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INFO-DIR-SECTION XEmacs Editor
START-INFO-DIR-ENTRY
* XEmacs: (xemacs).             XEmacs Editor.
END-INFO-DIR-ENTRY

   This file documents the XEmacs editor.

   Copyright (C) 1985, 1986, 1988 Richard M. Stallman.  Copyright (C)
1991, 1992, 1993, 1994 Lucid, Inc.  Copyright (C) 1993, 1994 Sun
Microsystems, Inc.  Copyright (C) 1995 Amdahl Corporation.

   Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

   Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided also
that the sections entitled "The GNU Manifesto", "Distribution" and "GNU
General Public License" are included exactly as in the original, and
provided that the entire resulting derived work is distributed under the
terms of a permission notice identical to this one.

   Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that the sections entitled "The GNU Manifesto",
"Distribution" and "GNU General Public License" may be included in a
translation approved by the author instead of in the original English.

\1f
File: xemacs.info,  Node: To Other Calendar,  Next: From Other Calendar,  Prev: Calendar Systems,  Up: Other Calendars

Converting To Other Calendars
=============================

   The following commands describe the selected date (the date at point)
in various other calendar systems:

`Button2  Other Calendars'
     Display the date that you click on, expressed in various other
     calendars.

`p c'
     Display ISO commercial calendar equivalent for selected day
     (`calendar-print-iso-date').

`p j'
     Display Julian date for selected day
     (`calendar-print-julian-date').

`p a'
     Display astronomical (Julian) day number for selected day
     (`calendar-print-astro-day-number').

`p h'
     Display Hebrew date for selected day
     (`calendar-print-hebrew-date').

`p i'
     Display Islamic date for selected day
     (`calendar-print-islamic-date').

`p f'
     Display French Revolutionary date for selected day
     (`calendar-print-french-date').

`p C'
     Display Chinese date for selected day
     (`calendar-print-chinese-date').

`p k'
     Display Coptic date for selected day
     (`calendar-print-coptic-date').

`p e'
     Display Ethiopic date for selected day
     (`calendar-print-ethiopic-date').

`p p'
     Display Persian date for selected day
     (`calendar-print-persian-date').

`p m'
     Display Mayan date for selected day (`calendar-print-mayan-date').

   If you are using X, the easiest way to translate a date into other
calendars is to click on it with `Button2', then choose `Other
Calendars' from the menu that appears.  This displays the equivalent
forms of the date in all the calendars Emacs understands, in the form of
a menu.  (Choosing an alternative from this menu doesn't actually do
anything--the menu is used only for display.)

   Put point on the desired date of the Gregorian calendar, then type
the appropriate keys.  The `p' is a mnemonic for "print" since Emacs
"prints" the equivalent date in the echo area.

\1f
File: xemacs.info,  Node: From Other Calendar,  Next: Mayan Calendar,  Prev: To Other Calendar,  Up: Other Calendars

Converting From Other Calendars
===============================

   You can use the other supported calendars to specify a date to move
to.  This section describes the commands for doing this using calendars
other than Mayan; for the Mayan calendar, see the following section.

`g c'
     Move to a date specified in the ISO commercial calendar
     (`calendar-goto-iso-date').

`g j'
     Move to a date specified in the Julian calendar
     (`calendar-goto-julian-date').

`g a'
     Move to a date specified in astronomical (Julian) day number
     (`calendar-goto-astro-day-number').

`g h'
     Move to a date specified in the Hebrew calendar
     (`calendar-goto-hebrew-date').

`g i'
     Move to a date specified in the Islamic calendar
     (`calendar-goto-islamic-date').

`g f'
     Move to a date specified in the French Revolutionary calendar
     (`calendar-goto-french-date').

`g C'
     Move to a date specified in the Chinese calendar
     (`calendar-goto-chinese-date').

`g p'
     Move to a date specified in the Persian calendar
     (`calendar-goto-persian-date').

`g k'
     Move to a date specified in the Coptic calendar
     (`calendar-goto-coptic-date').

`g e'
     Move to a date specified in the Ethiopic calendar
     (`calendar-goto-ethiopic-date').

   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
(*note 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.

   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 `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.

\1f
File: xemacs.info,  Node: Mayan Calendar,  Next: Diary,  Prev: From Other Calendar,  Up: Other Calendars

Converting from the Mayan Calendar
----------------------------------

   Here are the commands to select dates based on the Mayan calendar:

`g m l'
     Move to a date specified by the long count calendar
     (`calendar-goto-mayan-long-count-date').

`g m n t'
     Move to the next occurrence of a place in the tzolkin calendar
     (`calendar-next-tzolkin-date').

`g m p t'
     Move to the previous occurrence of a place in the tzolkin calendar
     (`calendar-previous-tzolkin-date').

`g m n h'
     Move to the next occurrence of a place in the haab calendar
     (`calendar-next-haab-date').

`g m p h'
     Move to the previous occurrence of a place in the haab calendar
     (`calendar-previous-haab-date').

`g m n c'
     Move to the next occurrence of a place in the calendar round
     (`calendar-next-calendar-round-date').

`g m p c'
     Move to the previous occurrence of a place in the calendar round
     (`calendar-previous-calendar-round-date').

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

     1 kin = 1 day   1 uinal = 20 kin   1 tun = 18 uinal
     1 katun = 20 tun   1 baktun = 20 katun

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
`g m l' command, type the Mayan long count date with the baktun, katun,
tun, uinal, and kin separated by periods.

   The Mayan tzolkin calendar is a cycle of 260 days formed by a pair of
independent cycles of 13 and 20 days.  Since this cycle repeats
endlessly, Emacs provides commands to move backward and forward to the
previous or next point in the cycle.  Type `g m p t' to go to the
previous tzolkin date; Emacs asks you for a tzolkin date and moves point
to the previous occurrence of that date.  Similarly, type `g m n t' to
go to the next occurrence of a tzolkin date.

   The Mayan haab calendar is a cycle of 365 days arranged as 18 months
of 20 days each, followed a 5-day monthless period.  Like the tzolkin
cycle, this cycle repeats endlessly, and there are commands to move
backward and forward to the previous or next point in the cycle.  Type
`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 `g m n h' to go to the next occurrence of a haab date.

   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 _calendar
round_.  If you type `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 `g m n c' to move point to the next occurrence of a
combination.  These commands signal an error if the haab/tzolkin date
combination you have typed is impossible.

   Emacs uses strict completion (*note Completion::) whenever it asks
you to type a Mayan name, so you don't have to worry about spelling.

\1f
File: xemacs.info,  Node: Diary,  Next: Calendar Customization,  Prev: Mayan Calendar,  Up: Calendar/Diary

The Diary
---------

   The Emacs diary keeps track of appointments or other events on a
daily basis, in conjunction with the calendar.  To use the diary
feature, you must first create a "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.

   By default, Emacs uses `~/diary' as the diary file.  This is the
same file that the `calendar' utility uses.  A sample `~/diary' file is:

     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.

This example uses extra spaces to align the event descriptions of most
of the entries.  Such formatting is purely a matter of taste.

   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 (*note
Included Diary Files::).

* Menu:

* Diary Commands::         Viewing diary entries and associated calendar dates.
* Format of Diary File::   Entering events in your diary.
* Date Formats::           Various ways you can specify dates.
* Adding to Diary::        Commands to create diary entries.
* Special Diary Entries::  Anniversaries, blocks of dates, cyclic entries, etc.

\1f
File: xemacs.info,  Node: Diary Commands,  Next: Format of Diary File,  Prev: Diary,  Up: Diary

Commands Displaying Diary Entries
---------------------------------

   Once you have created a `~/diary' file, you can use the calendar to
view it.  You can also view today's events outside of Calendar mode.

`d'
     Display all diary entries for the selected date
     (`view-diary-entries').

`Button2 Diary'
     Display all diary entries for the date you click on.

`s'
     Display the entire diary file (`show-all-diary-entries').

`m'
     Mark all visible dates that have diary entries
     (`mark-diary-entries').

`u'
     Unmark the calendar window (`calendar-unmark').

`M-x print-diary-entries'
     Print hard copy of the diary display as it appears.

`M-x diary'
     Display all diary entries for today's date.

`M-x diary-mail-entries'
     Mail yourself email reminders about upcoming diary entries.

   Displaying the diary entries with `d' shows in a separate window the
diary entries for the selected date in the calendar.  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 `d', it
shows all the diary entries for that many successive days.  Thus, `2 d'
displays all the entries for the selected date and for the following
day.

   Another way to display the diary entries for a date is to click
`Button2' on the date, and then choose `Diary' from the menu that
appears.

   To get a broader view of which days are mentioned in the diary, use
the `m' command.  This displays the dates that have diary entries in a
different face (or places a `+' after these dates, if display with
multiple faces is not available).  The command applies both to the
currently visible months and to other months that subsequently become
visible by scrolling.  To turn marking off and erase the current marks,
type `u', which also turns off holiday marks (*note Holidays::).

   To see the full diary file, rather than just some of the entries, use
the `s' command.

   Display of selected diary entries uses the selective display feature
to hide entries that don't apply.

   The diary buffer as you see it is an illusion, so simply printing the
buffer does not print what you see on your screen.  There is a special
command to print hard copy of the diary buffer _as it appears_; this
command is `M-x print-diary-entries'.  It sends the data directly to
the printer.  You can customize it like `lpr-region' (*note Hardcopy::).

   The command `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 `number-of-diary-entries' specifies how
many days to include (*note Customization::).

   If you put `(diary)' in your `.emacs' file, this 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.

   Many users like to receive notice of events in their diary as email.
To send such mail to yourself, use the command `M-x
diary-mail-entries'.  A prefix argument specifies how many days
(starting with today) to check; otherwise, the variable
`diary-mail-days' says how many days.

\1f
File: xemacs.info,  Node: Format of Diary File,  Next: Date Formats,  Prev: Diary Commands,  Up: Diary

The Diary File
--------------

   Your "diary file" is a file that records events associated with
particular dates.  The name of the diary file is specified by the
variable `diary-file'; `~/diary' is the default.  The `calendar'
utility program supports a subset of the format allowed by the Emacs
diary facilities, so you can use that utility to view the diary file,
with reasonable results aside from the entries it cannot understand.

   Each entry in the diary file describes one event and consists of one
or more lines.  An entry 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.  Lines that do not begin with valid dates and do not continue a
preceding entry are ignored.

   You can inhibit the marking of certain diary entries in the calendar
window; to do this, insert an ampersand (`&') 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.

   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, this entry:

     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

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 _entire_
diary file, with portions of it concealed from view.  This means, for
instance, that the `C-f' (`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.

   _Be careful when editing the diary entries!_  Inserting additional
lines or adding/deleting characters in the middle of a visible line
cannot cause problems, but editing at the end of a line may not do what
you expect.  Deleting a line may delete other invisible entries that
follow it.  Before editing the diary, it is best to display the entire
file with `s' (`show-all-diary-entries').

\1f
File: xemacs.info,  Node: Date Formats,  Next: Adding to Diary,  Prev: Format of Diary File,  Up: Diary

Date Formats
------------

   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 supports European order (day,
month, year) as an option.

     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

   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 use just numbers to express a date, as in `MONTH/DAY' or
`MONTH/DAY/YEAR'.  This must be followed by a nondigit.  In the date
itself, MONTH and DAY are numbers of one or two digits.  The optional
YEAR is also a number, and may be abbreviated to the last two digits;
that is, you can use `11/12/1989' or `11/12/89'.

   Dates can also have the form `MONTHNAME DAY' or `MONTHNAME DAY,
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.

   A date may be "generic"; that is, 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, MONTH, DAY, or YEAR can be a `*'; this matches any
month, day, or year, respectively.  Thus, a diary entry `3/*/*' matches
any day in March of any year; so does `march *'.

   If you prefer the European style of writing dates--in which the day
comes before the month--type `M-x european-calendar' while in the
calendar, or set the variable `european-calendar-style' to `t' _before_
using any 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
MONTHNAME in the European style.)  To go back to the (default) American
style of writing dates, type `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; case is not significant.

\1f
File: xemacs.info,  Node: Adding to Diary,  Next: Special Diary Entries,  Prev: Date Formats,  Up: Diary

Commands to Add to the Diary
----------------------------

   While in the calendar, there are several commands to create diary
entries:

`i d'
     Add a diary entry for the selected date (`insert-diary-entry').

`i w'
     Add a diary entry for the selected day of the week
     (`insert-weekly-diary-entry').

`i m'
     Add a diary entry for the selected day of the month
     (`insert-monthly-diary-entry').

`i y'
     Add a diary entry for the selected day of the year
     (`insert-yearly-diary-entry').

   You can make a diary entry for a specific date by selecting that date
in the calendar window and typing the `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.

   If you want to make a diary entry that applies to a specific day of
the week, select that day of the week (any occurrence will do) and type
`i w'.  This inserts the day-of-week as a generic date; you can then
type the rest of the diary entry.  You can make a monthly diary entry in
the same fashion.  Select the day of the month, use the `i m' command,
and type rest of the entry.  Similarly, you can insert a yearly diary
entry with the `i y' command.

   All of the above commands make marking diary entries by default.  To
make a nonmarking diary entry, give a numeric argument to the command.
For example, `C-u i w' makes a nonmarking weekly diary entry.

   When you modify the diary file, be sure to save the file before
exiting Emacs.

\1f
File: xemacs.info,  Node: Special Diary Entries,  Prev: Adding to Diary,  Up: Diary

Special Diary Entries
---------------------

   In addition to entries based on calendar dates, the diary file can
contain "sexp entries" for regular events such as anniversaries.  These
entries are based on Lisp expressions (sexps) that Emacs evaluates as
it scans the diary file.  Instead of a date, a sexp entry contains `%%'
followed by a Lisp expression which must begin and end with
parentheses.  The Lisp expression determines which dates the entry
applies to.

   Calendar mode provides commands to insert certain commonly used sexp
entries:

`i a'
     Add an anniversary diary entry for the selected date
     (`insert-anniversary-diary-entry').

`i b'
     Add a block diary entry for the current region
     (`insert-block-diary-entry').

`i c'
     Add a cyclic diary entry starting at the date
     (`insert-cyclic-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 `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. The entry looks like this:

   The effect of `i a' is to add a `diary-anniversary' sexp to your
diary file.  You can also add one manually, for instance:

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

This entry applies to October 31 in any year after 1948; `10 31 1948'
specifies the date.  (If you are using the European calendar style, the
month and day are interchanged.)  The reason this expression requires a
beginning year is that advanced diary functions can use it to calculate
the number of elapsed years.

   A "block" diary entry applies to a specified range of consecutive
dates.  Here is a block diary entry that applies to all dates from June
24, 1990 through July 10, 1990:

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

The `6 24 1990' indicates the starting date and the `7 10 1990'
indicates the stopping date.  (Again, if you are using the European
calendar style, the month and day are interchanged.)

   To insert a block entry, place point and the mark on the two dates
that begin and end the range, and type `i b'.  This command displays
the end of your diary file in another window and inserts the block
description; you can then type the diary entry.

   "Cyclic" diary entries repeat after a fixed interval of days.  To
create one, select the starting date and use the `i c' command.  The
command prompts for the length of interval, then inserts the entry,
which looks like this:

     %%(diary-cyclic 50 3 1 1990) Renew medication

This entry applies to March 1, 1990 and every 50th day following; `3 1
1990' specifies the starting date.  (If you are using the European
calendar style, the month and day are interchanged.)

   All three of these commands make marking diary entries.  To insert a
nonmarking entry, give a numeric argument to the command.  For example,
`C-u i a' makes a nonmarking anniversary diary entry.

   Marking sexp diary entries in the calendar is _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 `&') when possible.

   Another sophisticated kind of sexp entry, a "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 `cron' utility.  Here is a nonmarking, floating diary entry that
applies to the last Thursday in November:

     &%%(diary-float 11 4 -1) American Thanksgiving

The 11 specifies November (the eleventh month), the 4 specifies Thursday
(the fourth day of the week, where Sunday is numbered zero), and the -1
specifies "last" (1 would mean "first", 2 would mean "second", -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 `'(1 2 3)' and
have the entry apply to the last Thursday of January, February, and
March.  If the month is `t', the entry applies to all months of the
year.

   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 (*note 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

     &%%(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

to just those dates.  This example illustrates how the sexp can depend
on the variable `date'; this variable is a list (MONTH DAY YEAR) that
gives the Gregorian date for which the diary entries are being found.
If the value of the sexp is `t', the entry applies to that date.  If
the sexp evaluates to `nil', the entry does _not_ apply to that date.

\1f
File: xemacs.info,  Node: Calendar Customization,  Prev: Diary,  Up: Calendar/Diary

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.

\1f
File: xemacs.info,  Node: Calendar Customizing,  Next: Holiday Customizing,  Up: Calendar Customization

Customizing the Calendar
........................

   If you set the variable `view-diary-entries-initially' to `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
`.emacs' file:

     (setq view-diary-entries-initially t)
     (calendar)

this displays both the calendar and diary windows whenever you start
Emacs.

   Similarly, if you set the variable
`view-calendar-holidays-initially' to `t', entering the calendar
automatically displays a list of holidays for the current three-month
period.  The holiday list appears in a separate window.

   You can set the variable `mark-diary-entries-in-calendar' to `t' in
order to mark any dates with diary entries.  This takes effect whenever
the calendar window contents are recomputed.  There are two ways of
marking these dates: by changing the face (*note Faces::), if the
display supports that, or by placing a plus sign (`+') beside the date
otherwise.

   Similarly, setting the variable `mark-holidays-in-calendar' to `t'
marks holiday dates, either with a change of face or with an asterisk
(`*').

   The variable `calendar-holiday-marker' specifies how to mark a date
as being a holiday.  Its value may be a character to insert next to the
date, or a face name to use for displaying the date.  Likewise, the
variable `diary-entry-marker' specifies how to mark a date that has
diary entries.  The calendar creates faces named `holiday-face' and
`diary-face' for these purposes; those symbols are the default values
of these variables, when Emacs supports multiple faces on your terminal.

   The variable `calendar-load-hook' is a normal hook run when the
calendar package is first loaded (before actually starting to display
the calendar).

   Starting the calendar runs the normal hook
`initial-calendar-window-hook'.  Recomputation of the calendar display
does not run this hook.  But if you leave the calendar with the `q'
command and reenter it, the hook runs again.

   The variable `today-visible-calendar-hook' 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; to do that, use the hook function
`calendar-star-date'.

     (add-hook 'today-visible-calendar-hook 'calendar-star-date)

Another standard hook function marks the current date, either by
changing its face or by adding an asterisk.  Here's how to use it:

     (add-hook 'today-visible-calendar-hook 'calendar-mark-today)

The variable `calendar-today-marker' specifies how to mark today's
date.  Its value should be a character to insert next to the date or a
face name to use for displaying the date.  A face named
`calendar-today-face' is provided for this purpose; that symbol is the
default for this variable when Emacs supports multiple faces on your
terminal.

A similar normal hook, `today-invisible-calendar-hook' is run if the
current date is _not_ visible in the window.

\1f
File: xemacs.info,  Node: Holiday Customizing,  Next: Date Display Format,  Prev: Calendar Customizing,  Up: Calendar Customization

Customizing the Holidays
........................

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

   The general holidays are, by default, holidays common throughout the
United States.  To eliminate these holidays, set `general-holidays' to
`nil'.

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

   By default, Emacs does not include all the holidays of the religions
that it knows, only those commonly found in secular calendars.  For a
more extensive collection of religious holidays, you can set any (or
all) of the variables `all-christian-calendar-holidays',
`all-hebrew-calendar-holidays', or `all-islamic-calendar-holidays' to
`t'.  If you want to eliminate the religious holidays, set any or all
of the corresponding variables `christian-holidays', `hebrew-holidays',
and `islamic-holidays' to `nil'.

   You can set the variable `other-holidays' to any list of holidays.
This list, normally empty, is intended for individual use.

   Each of the lists (`general-holidays', `local-holidays',
`christian-holidays', `hebrew-holidays', `islamic-holidays', and
`other-holidays') is a list of "holiday forms", each holiday form
describing a holiday (or sometimes a list of holidays).

   Here is a table of the possible kinds of holiday form.  Day numbers
and month numbers count starting from 1, but "dayname" numbers count
Sunday as 0.  The element STRING is always the name of the holiday, as
a string.

`(holiday-fixed MONTH DAY STRING)'
     A fixed date on the Gregorian calendar.  MONTH and DAY are
     numbers, STRING is the name of the holiday.

`(holiday-float MONTH DAYNAME K STRING)'
     The Kth DAYNAME in MONTH on the Gregorian calendar (DAYNAME=0 for
     Sunday, and so on); negative K means count back from the end of
     the month.  STRING is the name of the holiday.

`(holiday-hebrew MONTH DAY STRING)'
     A fixed date on the Hebrew calendar.  MONTH and DAY are numbers,
     STRING is the name of the holiday.

`(holiday-islamic MONTH DAY STRING)'
     A fixed date on the Islamic calendar.  MONTH and DAY are numbers,
     STRING is the name of the holiday.

`(holiday-julian MONTH DAY STRING)'
     A fixed date on the Julian calendar.  MONTH and DAY are numbers,
     STRING is the name of the holiday.

`(holiday-sexp SEXP STRING)'
     A date calculated by the Lisp expression SEXP.  The expression
     should use the variable `year' to compute and return the date of a
     holiday, or `nil' if the holiday doesn't happen this year.  The
     value of SEXP must represent the date as a list of the form
     `(MONTH DAY YEAR)'.  STRING is the name of the holiday.

`(if CONDITION HOLIDAY-FORM &optional HOLIDAY-FORM)'
     A holiday that happens only if CONDITION is true.

`(FUNCTION [ARGS])'
     A list of dates calculated by the function FUNCTION, called with
     arguments ARGS.

   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 `.emacs' file:

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

The holiday form `(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:

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

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,
-1 the last occurrence, -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,

     (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")))

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 Emacs Lisp's `if' or
the `holiday-sexp' form.  For example, American presidential elections
occur on the first Tuesday after the first Monday in November of years
divisible by 4:

     (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"))

or

     (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"))

   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,
for example, add `(eclipses)' to `other-holidays' and write an Emacs
Lisp function `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:

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

\1f
File: xemacs.info,  Node: Date Display Format,  Next: Time Display Format,  Prev: Holiday Customizing,  Up: Calendar Customization

Date Display Format
...................

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

     ((if dayname (concat dayname ", ")) monthname " " day ", " year)

while in the European style this value is the default:

     ((if dayname (concat dayname ", ")) day " " monthname " " year)

   + The ISO standard date representation is this:

     (year "-" month "-" day)

This specifies a typical American format:

     (month "/" day "/" (substring year -2))

\1f
File: xemacs.info,  Node: Time Display Format,  Next: Daylight Savings,  Prev: Date Display Format,  Up: Calendar Customization

Time Display Format
...................

   The calendar and diary by default display times of day in the
conventional American style with the hours from 1 through 12, minutes,
and either `am' or `pm'.  If you prefer the European style, also known
in the US as military, in which the hours go from 00 to 23, you can
alter the variable `calendar-time-display-form'.  This variable is a
list of expressions that can involve the variables `12-hours',
`24-hours', and `minutes', which are all numbers in string form, and
`am-pm' and `time-zone', which are both alphabetic strings.  The
default value of `calendar-time-display-form' is as follows:

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

Here is a value that provides European style times:

     (24-hours ":" minutes
               (if time-zone " (") time-zone (if time-zone ")"))

gives military-style times like `21:07 (UT)' if time zone names are
defined, and times like `21:07' if they are not.

\1f
File: xemacs.info,  Node: Daylight Savings,  Next: Diary Customizing,  Prev: Time Display Format,  Up: Calendar Customization

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 resulting rules are
not what you want, you can tell Emacs the rules to use by setting
certain variables.

   If the default choice of rules is not appropriate for your location,
you can tell Emacs the rules to use by setting the variables
`calendar-daylight-savings-starts' and
`calendar-daylight-savings-ends'.  Their values should be Lisp
expressions that refer to the variable `year', and evaluate to the
Gregorian date on which daylight savings time starts or (respectively)
ends, in the form of a list `(MONTH DAY YEAR)'.  The values should be
`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:

     (calendar-nth-named-day 1 0 4 year)
     (calendar-nth-named-day -1 0 10 year)

That is, the first 0th day (Sunday) of the fourth month (April) in the
year specified by `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 `calendar-daylight-savings-starts' to this:

     (list 10 1 year)

   For a more complex example, suppose daylight savings time begins on
the first of Nisan on the Hebrew calendar.  You should set
`calendar-daylight-savings-starts' to this value:

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

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 `calendar-daylight-savings-starts' and
`calendar-daylight-savings-ends' to `nil'.

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

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

\1f
File: xemacs.info,  Node: Diary Customizing,  Next: Hebrew/Islamic Entries,  Prev: Daylight Savings,  Up: Calendar Customization

Customizing the Diary
.....................

   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 `holidays-in-diary-buffer' to
`nil'.

   The variable `number-of-diary-entries' controls the number of days
of diary entries to be displayed at one time.  It affects the initial
display when `view-diary-entries-initially' is `t', as well as the
command `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: for example, if the value
is `[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.

   The variable `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 `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.

   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 `diary-date-forms'.  This variable is a list of patterns
for recognizing a date.  Each date pattern is a list whose elements may
be regular expressions (*note Regexps::) or the symbols `month', `day',
`year', `monthname', and `dayname'.  All these elements serve as
patterns that match certain kinds of text in the diary file.  In order
for the date pattern, as a whole, to match, all of its elements must
match consecutively.

   A regular expression in a date pattern matches in its usual fashion,
using the standard syntax table altered so that `*' is a word
constituent.

   The symbols `month', `day', `year', `monthname', and `dayname' match
the month number, day number, year number, month name, and day name of
the date being considered.  The symbols that match numbers allow
leading zeros; those that match names allow three-letter abbreviations
and capitalization.  All the symbols can match `*'; since `*' in a
diary entry means "any day", "any month", and so on, it should match
regardless of the date being considered.

   The default value of `diary-date-forms' in the American style is
this:

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

Emacs matches of the diary entries with the date forms is done with the
standard syntax table from Fundamental mode (*note Syntax Tables:
(lispref)Syntax Tables.), but with the `*' changed so that it is a word
constituent.

   The date patterns in the list must be _mutually exclusive_ and must
not match any portion of the diary entry itself, just the date and one
character of whitespace.  If, to be mutually exclusive, the pattern
must match a portion of the diary entry text--beyond the whitespace
that ends the date--then the first element of the date pattern _must_
be `backup'.  This causes the date recognizer to back up to the
beginning of the current word of the diary entry, after finishing the
match.  Even if you use `backup', the date pattern must absolutely not
match more than a portion of the first word of the diary entry.  The
default value of `diary-date-forms' in the European style is this list:

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

Notice the use of `backup' in the third pattern, because it needs to
match part of a word beyond the date itself to distinguish it from the
fourth pattern.

\1f
File: xemacs.info,  Node: Hebrew/Islamic Entries,  Next: Fancy Diary Display,  Prev: Diary Customizing,  Up: Calendar Customization

Hebrew- and Islamic-Date Diary Entries
......................................

   Your diary file can have entries based on Hebrew or Islamic dates, as
well as entries based on the world-standard Gregorian calendar.
However, because recognition of such entries is time-consuming and most
people don't use them, you must explicitly enable their use.  If you
want the diary to recognize Hebrew-date diary entries, for example, you
must do this:

     (add-hook 'nongregorian-diary-listing-hook 'list-hebrew-diary-entries)
     (add-hook 'nongregorian-diary-marking-hook 'mark-hebrew-diary-entries)

If you want Islamic-date entries, do this:

     (add-hook 'nongregorian-diary-listing-hook 'list-islamic-diary-entries)
     (add-hook 'nongregorian-diary-marking-hook 'mark-islamic-diary-entries)

   Hebrew- and Islamic-date diary entries have the same formats as
Gregorian-date diary entries, except that `H' precedes a Hebrew date
and `I' precedes an Islamic date.  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 this:

     HHeshvan 25 Happy Hebrew birthday!

and would appear in the diary for any date that corresponds to Heshvan
25 on the Hebrew calendar.  And here is  Islamic-date diary entry  that
matches Dhu al-Qada 25:

     IDhu al-Qada 25 Happy Islamic birthday!

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 (`&').

   Here is a table of commands used in the calendar to create diary
entries that match the selected date and other dates that are similar
in the Hebrew or Islamic calendar:

`i h d'
     Add a diary entry for the Hebrew date corresponding to the
     selected date (`insert-hebrew-diary-entry').

`i h m'
     Add a diary entry for the day of the Hebrew month corresponding to
     the selected date (`insert-monthly-hebrew-diary-entry').  This
     diary entry matches any date that has the same Hebrew
     day-within-month as the selected date.

`i h y'
     Add a diary entry for the day of the Hebrew year corresponding to
     the selected date (`insert-yearly-hebrew-diary-entry').  This diary
     entry matches any date which has the same Hebrew month and
     day-within-month as the selected date.

`i i d'
     Add a diary entry for the Islamic date corresponding to the
     selected date (`insert-islamic-diary-entry').

`i i m'
     Add a diary entry for the day of the Islamic month corresponding
     to the selected date (`insert-monthly-islamic-diary-entry').

`i i y'
     Add a diary entry for the day of the Islamic year corresponding to
     the selected date (`insert-yearly-islamic-diary-entry').

   These commands work much like the corresponding commands for ordinary
diary entries: they apply to the date that point is on in the calendar
window, and what they do is insert just the date portion of a diary
entry at the end of your diary file.  You must then insert the rest of
the diary entry.