints' the equivalent date in the echo area.

@kindex p c (Calendar mode)
@findex calendar-print-iso-date
@cindex ISO commercial calendar
  The ISO commercial calendar is used largely in Europe.

@kindex p j (Calendar mode)
@findex calendar-print-julian-date
@cindex Julian calendar
  The Julian calendar, named after Julius Caesar, was the one used in Europe
throughout medieval times, and in many countries up until the nineteenth
century.

@kindex p a (Calendar mode)
@findex calendar-print-astro-day-number
@cindex Julian day numbers
@cindex astronomical day numbers
  Astronomers use a simple counting of days elapsed since noon, Monday,
January 1, 4713 B.C. on the Julian calendar.  The number of days elapsed
is called the @emph{Julian day number} or the @emph{Astronomical day number}.

@kindex p h (Calendar mode)
@findex calendar-print-hebrew-date
@cindex Hebrew calendar
  The Hebrew calendar is the one used to determine the dates of Jewish
holidays.  Hebrew calendar dates begin and end at sunset.

@kindex p i (Calendar mode)
@findex calendar-print-islamic-date
@cindex Islamic calendar
  The Islamic (Moslem) calendar is the one used to determine the dates
of Moslem holidays.  There is no universal agreement in the Islamic
world about the calendar; Emacs uses a widely accepted version, but the
precise dates of Islamic holidays often depend on proclamation by
religious authorities, not on calculations.  As a consequence, the
actual dates of occurrence can vary slightly from the dates computed by
Emacs.  Islamic calendar dates begin and end at sunset.

@kindex p f (Calendar mode)
@findex calendar-print-french-date
@cindex French Revolutionary calendar
  The French Revolutionary calendar was created by the Jacobins after the 1789
revolution, to represent a more secular and nature-based view of the annual
cycle, and to install a 10-day week in a rationalization measure similar to
the metric system.  The French government officially abandoned this
calendar at the end of 1805.

@kindex p m (Calendar mode)
@findex calendar-print-mayan-date
@cindex Mayan calendar
  The Maya of Central America used three separate, overlapping calendar
systems, the @emph{long count}, the @emph{tzolkin}, and the @emph{haab}.
Emacs knows about all three of these calendars.  Experts dispute the
exact correlation between the Mayan calendar and our calendar; Emacs uses the
Goodman-Martinez-Thompson correlation in its calculations.

  You can move to dates that you specify on the Commercial, Julian,
astronomical, Hebrew, Islamic, or French calendars:

@kindex g c (Calendar mode)
@findex calendar-goto-iso-date
@kindex g j (Calendar mode)
@findex calendar-goto-julian-date
@kindex g a (Calendar mode)
@findex calendar-goto-astro-day-number
@kindex g h (Calendar mode)
@findex calendar-goto-hebrew-date
@kindex g i (Calendar mode)
@findex calendar-goto-islamic-date
@kindex g f (Calendar mode)
@findex calendar-goto-french-date
@table @kbd
@item g c
Move point to a date specified by the ISO commercial calendar
(@code{calendar-goto-iso-date}).
@item g j
Move point to a date specified by the Julian calendar
(@code{calendar-goto-julian-date}).
@item g a
Move point to a date specified by astronomical (Julian) day number
(@code{calendar-goto-astro-day-number}).
@item g h
Move point to a date specified by the Hebrew calendar
(@code{calendar-goto-hebrew-date}).
@item g i
Move point to a date specified by the Islamic calendar
(@code{calendar-goto-islamic-date}).
@item g f
Move point to a date specified by the French Revolutionary calendar
(@code{calendar-goto-french-date}).
@end table

  These commands ask you for a date on the other calendar, move point to
the Gregorian calendar date equivalent to that date, and display the
other calendar's date in the echo area.  Emacs uses strict completion
(@pxref{Completion}) whenever it asks you to type a month name, so you
don't have to worry about the spelling of Hebrew, Islamic, or French names.

@findex list-yahrzeit-dates
@cindex yahrzeits
  One common question concerning the Hebrew calendar is the computation
of the anniversary of a date of death, called a ``yahrzeit.''  The Emacs
calendar includes a facility for such calculations.  If you are in the
calendar, the command @kbd{M-x list-yahrzeit-dates} asks you for a
range of years and then displays a list of the yahrzeit dates for those
years for the date given by point.  If you are not in the calendar,
this command first asks you for the date of death and the range of
years, and then displays the list of yahrzeit dates.

  Emacs also has many commands for movement on the Mayan calendars.

@table @kbd
@item g m l
Move point to a date specified by the Mayan long count calendar
(@code{calendar-goto-mayan-long-count-date}).
@item g m p t
Move point to the previous occurrence of a date specified by the Mayan
tzolkin calendar (@code{calendar-previous-tzolkin-date}).
@item g m n t
Move point to the next occurrence of a date specified by the Mayan
tzolkin calendar (@code{calendar-next-tzolkin-date}).
@item g m p h
Move point to the previous occurrence of a date specified by the Mayan
haab calendar (@code{calendar-previous-haab-date}).
@item g m n h
Move point to the next occurrence of a date specified by the Mayan
haab calendar (@code{calendar-next-haab-date}).
@item g m p c
Move point to the previous occurrence of a date specified by the Mayan
calendar round (@code{calendar-previous-calendar-round-date}).
@item g m n c
Move point to the next occurrence of a date specified by the Mayan
calendar round (@code{calendar-next-calendar-round-date}).
@end table

@cindex Mayan long count
  To understand these commands, you need to understand the Mayan calendars.
The long count is a counting of days with units

@table @asis
@item 1 kin
= 1  day
@item 1 uinal
= 20 kin
@item 1 tun
= 18 uinal
@item 1 katun
= 20 tun
@item 1 baktun
= 20 katun
@end table

@kindex g m l (Calendar mode)
@findex calendar-goto-mayan-long-count-date
@noindent
Thus, the long count date 12.16.11.16.6 means 12 baktun, 16 katun, 11
tun, 16 uinal, and 6 kin.  The Emacs calendar can handle Mayan long
count dates as early as 7.17.18.13.1, but no earlier.  When you use the
@kbd{g m l} command, type the Mayan long count date with the baktun,
katun, tun, uinal, and kin separated by periods.

@kindex g m p t (Calendar mode)
@findex calendar-previous-tzolkin-date
@kindex g m n t (Calendar mode)
@findex calendar-next-tzolkin-date
@cindex Mayan tzolkin calendar
  The Mayan tzolkin calendar is a cycle of 260 days formed by a pair of
independent cycles of 13 and 20 days.  Like the haab cycle, this cycle
repeats endlessly, and you can go backward and forward to the previous
or next (respectively) point in the cycle.  When you type @kbd{g m p t},
Emacs asks you for a tzolkin date and moves point to the
previous occurrence of that date; type @kbd{g m n t} to go to the next
occurrence.

@kindex g m p h (Calendar mode)
@findex calendar-previous-haab-date
@kindex g m n h (Calendar mode)
@findex calendar-next-haab-date
@cindex Mayan haab calendar
  The Mayan haab calendar is a cycle of 365 days arranged as 18 months
of 20 days each, followed a 5-day monthless period.  Since this cycle
repeats endlessly, Emacs lets you go backward and forward to the
previous or next (respectively) point in the cycle.  Type @kbd{g m p h}
to go to the previous haab date; Emacs asks you for a haab date and
moves point to the previous occurrence of that date.  Similarly,
type @kbd{g m n h} to go to the next haab date.

@kindex g m p c (Calendar mode)
@findex calendar-previous-calendar-round-date
@kindex g m n c (Calendar mode)
@findex calendar-next-calendar-round-date
@cindex Mayan calendar round
  The Maya also used the combination of the tzolkin date and the haab
date.  This combination is a cycle of about 52 years called a
@emph{calendar round}.  If you type @kbd{g m p c}, Emacs asks you for
both a haab and a tzolkin date and then moves point to the previous
occurrence of that combination.  Use @kbd{g m p c} to move point to the
next occurrence.  Emacs signals an error if the haab/tzolkin date you
have typed cannot occur.

  Emacs uses strict completion (@pxref{Completion}) whenever it asks you
to type a Mayan name, so you don't have to worry about spelling.

@node Diary, Calendar Customization, Other Calendars, Calendar/Diary
@subsection The Diary
@cindex diary

  Associated with the Emacs calendar is a diary that keeps track of
appointments or other events on a daily basis.  To use the diary
feature, you must first create a @dfn{diary file} containing a list of
events and their dates.  Then Emacs can automatically pick out and
display the events for today, for the immediate future, or for any
specified date.@refill

  By default, Emacs expects your diary file to be named @file{~/diary}.
It uses the same format as the @code{calendar} utility.  A sample
@file{~/diary} file is:

@example
12/22/1988 Twentieth wedding anniversary!!
&1/1. Happy New Year!
10/22 Ruth's birthday.
* 21, *: Payday
Tuesday--weekly meeting with grad students at 10am
         Supowit, Shen, Bitner, and Kapoor to attend.
1/13/89 Friday the thirteenth!!
&thu 4pm squash game with Lloyd.
mar 16 Dad's birthday
April 15, 1989 Income tax due.
&* 15 time cards due.
@end example

  Although you probably will start by creating a diary manually, Emacs
provides a number of commands to let you view, add, and change diary
entries.  You can also share diary entries with other users
(@pxref{Included Diary Files}).

@menu
* Diary Commands::         Viewing diary entries and associated calendar dates.
* Format of Diary File::   Entering events in your diary.
* Special Diary Entries::  Anniversaries, blocks of dates, cyclic entries, etc.
@end menu

@node Diary Commands, Format of Diary File, Diary, Diary
@subsection Commands Displaying Diary Entries

  Once you have created a @file{~/diary} file, you can view it within
Calendar mode.  You can also view today's events independently of
Calendar mode.

@table @kbd
@item d
Display any diary entries for the selected date
(@code{view-diary-entries}).
@item s
Display entire diary file (@code{show-all-diary-entries}).
@item m
Mark all visible dates that have diary entries
(@code{mark-diary-entries}).
@item u
Unmark calendar window (@code{calendar-unmark}).
@item M-x print-diary-entries
Print a hard copy of the diary display as it appears.
@item M-x diary
Display any diary entries for today's date.
@end table

@kindex d (Calendar mode)
@findex view-diary-entries
  Displaying the diary entries with @kbd{d} shows in a separate window the
diary entries for the date indicated by point in the calendar window.  The
mode line of the new window shows the date of the diary entries and any
holidays that fall on that date.

  If you specify a numeric argument with @kbd{d}, then all the diary
entries for that many successive days are shown.  Thus, @kbd{2 d}
displays all the entries for the selected date and for the following
day.

@kindex m (Calendar mode)
@findex mark-diary-entries
@kindex u (Calendar mode)
@findex calendar-unmark
  To get a broader overview of which days are mentioned in the diary, use
the @kbd{m} command to mark those days in the calendar window.  The marks
appear next to the dates to which they apply.  The @kbd{m} command affects
the dates currently visible and, if you scroll the calendar, newly visible
dates as well.  The @kbd{u} command deletes all diary marks (and all
holiday marks too; @pxref{Holidays}), not only in the dates currently
visible, but dates that become visible when you scroll the calendar.

@kindex s (Calendar mode)
@findex show-all-diary-entries
  For more detailed information, use the @kbd{s} command, which displays
the entire diary file.

  Display of selected diary entries uses the selective display feature,
the same feature that Outline mode uses to show part of an outline
(@pxref{Outline Mode}).  This involves hiding the diary entries that are
not relevant, by changing the preceding newline into an ASCII control-m
(code 015).  The hidden lines are part of the buffer's text, but they
are invisible; they don't appear on the screen.  When you save the diary
file, the control-m characters are saved as newlines; thus, the
invisible lines become ordinary lines in the file.

@findex print-diary-entries
  Because the diary buffer as you see it is an illusion, simply printing
the contents does not print what you see on your screen.  So there is a
special command to print a hard copy of the buffer @emph{as it appears};
this command is @kbd{M-x print-diary-entries}.  It sends the data
directly to the printer.  You can customize it like @code{lpr-region}
(@pxref{Hardcopy}).

@findex diary
  The command @kbd{M-x diary} displays the diary entries for the current
date, independently of the calendar display, and optionally for the next
few days as well; the variable @code{number-of-diary-entries} specifies
how many days to include (@pxref{Customization}).

  If you put in your @file{.emacs} file:

@example
(diary)
@end example

@noindent
it automatically displays a window with the day's diary entries, when
you enter Emacs.  The mode line of the displayed window shows the date
and any holidays that fall on that date.

@node Format of Diary File, Special Diary Entries, Diary Commands, Diary
@subsection The Diary File
@cindex diary file

@vindex diary-file
  Your @dfn{diary file} is a file that records events associated with
particular dates.  The name of the diary file is specified by the variable
@code{diary-file}; @file{~/diary} is the default.  You can use the same file
for the @code{calendar} utility program, since its formats are a subset of the
ones allowed by the Emacs Calendar.

  Each entry in the file describes one event and consists of one or more
lines.  It always begins with a date specification at the left margin.
The rest of the entry is simply text to describe the event.  If the
entry has more than one line, then the lines after the first must begin
with whitespace to indicate they continue a previous entry.

  Here are some sample diary entries, illustrating different ways of
formatting a date.  The examples all show dates in American order (month, day,
year), but Calendar mode offers (day, month, year) ordering too.

@example
4/20/93  Switch-over to new tabulation system
apr. 25  Start tabulating annual results
4/30  Results for April are due
*/25  Monthly cycle finishes
Friday  Don't leave without backing up files
@end example

  The first entry appears only once, on April 20, 1993.  The second and
third appear every year on the specified dates, and the fourth uses a
wildcard (asterisk) for the month, so it appears on the 25th of every
month.  The final entry appears every week on Friday.

  You can also use just numbers to express a date, as in
@samp{@var{month}/@var{day}} or
@samp{@var{month}/@var{day}/@var{year}}.  This must be followed by a
nondigit.  In the date itself, @var{month} and @var{day} are numbers of
one or two digits.  @var{year} is a number and may be abbreviated to the
last two digits; that is, you can use @samp{11/12/1989} or
@samp{11/12/89}.

  A date may be @dfn{generic}, or partially unspecified.  Then the entry
applies to all dates that match the specification.  If the date does
not contain a year, it is generic and applies to any year.
Alternatively, @var{month}, @var{day}, or @var{year} can be a @samp{*};
this matches any month, day, or year, respectively.  Thus, a diary entry
@samp{3/*/*} matches any day in March of any year.@refill

  Dates can also have the form @samp{@var{monthname} @var{day}} or
@samp{@var{monthname} @var{day}, @var{year}}, where the month's name can
be spelled in full or abbreviated to three characters (with or without a
period).  Case is not significant.  If the date does not contain a year,
it is generic and applies to any year.  Also, @var{monthname},
@var{day}, or @var{year} can be a @samp{*} which matches any month, day,
or year, respectively.@refill

@vindex european-calendar-style
@findex european-calendar
  If you prefer the European style of writing dates---in which the day
comes before the month---type @kbd{M-x european-calendar} while in the
calendar, or set the variable @code{european-calendar-style} to @code{t}
in your @file{.emacs} file @emph{before} the calendar or diary command.
This mode interprets all dates in the diary in the European manner, and
also uses European style for displaying diary dates.  (Note that there
is no comma after the @var{monthname} in the European style.)@refill

@findex american-calendar
  To revert to the (default) American style of writing dates, type @kbd{M-x
american-calendar}.

  You can use the name of a day of the week as a generic date which
applies to any date falling on that day of the week.  You can abbreviate
the day of the week to three letters (with or without a period) or spell
it in full; it need not be capitalized.

  You can inhibit the marking of certain diary entries in the calendar
window; to do this, insert an ampersand (@samp{&}) at the beginning of
the entry, before the date.  This has no effect on display of the entry
in the diary window; it affects only marks on dates in the calendar
window.  Nonmarking entries are especially useful for generic entries
that would otherwise mark many different dates.

  Lines that do not begin with valid dates and do not continue a preceding
entry are ignored.

  If the first line of a diary entry consists only of the date or day
name with no following blanks or punctuation, then the diary window
display doesn't include that line; only the continuation lines appear.
For example:

@example
02/11/1989
      Bill B. visits Princeton today
      2pm Cognitive Studies Committee meeting
      2:30-5:30 Liz at Lawrenceville
      4:00pm Dentist appt
      7:30pm Dinner at George's
      8:00-10:00pm concert
@end example

@noindent
appears in the diary window without the date line at the beginning.
This style of entry looks neater when you display just a single day's
entries, but can cause confusion if you ask for more than one day's
entries.

  You can edit the diary entries as they appear in the window, but it is
important to remember that the buffer displayed contains the @emph{entire}
diary file, with portions of it concealed from view.  This means, for
instance, that the @kbd{C-f} (@code{forward-char}) command can put point
at what appears to be the end of the line, but what is in reality the
middle of some concealed line.  @emph{Be careful when editing the diary
entries!}  Inserting additional lines or adding/deleting characters in the
middle of a visible line cannot cause problems.  Watch out for @kbd{C-e}
(@code{end-of-line}), however; it may put you at the end of a concealed
line far from where point appears to be!  Before editing the diary, it
is best to display the entire file with @kbd{s}
(@code{show-all-diary-entries}).@refill

  While in the calendar, there are several commands to help you in making
entries to your diary.

@table @kbd
@item i d
Add a diary entry for the selected date (@code{insert-diary-entry}).
@item i w
Add a diary entry for the selected day of the week (@code{insert-weekly-diary-entry}).
@item i m
Add a diary entry for the selected day of the month (@code{insert-monthly-diary-entry}).
@item i y
Add a diary entry for the selected day of the year (@code{insert-yearly-diary-entry}).
@end table

@kindex i d (Calendar mode)
@findex insert-diary-entry
  You can make a diary entry for a specific date by moving point to that
date in the calendar window and using the @kbd{i d} command.  This
command displays the end of your diary file in another window and
inserts the date; you can then type the rest of the diary entry.

@kindex i w (Calendar mode)
@findex insert-weekly-diary-entry
  If you want to make a diary entry that applies to a specific day of
the week, move point to that day of the week (any occurrence will do)
and use the @kbd{i w} command.  This displays the end of your diary file
in another window and inserts the day-of-week as a generic date; you can
then type the rest of the diary entry.

@kindex i m (Calendar mode)
@findex insert-monthly-diary-entry
@kindex i y (Calendar mode)
@findex insert-yearly-diary-entry
  You make a monthly diary entry in the same fashion.  Move point to the
day of the month, use the @kbd{i m} command, and type the diary entry.
Similarly, you make a yearly diary entry with the @kbd{i y} command.

  All of the above commands make marking diary entries.  If you want the diary
entry to be nonmarking, give a prefix argument to the command.  For example,
@kbd{C-u i w} makes a nonmarking, weekly diary entry.

  If you modify the diary, be sure to write the file before exiting from the
calendar.

@node Special Diary Entries,, Format of Diary File, Diary
@subsection Special Diary Entries

  In addition to entries based on calendar dates, your diary file can contain
entries for regularly occurring events such as anniversaries.  These entries
are based on expressions (sexps) that Emacs evaluates as it scans the diary
file.  Such an entry is indicated by @samp{%%} at the beginning (preceded by
@samp{&} for a nonmarking entry), followed by a sexp in parentheses.  Calendar
mode offers commands to make it easier to put some of these special entries in
your diary.

@table @kbd
@item i a
Add an anniversary diary entry for the selected date (@code{insert-anniversary-diary-entry}).
@item i b
Add a block diary entry for the current region (@code{insert-block-diary-entry}).
@item i c
Add a cyclic diary entry starting at the date (@code{insert-cyclic-diary-entry}).
@end table

@kindex i a (Calendar mode)
@findex insert-anniversary-diary-entry
  If you want to make a diary entry that applies to the anniversary of a
specific date, move point to that date and use the @kbd{i a} command.
This displays the end of your diary file in another window and inserts
the anniversary description; you can then type the rest of the diary
entry.

@findex diary-anniversary
  The effect of @kbd{i a} is to add a @code{diary-anniversary} sexp to your
diary file.  You can also add one manually, for instance:

@example
%%(diary-anniversary 10 31 1948) Arthur's birthday
@end example

@noindent
This entry applies to October 31 in any year after 1948; @samp{10 31 1948}
specifies the date.  (If you are using the European calendar style, the month
and day are interchanged.)  The reason this sexp requires a beginning
year is that advanced diary functions can use it to calculate the number of
elapsed years (@pxref{Sexp Diary Entries}).@refill

@kindex i b (Calendar mode)
@findex insert-block-diary-entry
  You can make a diary entry for a block of dates by setting the mark
at the date at one end of the block, moving point to the date at the other
end of the block, and using the @kbd{i b} command.  This command
causes the end of your diary file to be displayed in another window and the
block description to be inserted; you can then type the diary entry.

@findex diary-block
  Here is such a diary entry that applies to all dates from June 24, 1990
through July 10, 1990:

@example
%%(diary-block 6 24 1990 7 10 1990) Vacation
@end example

@noindent
The @samp{6 24 1990} indicates the starting date and the @samp{7 10 1990}
indicates the stopping date.  (Again, if you are using the European calendar
style, the month and day are interchanged.)

@kindex i c (Calendar mode)
@findex insert-cyclic-diary-entry
  You can specify cyclic diary entries that repeat after a fixed
interval of days.  Move point to the starting date and use the @kbd{i c}
command.  After you specify the length of interval, this command
displays the end of your diary file in another window and inserts the
cyclic event description; you can then type the rest of the diary
entry.

  The sexp corresponding to the @kbd{i c} command looks like:

@findex diary-cyclic
@example
%%(diary-cyclic 50 3 1 1990) Renew medication
@end example

@noindent
which applies to March 1, 1990 and every 50th day following; @samp{3 1 1990}
specifies the starting date.  (If you are using the European calendar style,
the month and day are interchanged.)

  All three of the these commands make marking diary entries.  If you want the
diary entry to be nonmarking, give a numeric argument to the command.  For
example, @kbd{C-u i a} makes a nonmarking anniversary diary
entry.

  Marking sexp diary entries in the calendar is @emph{extremely}
time-consuming, since every date visible in the calendar window must be
individually checked.  So it's a good idea to make sexp diary entries
nonmarking with @samp{&}.

  One sophisticated kind of sexp, a floating diary entry, has no corresponding
command.  The floating diary entry specifies a regularly-occurring event
by offsets specified in days, weeks, and months.  It is comparable to a
crontab entry interpreted by the @code{cron} utility on Unix systems.@refill

  Here is a nonmarking, floating diary entry that applies to the last
Thursday in November:

@findex diary-float
@example
&%%(diary-float 11 4 -1) American Thanksgiving
@end example

@noindent
The 11 specifies November (the eleventh month), the 4 specifies Thursday
(the fourth day of the week, where Sunday is numbered zero), and the
@minus{}1 specifies ``last'' (1 would mean ``first'', 2 would mean
``second'', @minus{}2 would mean ``second-to-last'', and so on).  The
month can be a single month or a list of months.  Thus you could change
the 11 above to @samp{'(1 2 3)} and have the entry apply to the last
Thursday of January, February, and March.  If the month is @code{t}, the
entry applies to all months of the year.@refill

  The sexp feature of the diary allows you to specify diary entries
based on any Emacs Lisp expression.  You can use the library of built-in
functions or you can write your own functions.  The built-in functions
include the ones shown in this section, plus a few others (@pxref{Sexp
Diary Entries}).

  The generality of sexps lets you specify any diary entry that you can
describe algorithmically.  Suppose you get paid on the 21st of the month
if it is a weekday, and to the Friday before if the 21st is on a
weekend.  The diary entry

@example
&%%(let ((dayname (calendar-day-of-week date))
         (day (car (cdr date))))
      (or (and (= day 21) (memq dayname '(1 2 3 4 5)))
          (and (memq day '(19 20)) (= dayname 5)))
         ) Pay check deposited
@end example

@noindent
to just those dates.  This example illustrates how the sexp can depend
on the variable @code{date}; this variable is a list (@var{month}
@var{day} @var{year}) that gives the Gregorian date for which the diary
entries are being found.  If the value of the sexp is @code{t}, the
entry applies to that date.  If the sexp evaluates to @code{nil}, the
entry does @emph{not} apply to that date.


@node Calendar Customization,, Diary, Calendar/Diary
@subsection Customizing the Calendar and Diary

  There are many customizations that you can use to make the calendar and
diary suit your personal tastes.

@menu
* Calendar Customizing::   Defaults you can set.
* Holiday Customizing::    Defining your own holidays.
* Date Display Format::    Changing the format.
* Time Display Format::    Changing the format.
* Daylight Savings::       Changing the default.
* Diary Customizing::      Defaults you can set.
* Hebrew/Islamic Entries:: How to obtain them.
* Fancy Diary Display::    Enhancing the diary display, sorting entries.
* Included Diary Files::   Sharing a common diary file.
* Sexp Diary Entries::     Fancy things you can do.
* Appt Customizing::	   Customizing appointment reminders.
@end menu

@node Calendar Customizing
@subsubsection Customizing the Calendar
@vindex view-diary-entries-initially

  If you set the variable @code{view-diary-entries-initially} to
@code{t}, calling up the calendar automatically displays the diary
entries for the current date as well.  The diary dates appear only if
the current date is visible.  If you add both of the following lines to
your @file{.emacs} file:@refill

@example
(setq view-diary-entries-initially t)
(calendar)
@end example

@noindent
they display both the calendar and diary windows whenever you start Emacs.

@vindex view-calendar-holidays-initially
  Similarly, if you set the variable
@code{view-calendar-holidays-initially} to @code{t}, entering the
calendar automatically displays a list of holidays for the current three
month period.  The holiday list appears in a separate window.@refill

@vindex mark-diary-entries-in-calendar
  You can set the variable @code{mark-diary-entries-in-calendar} to @code{t}
in order to place a plus sign (@samp{+}) beside any dates with diary entries.
Whenever the calendar window is displayed or redisplayed, the diary entries
are automatically marked for holidays.

@vindex mark-holidays-in-calendar
  Similarly, setting the variable @code{mark-holidays-in-calendar} to
@code{t} places an asterisk (@samp{*}) after all holiday dates visible
in the calendar window.

@vindex calendar-load-hook
  There are many customizations that you can make with the hooks
provided.  For example, the variable @code{calendar-load-hook}, whose
default value is @code{nil}, is a normal hook run when the calendar
package is first loaded (before actually starting to display the
calendar).

@vindex initial-calendar-window-hook
  The variable @code{initial-calendar-window-hook}, whose default value
is @code{nil}, is a normal hook run the first time the calendar window
is displayed.  The function is invoked only when you first enter
Calendar mode, not when you redisplay an existing Calendar window.  But
if you leave the calendar with the @kbd{q} command and reenter it, the
hook runs again.@refill

@vindex today-visible-calendar-hook
  The variable @code{today-visible-calendar-hook}, whose default value
is @code{nil}, is a normal hook run after the calendar buffer has been
prepared with the calendar when the current date is visible in the
window.  One use of this hook is to replace today's date with asterisks;
a function @code{calendar-star-date} is included for this purpose.  In
your @file{.emacs} file, put:@refill

@findex calendar-star-date
@example
(setq today-visible-calendar-hook 'calendar-star-date)
@end example

@noindent
Another standard hook function adds asterisks around the current date.
Here's how to use it:

@findex calendar-mark-today
@example
(setq today-visible-calendar-hook 'calendar-mark-today)
@end example

@vindex today-invisible-calendar-hook
@noindent
  A corresponding variable, @code{today-invisible-calendar-hook}, whose
default value is @code{nil}, is a normal hook run after the calendar
buffer text has been prepared, if the current date is @emph{not} visible
in the window.@refill

@node Holiday Customizing
@subsubsection Customizing the Holidays

@vindex calendar-holidays
@vindex christian-holidays
@vindex hebrew-holidays
@vindex islamic-holidays
  Emacs knows about holidays defined by entries on one of several lists.
You can customize theses lists of holidays to your own needs, adding
holidays or deleting lists of holidays.  The lists of holidays that
Emacs uses are for general holidays (@code{general-holidays}), local
holidays (@code{local-holidays}), Christian holidays
(@code{christian-holidays}), Hebrew (Jewish) holidays
(@code{hebrew-holidays}), Islamic (Moslem) holidays
(@code{islamic-holidays}), and other holidays (@code{other-holidays}).

@vindex general-holidays
  The general holidays are, by default, holidays common throughout the
United States.  To eliminate these holidays, set @code{general-holidays}
to @code{nil}.

@vindex local-holidays
  There are no default local holidays (but sites may supply some).  You
can set the variable @code{local-holidays} to any list of holidays, as
described below.

@vindex all-christian-calendar-holidays
@vindex all-hebrew-calendar-holidays
@vindex all-islamic-calendar-holidays
  By default, Emacs does not consider all the holidays of these
religions, only those commonly found in secular calendars.  For a more
extensive collection of religious holidays, you can set any (or all) of
the variables @code{all-christian-calendar-holidays},
@code{all-hebrew-calendar-holidays}, or
@code{all-islamic-calendar-holidays} to @code{t}.  If you want to
eliminate the religious holidays, set any or all of the corresponding
variables @code{christian-holidays}, @code{hebrew-holidays}, and
@code{islamic-holidays} to @code{nil}.@refill

@vindex other-holidays
  You can set the variable @code{other-holidays} to any list of
holidays.  This list, normally empty, is intended for your use.

@cindex holiday forms
  Each of the lists (@code{general-holidays}, @code{local-holidays},
@code{christian-holidays}, @code{hebrew-holidays},
@code{islamic-holidays}, and @code{other-holidays}) is a list of
@dfn{holiday forms}, each holiday form describing a holiday (or
sometimes a list of holidays).  Holiday forms may have the following
formats:

@table @code
@item (holiday-fixed @var{month} @var{day} @var{string})
A fixed date on the Gregorian calendar.  @var{month} and @var{day} are
numbers, @var{string} is the name of the holiday.

@item (holiday-float @var{month} @var{dayname} @var{k} @var{string})
The @var{k}th @var{dayname} in @var{month} on the Gregorian calendar
(@var{dayname}=0 for Sunday, and so on); negative @var{k} means count back
from the end of the month.  @var{string} is the name of the holiday.

@item (holiday-hebrew @var{month} @var{day} @var{string})
A fixed date on the Hebrew calendar.  @var{month} and @var{day} are
numbers, @var{string} is the name of the holiday.

@item (holiday-islamic @var{month} @var{day} @var{string})
A fixed date on the Islamic calendar.  @var{month} and @var{day} are
numbers, @var{string} is the name of the holiday.

@item (holiday-julian @var{month} @var{day} @var{string})
A fixed date on the Julian calendar.  @var{month} and @var{day} are
numbers, @var{string} is the name of the holiday.

@item (holiday-sexp @var{sexp} @var{string})
@var{sexp} is a Lisp expression that should use the variable @code{year}
to compute the date of a holiday, or @code{nil} if the holiday doesn't
happen this year.  The value represents the date as a list of the form
@code{(@var{month} @var{day} @var{year})}.  @var{string} is the name of
the holiday.

@item (if @var{boolean} @var{holiday-form} &optional @var{holiday-form})
A choice between two holidays based on the value of @var{boolean}.

@item (@var{function} &optional @var{args})
Dates requiring special computation; @var{args}, if any, are passed in
a list to the function @code{calendar-holiday-function-@var{function}}.
@end table

  For example, suppose you want to add Bastille Day, celebrated in
France on July 14.  You can do this by adding the following line
to your @file{.emacs} file:

@smallexample
(setq other-holidays '((holiday-fixed 7 14 "Bastille Day")))
@end smallexample

@noindent
The holiday form @code{(holiday-fixed 7 14 "Bastille Day")} specifies the
fourteenth day of the seventh month (July).

  Many holidays occur on a specific day of the week, at a specific time
of month.  Here is a holiday form describing Hurricane Supplication Day,
celebrated in the Virgin Islands on the fourth Monday in August:

@smallexample
(holiday-float 8 1 4 "Hurricane Supplication Day")
@end smallexample

@noindent
Here the 8 specifies August, the 1 specifies Monday (Sunday is 0,
Tuesday is 2, and so on), and the 4 specifies the fourth occurrence in
the month (1 specifies the first occurrence, 2 the second occurrence,
@minus{}1 the last occurrence, @minus{}2 the second-to-last occurrence, and
so on).

  You can specify holidays that occur on fixed days of the Hebrew,
Islamic, and Julian calendars too.  For example,

@smallexample
(setq other-holidays
      '((holiday-hebrew 10 2 "Last day of Hanukkah")
        (holiday-islamic 3 12 "Mohammed's Birthday")
        (holiday-julian 4 2 "Jefferson's Birthday")))
@end smallexample

@noindent
adds the last day of Hanukkah (since the Hebrew months are numbered with
1 starting from Nisan), the Islamic feast celebrating Mohammed's
birthday (since the Islamic months are numbered from 1 starting with
Muharram), and Thomas Jefferson's birthday, which is 2 April 1743 on the
Julian calendar.

  To include a holiday conditionally, use either the @samp{if} or the
@samp{sexp} form.  For example, American presidential elections occur on
the first Tuesday after the first Monday in November of years divisible
by 4:

@smallexample
(holiday-sexp (if (= 0 (% year 4))
                   (calendar-gregorian-from-absolute
                 (1+ (calendar-dayname-on-or-before
                       1 (+ 6 (calendar-absolute-from-gregorian
                                (list 11 1 year))))))
              "US Presidential Election"))
@end smallexample

@noindent
or

@smallexample
(if (= 0 (% displayed-year 4))
    (fixed 11
           (extract-calendar-day
             (calendar-gregorian-from-absolute
               (1+ (calendar-dayname-on-or-before
                     1 (+ 6 (calendar-absolute-from-gregorian
                              (list 11 1 displayed-year)))))))
           "US Presidential Election"))
@end smallexample

  Some holidays just don't fit into any of these forms because special
calculations are involved in their determination.  In such cases you
must write a Lisp function to do the calculation.  To include
eclipses of the sun, for example, add @code{(eclipses)} to
@code{other-holidays} and write an Emacs Lisp function
@code{eclipses} that returns a (possibly
empty) list of the relevant Gregorian dates among the
range visible in the calendar window, with descriptive strings, like
this:

@smallexample
(((6 27 1991) "Lunar Eclipse") ((7 11 1991) "Solar Eclipse") ... )
@end smallexample

@node Date Display Format
@subsubsection Date Display Format
@vindex calendar-date-display-form

  You can customize the manner of displaying dates in the diary,
in mode lines, and in messages by setting
@code{calendar-date-display-form}.  This variable is a list of
expressions that can involve the variables @code{month}, @code{day}, and
@code{year}, all numbers in string form, and @code{monthname} and
@code{dayname}, both alphabetic strings.  In the American style, the
default value of this list is as follows:

@smallexample
((if dayname (concat dayname ", ")) monthname " " day ", " year)
@end smallexample

@noindent
while in the European style this value is the default:

@smallexample
((if dayname (concat dayname ", ")) day " " monthname " " year)
@end smallexample

The ISO standard date representation is this:

@smallexample
(year "-" month "-" day)
@end smallexample

@noindent
This specifies a typical American format:

@smallexample
(month "/" day "/" (substring year -2))
@end smallexample

@node Time Display Format
@subsubsection Time Display Format
@vindex calendar-time-display-form

  In the calendar, diary, and related buffers, Emacs displays times of
day in the conventional American style with the hours from 1 through 12,
minutes, and either @samp{am} or @samp{pm}.  If you prefer the
``military'' (European) style of writing times---in which the hours go
from 00 to 23---you can alter the variable
@code{calendar-time-display-form}.  This variable is a list of
expressions that can involve the variables @code{12-hours},
@code{24-hours}, and @code{minutes}, all numbers in string form, and
@code{am-pm} and @code{time-zone}, both alphabetic strings.  The default
definition of @code{calendar-time-display-form} is as follows:

@smallexample
(12-hours ":" minutes am-pm
          (if time-zone " (") time-zone (if time-zone ")"))
@end smallexample

  Setting @code{calendar-time-display-form} to

@smallexample
(24-hours ":" minutes
          (if time-zone " (") time-zone (if time-zone ")"))
@end smallexample

@noindent
gives military-style times like @samp{21:07 (UT)} if time zone names are
defined, and times like @samp{21:07} if they are not.

@node Daylight Savings
@subsubsection Daylight Savings Time
@cindex daylight savings time

  Emacs understands the difference between standard time and daylight
savings time---the times given for sunrise, sunset, solstices,
equinoxes, and the phases of the moon take that into account.  The rules
for daylight savings time vary from place to place and have also varied
historically from year to year.  To do the job properly, Emacs needs to
know which rules to use.

  Some operating systems keep track of the rules that apply to the place
where you are; on these systems, Emacs gets the information it needs
from the system automatically.  If some or all of this information is
missing, Emacs fills in the gaps with the rules currently used in
Cambridge, Massachusetts.  If the default choice of rules is not
appropriate for your location, you can tell Emacs the rules to use by
setting certain variables.

@vindex calendar-daylight-savings-starts
@vindex calendar-daylight-savings-ends
  These variables are @code{calendar-daylight-savings-starts} and
@code{calendar-daylight-savings-ends}.  Their values should be Lisp
expressions that refer to the variable @code{year}, and evaluate to the
Gregorian date on which daylight savings time starts or (respectively)
ends, in the form of a list @code{(@var{month} @var{day} @var{year})}.
The values should be @code{nil} if your area does not use daylight
savings time.

  Emacs uses these expressions to determine the starting date of
daylight savings time for the holiday list and for correcting times of
day in the solar and lunar calculations.

  The values for Cambridge, Massachusetts are as follows:

@example
@group
(calendar-nth-named-day 1 0 4 year)
(calendar-nth-named-day -1 0 10 year)
@end group
@end example

@noindent
i.e. the first 0th day (Sunday) of the fourth month (April) in
the year specified by @code{year}, and the last Sunday of the tenth month
(October) of that year.  If daylight savings time were
changed to start on October 1, you would set
@code{calendar-daylight-savings-starts} to this:

@example
(list 10 1 year)
@end example

  For a more complex example, suppose daylight savings time begins on
the first of Nisan on the Hebrew calendar.  You would set
@code{calendar-daylight-savings-starts} as follows:

@example
(calendar-gregorian-from-absolute
  (calendar-absolute-from-hebrew
    (list 1 1 (+ year 3760))))
@end example

@noindent
because Nisan is the first month in the Hebrew calendar and the Hebrew
year differs from the Gregorian year by 3760 at Nisan.

  If there is no daylight savings time at your location, or if you want
all times in standard time, set @code{calendar-daylight-savings-starts}
and @code{calendar-daylight-savings-ends} to @code{nil}.

@vindex calendar-daylight-time-offset
  This variable specifies the difference between daylight savings time and
standard time, measured in minutes.  The value for Cambridge is 60.

@vindex calendar-daylight-savings-starts-time
@vindex calendar-daylight-savings-ends-time
  These variables specify is the number of minutes after midnight local time
when the transition to and from daylight savings time should occur.  For
Cambridge, both variables' values are 120.

@node Diary Customizing
@subsubsection Customizing the Diary

@vindex holidays-in-diary-buffer
  Ordinarily, the mode line of the diary buffer window indicates any
holidays that fall on the date of the diary entries.  The process of
checking for holidays can take several seconds, so including holiday
information delays the display of the diary buffer noticeably.  If you'd
prefer to have a faster display of the diary buffer but without the
holiday information, set the variable @code{holidays-in-diary-buffer} to
@code{nil}.@refill

@vindex number-of-diary-entries
  The variable @code{number-of-diary-entries} controls the number of
days of diary entries to be displayed at one time.  It affects the
initial display when @code{view-diary-entries-initially} is @code{t}, as
well as the command @kbd{M-x diary}.  For example, the default value is
1, which says to display only the current day's diary entries.  If the
value is 2, both the current day's and the next day's entries are
displayed.  The value can also be a vector of seven elements: if the
value is @code{[0 2 2 2 2 4 1]} then no diary entries appear on Sunday,
the current date's and the next day's diary entries appear Monday
through Thursday, Friday through Monday's entries appear on Friday,
while on Saturday only that day's entries appear.

@vindex print-diary-entries-hook
@findex print-diary-entries
  The variable @code{print-diary-entries-hook} is a normal hook run
after preparation of a temporary buffer containing just the diary
entries currently visible in the diary buffer.  (The other, irrelevant
diary entries are really absent from the temporary buffer; in the diary
buffer, they are merely hidden.)  The default value of this hook does
the printing with the command @code{lpr-buffer}.  If you want to use a
different command to do the printing, just change the value of this
hook.  Other uses might include, for example, rearranging the lines into
order by day and time.

@vindex diary-date-forms
  You can customize the form of dates in your diary file, if neither the
standard American nor European styles suits your needs, by setting the
variable @code{diary-date-forms}.  This variable is a list of forms of
dates recognized in the diary file.  Each form is a list of regular
expressions (@pxref{Regexps}) and the variables @code{month},
@code{day}, @code{year}, @code{monthname}, and @code{dayname}.  The
variable @code{monthname} matches the name of the month, capitalized or
not, or its three-letter abbreviation, followed by a period or not; it
matches @samp{*}.  Similarly, @code{dayname} matches the name of the
day, capitalized or not, or its three-letter abbreviation, followed by a
period or not.  The variables @code{month}, @code{day}, and @code{year}
match those numerical values, preceded by arbitrarily many zeros; they
also match @samp{*}.  The default value of @code{diary-date-forms} in
the American style is

@example
((month "/" day "[^/0-9]")
 (month "/" day "/" year "[^0-9]")
 (monthname " *" day "[^,0-9]")
 (monthname " *" day ", *" year "[^0-9]")
 (dayname "\\W"))
@end example

@noindent
Emacs matches of the diary entries with the date forms is done with the
standard syntax table from Fundamental mode
(@pxref{Syntax Tables,,,lispref,XEmacs Lisp Reference Manual}),
but with the @samp{*} changed so that it is a word constituent.@refill

  The forms on the list must be @emph{mutually exclusive} and must not
match any portion of the diary entry itself, just the date.  If, to be
mutually exclusive, the pattern must match a portion of the diary entry
itself, the first element of the form @emph{must} be @code{backup}.
This causes the date recognizer to back up to the beginning of the
current word of the diary entry.  Even if you use @code{backup}, the
form must absolutely not match more than a portion of the first word of
the diary entry.  The default value of @code{diary-date-forms} in the
European style is this list:

@example
((day "/" month "[^/0-9]")
 (day "/" month "/" year "[^0-9]")
 (backup day " *" monthname "\\W+\\<[^*0-9]")
 (day " *" monthname " *" year "[^0-9]")
 (dayname "\\W"))
@end example

@noindent
Notice the use of @code{backup} in the middle form because part of the
diary entry must be matched to distinguish this form from the following one.

@node Hebrew/Islamic Entries
@subsubsection Hebrew- and Islamic-Date Diary Entries

  Your diary file can have entries based on Hebrew or Islamic dates, as
well as entries based on our usual Gregorian calendar.  However, because
the processing of such entries is time-consuming and most people don't
need them, you must customize the processing of your diary file to
specify that you want such entries recognized.  If you want Hebrew-date
diary entries, for example, you must include these lines in your
@file{.emacs} file:

@vindex nongregorian-diary-listing-hook
@vindex nongregorian-diary-marking-hook
@findex list-hebrew-diary-entries
@findex mark-hebrew-diary-entries
@smallexample
(setq nongregorian-diary-listing-hook 'list-hebrew-diary-entries)
(setq nongregorian-diary-marking-hook 'mark-hebrew-diary-entries)
@end smallexample

@noindent
If you want Islamic-date entries, include these lines in your
@file{.emacs} file:

@findex list-islamic-diary-entries
@findex mark-islamic-diary-entries
@smallexample
(setq nongregorian-diary-listing-hook 'list-islamic-diary-entries)
(setq nongregorian-diary-marking-hook 'mark-islamic-diary-entries)
@end smallexample

@noindent
If you want both Hebrew- and Islamic-date entries, include these lines:

@smallexample
(setq nongregorian-diary-listing-hook
      '(list-hebrew-diary-entries list-islamic-diary-entries))
(setq nongregorian-diary-marking-hook
      '(mark-hebrew-diary-entries mark-islamic-diary-entries))
@end smallexample

  Hebrew- and Islamic-date diary entries have the same formats as
Gregorian-date diary entries, except that the date must be preceded with
an @samp{H} for Hebrew dates and an @samp{I} for Islamic dates.
Moreover, because the Hebrew and Islamic month names are not uniquely
specified by the first three letters, you may not abbreviate them.  For
example, a diary entry for the Hebrew date Heshvan 25 could look like

@smallexample
HHeshvan 25 Happy Hebrew birthday!
@end smallexample

@noindent
and would appear in the diary for any date that corresponds to Heshvan 25
on the Hebrew calendar.  Similarly, an Islamic-date diary entry might be

@smallexample
IDhu al-Qada 25 Happy Islamic birthday!
@end smallexample

@noindent
and would appear in the diary for any date that corresponds to Dhu al-Qada 25
on the Islamic calendar.

  As with Gregorian-date diary entries, Hebrew- and Islamic-date entries
are nonmarking if they are preceded with an ampersand (@samp{&}).

  There are commands to help you in making Hebrew- and Islamic-date
entries to your diary:

@table @kbd
@item i h d
Add a diary entry for the Hebrew date corresponding to the selected date
(@code{insert-hebrew-diary-entry}).
@item i h m
Add a diary entry for the day of the Hebrew month corresponding to the
selected date (@code{insert-monthly-hebrew-diary-entry}).
@item i h y
Add a diary entry for the day of the Hebrew year corresponding to the
selected date (@code{insert-yearly-hebrew-diary-entry}).
@item i i d
Add a diary entry for the Islamic date corresponding to the selected date
(@code{insert-islamic-diary-entry}).
@item i i m
Add a diary entry for the day of the Islamic month corresponding to the
selected date (@code{insert-monthly-islamic-diary-entry}).
@item i i y
Add a diary entry for the day of the Islamic year corresponding to the
selected date (@code{insert-yearly-islamic-diary-entry}).
@end table

@findex insert-hebrew-diary-entry
@findex insert-monthly-hebrew-diary-entry
@findex insert-yearly-hebrew-diary-entry
@findex insert-islamic-diary-entry
@findex insert-monthly-islamic-diary-entry
@findex insert-yearly-islamic-diary-entry
  These commands work exactly like the corresponding commands for ordinary
diary entries: Move point to a date in the calendar window and the above
commands insert the Hebrew or Islamic date (corresponding to the date
indicated by point) at the end of your diary file and you can then type the
diary entry.  If you want the diary entry to be nonmarking, give a numeric
argument to the command.

@node Fancy Diary Display
@subsubsection Fancy Diary Display
@vindex diary-display-hook
@findex simple-diary-display

  Diary display works by preparing the diary buffer and then running the
hook @code{diary-display-hook}.  The default value of this hook hides
the irrelevant diary entries and then displays the buffer
(@code{simple-diary-display}).  However, if you specify the hook as
follows,

@cindex diary buffer
@findex fancy-diary-display
@example
(add-hook 'diary-display-hook 'fancy-diary-display)
@end example

@noindent
then fancy mode displays diary entries and holidays by copying them into
a special buffer that exists only for display.  Copying provides an
opportunity to change the displayed text to make it prettier---for
example, to sort the entries by the dates they apply to.

  As with simple diary display, you can print a hard copy of the buffer
with @code{print-diary-entries}.  To print a hard copy of a day-by-day
diary for a week by positioning point on Sunday of that week, type
@kbd{7 d} and then do @kbd{M-x print-diary-entries}.  As usual, the
inclusion of the holidays slows down the display slightly; you can speed
things up by setting the variable @code{holidays-in-diary-buffer} to
@code{nil}.

@vindex diary-list-include-blanks
  Ordinarily, the fancy diary buffer does not show days for which there are
no diary entries, even if that day is a holiday.  If you want such days to be
shown in the fancy diary buffer, set the variable
@code{diary-list-include-blanks} to @code{t}.@refill

@cindex sorting diary entries
  If you use the fancy diary display, you can use the normal hook
@code{list-diary-entries-hook} to sort each day's diary entries by their
time of day.  Add this line to your @file{.emacs} file:

@findex sort-diary-entries
@example
(add-hook 'list-diary-entries-hook 'sort-diary-entries)
@end example

@noindent
For each day, this sorts diary entries that begin with a recognizable
time of day according to their times.  Diary entries without times come
first within each day.

@node Included Diary Files
@subsubsection Included Diary Files

  If you use the fancy diary display, you can have diary entries from other
files included with your own by an ``include'' mechanism.  This facility makes
possible the sharing of common diary files among groups of users.  Lines in
the diary file of this form:

@smallexample
#include "@var{filename}"
@end smallexample

@noindent
includes the diary entries from the file @var{filename} in the fancy
diary buffer (because the ordinary diary buffer is just the buffer
associated with your diary file, you cannot use the include mechanism
unless you use the fancy diary buffer).  The include mechanism is
recursive, by the way, so that included files can include other files,
and so on; you must be careful not to have a cycle of inclusions, of
course.  To enable the include facility, add lines as follows to your
@file{.emacs} file:

@vindex list-diary-entries-hook
@vindex mark-diary-entries-hook
@findex include-other-diary-files
@findex mark-included-diary-files
@smallexample
(add-hook 'list-diary-entries-hook 'include-other-diary-files)
(add-hook 'mark-diary-entries-hook 'mark-included-diary-files)
@end smallexample

@node Sexp Diary Entries
@subsubsection Sexp Entries and the Fancy Diary Display
@cindex sexp diary entries

  Sexp diary entries allow you to do more than just have complicated
conditions under which a diary entry applies.  If you use the fancy
diary display, sexp entries can generate the text of the entry depending
on the date itself.  For example, an anniversary diary entry can insert
the number of years since the anniversary date into the text of the
diary entry.  Thus the @samp{%d} in this dairy entry:

@findex diary-anniversary
@smallexample
%%(diary-anniversary 10 31 1948) Arthur's birthday (%d years old)
@end smallexample

@noindent
gets replaced by the age, so on October 31, 1990 the entry appears in
the fancy diary buffer like this:

@smallexample
Arthur's birthday (42 years old)
@end smallexample

@noindent
If the diary file instead contains this entry:

@smallexample
%%(diary-anniversary 10 31 1948) Arthur's %d%s birthday
@end smallexample

@noindent
the entry in the fancy diary buffer for October 31, 1990 appears like this:

@smallexample
Arthur's 42nd birthday
@end smallexample

  Similarly, cyclic diary entries can interpolate the number of repetitions
that have occurred:

@findex diary-cyclic
@smallexample
%%(diary-cyclic 50 1 1 1990) Renew medication (%d%s time)
@end smallexample

@noindent
looks like this:

@smallexample
Renew medication (5th time)
@end smallexample

@noindent
in the fancy diary display on September 8, 1990.

  The generality of sexp diary entries lets you specify any diary entry
that you can describe algorithmically.  Suppose you get paid on the 21st
of the month if it is a weekday, and to the Friday before if the 21st is
on a weekend.  The diary entry

@smallexample
&%%(let ((dayname (calendar-day-of-week date))
         (day (car (cdr date))))
      (or (and (= day 21) (memq dayname '(1 2 3 4 5)))
          (and (memq day '(19 20)) (= dayname 5)))
         ) Pay check deposited
@end smallexample

@noindent
applies to just those dates.  This example illustrates how the sexp can
depend on the variable @code{date}; this variable is a list (@var{month}
@var{day} @var{year}) that gives the Gregorian date for which the diary
entries are being found.  If the value of the expression is @code{t},
the entry applies to that date.  If the expression evaluates to
@code{nil}, the entry does @emph{not} apply to that date.

  The following sexp diary entries take advantage of the ability (in the fancy
diary display) to concoct diary entries based on the date:

@findex diary-sunrise-sunset
@findex diary-phases-of-moon
@findex diary-day-of-year
@findex diary-iso-date
@findex diary-julian-date
@findex diary-astro-day-number
@findex diary-hebrew-date
@findex diary-islamic-date
@findex diary-french-date
@findex diary-mayan-date
@table @code
@item %%(diary-sunrise-sunset)
Make a diary entry for the local times of today's sunrise and sunset.
@item %%(diary-phases-of-moon)
Make a diary entry for the phases (quarters) of the moon.
@item %%(diary-day-of-year)
Make a diary entry with today's day number in the current year and the number
of days remaining in the current year.
@item %%(diary-iso-date)
Make a diary entry with today's equivalent ISO commercial date.
@item %%(diary-julian-date)
Make a diary entry with today's equivalent date on the Julian calendar.
@item %%(diary-astro-day-number)
Make a diary entry with today's equivalent astronomical (Julian) day number.
@item %%(diary-hebrew-date)
Make a diary entry with today's equivalent date on the Hebrew calendar.
@item %%(diary-islamic-date)
Make a diary entry with today's equivalent date on the Islamic calendar.
@item %%(diary-french-date)
Make a diary entry with today's equivalent date on the French Revolutionary
calendar.
@item %%(diary-mayan-date)
Make a diary entry with today's equivalent date on the Mayan calendar.
@end table

@noindent
Thus including the diary entry

@smallexample
&%%(diary-hebrew-date)
@end smallexample

@noindent
causes every day's diary display to contain the equivalent date on the
Hebrew calendar, if you are using the fancy diary display.  (With simple
diary display, the line @samp{&%%(diary-hebrew-date)} appears in the
diary for any date, but does nothing particularly useful.)

  There are a number of other available sexp diary entries that are important
to those who follow the Hebrew calendar:

@cindex rosh hodesh
@findex diary-rosh-hodesh
@cindex parasha, weekly
@findex diary-parasha
@cindex candle lighting times
@findex diary-sabbath-candles
@cindex omer count
@findex diary-omer
@cindex yahrzeits
@findex diary-yahrzeit
@table @code
@item %%(diary-rosh-hodesh)
Make a diary entry that tells the occurrence and ritual announcement of each
new Hebrew month.
@item %%(diary-parasha)
Make a Saturday diary entry that tells the weekly synagogue scripture reading.
@item %%(diary-sabbath-candles)
Make a Friday diary entry that tells the @emph{local time} of Sabbath
candle lighting.
@item %%(diary-omer)
Make a diary entry that gives the omer count, when appropriate.
@item %%(diary-yahrzeit @var{month} @var{day} @var{year}) @var{name}
Make a diary entry marking the anniversary of a date of death.  The date
is the @emph{Gregorian} (civil) date of death.  The diary entry appears
on the proper Hebrew calendar anniversary and on the day before.  (In
the European style, the order of the parameters is changed to @var{day},
@var{month}, @var{year}.)
@end table

@node Appt Customizing
@subsubsection Customizing Appointment Reminders

  You can specify exactly how Emacs reminds you of an appointment and
how far in advance it begins doing so.  Here are the variables that you
can set:

@vindex appt-message-warning-time
@vindex appt-audible
@vindex appt-visible
@vindex appt-display-mode-line
@vindex appt-msg-window
@vindex appt-display-duration
@table @code
@item appt-message-warning-time
The time in minutes before an appointment that the reminder begins.  The
default is 10 minutes.
@item appt-audible
If this is @code{t} (the default), Emacs rings the terminal bell for
appointment reminders.
@item appt-visible
If this is @code{t} (the default), Emacs displays the appointment
message in echo area.
@item appt-display-mode-line
If this is @code{t} (the default), Emacs displays the number of minutes
to the appointment on the mode line.
@item appt-msg-window
If this is @code{t} (the default), Emacs displays the appointment
message in another window.
@item appt-display-duration
The number of seconds an appointment message is displayed.  The default
is 5 seconds.
@end table