(M-40132'): Unify GT-53970.

[chise/xemacs-chise.git-] / info / xemacs.info-15

This is ../info/xemacs.info, produced by makeinfo version 4.0b from
xemacs/xemacs.texi.

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: Specified Dates,  Prev: Move to Beginning or End,  Up: Calendar Motion

Particular Dates
................

   Calendar mode provides commands for moving to a particular date
specified in various ways.

`g d'
     Move point to specified date (`calendar-goto-date').

`o'
     Center calendar around specified month (`calendar-other-month').

`.'
     Move point to today's date (`calendar-goto-today').

   `g d' (`calendar-goto-date') prompts for a year, a month, and a day
of the month, and then moves 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 `1990', not `90'.

   `o' (`calendar-other-month') prompts for a month and year, then
centers the three-month calendar around that month.

   You can return to today's date with `.' (`calendar-goto-today').

\1f
File: xemacs.info,  Node: Scroll Calendar,  Next: Mark and Region,  Prev: Calendar Motion,  Up: Calendar/Diary

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.

`C-x <'
     Scroll calendar one month forward (`scroll-calendar-left').

`C-x >'
     Scroll calendar one month backward (`scroll-calendar-right').

`C-v'
`<NEXT>'
     Scroll calendar three months forward
     (`scroll-calendar-left-three-months').

`M-v'
`<PRIOR>'
     Scroll calendar three months backward
     (`scroll-calendar-right-three-months').

   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.  `C-x <' scrolls the
calendar contents one month to the left; that is, it moves the display
forward in time.  `C-x >' scrolls the contents to the right, which
moves backwards in time.

   The commands `C-v' and `M-v' scroll the calendar by an entire
"screenful"--three months--in analogy with the usual meaning of these
commands.  `C-v' makes later dates visible and `M-v' makes earlier
dates visible.  These commands take a numeric argument as a repeat
count; in particular, since `C-u' multiplies the next command by four,
typing `C-u C-v' scrolls the calendar forward by a year and typing `C-u
M-v' scrolls the calendar backward by a year.

   The function keys <NEXT> and <PRIOR> are equivalent to `C-v' and
`M-v', just as they are in other modes.

\1f
File: xemacs.info,  Node: Mark and Region,  Next: General Calendar,  Prev: Scroll Calendar,  Up: Calendar/Diary

The Mark and the Region
-----------------------

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

`C-SPC'
     Set the mark to today's date (`calendar-set-mark').

`C-@'
     The same.

`C-x C-x'
     Interchange mark and point (`calendar-exchange-point-and-mark').

`M-='
     Display the number of days in the current region
     (`calendar-count-days-region').

   You set the mark in the calendar, as in any other buffer, by using
`C-@' or `C-SPC' (`calendar-set-mark').  You return to the marked date
with the command `C-x C-x' (`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.

   To determine the number of days in the region, type `M-='
(`calendar-count-days-region').  The numbers of days printed is
_inclusive_; that is, it includes the days specified by mark and point.

   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 (*note Mark Ring::) operates exactly as in other buffers:  Emacs
remembers 16 previous locations of the mark.  To return to a marked
date, type `C-u C-SPC' (or `C-u C-@'); this is the command
`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.

\1f
File: xemacs.info,  Node: General Calendar,  Next: LaTeX Calendar,  Prev: Mark and Region,  Up: Calendar/Diary

Miscellaneous Calendar Commands
-------------------------------

`p d'
     Display day-in-year (`calendar-print-day-of-year').

`?'
     Briefly describe calendar commands (`describe-calendar-mode').

`C-c C-l'
     Regenerate the calendar window (`redraw-calendar').

`SPC'
     Scroll the next window (`scroll-other-window').

`q'
     Exit from calendar (`exit-calendar').

   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 `p d'
command (`calendar-print-day-of-year').  This displays both of those
numbers in the echo area.

   To display a brief description of the calendar commands, type `?'
(`describe-calendar-mode').  For a fuller description, type `C-h m'.

   You can use `SPC' (`scroll-other-window') to scroll the other
window.  This is handy when you display a list of holidays or diary
entries in another window.

   If the calendar window text gets corrupted, type `C-c C-l'
(`redraw-calendar') to redraw it.  (This can only happen if you use
non-Calendar-mode editing commands.)

   In Calendar mode, you can use `SPC' (`scroll-other-window') to
scroll the other window.  This is handy when you display a list of
holidays or diary entries in another window.

   To exit from the calendar, type `q' (`exit-calendar').  This buries
all buffers related to the calendar, selecting other buffers.  (If a
frame contains a dedicated calendar window, exiting from the calendar
iconifies that frame.)

\1f
File: xemacs.info,  Node: LaTeX Calendar,  Next: Holidays,  Prev: General Calendar,  Up: Calendar/Diary

LaTeX Calendar
==============

   The Calendar LaTeX commands produce a buffer of LaTeX code that
prints as a calendar.  Depending on the command you use, the printed
calendar covers the day, week, month or year that point is in.

`t m'
     Generate a one-month calendar (`cal-tex-cursor-month').

`t M'
     Generate a sideways-printing one-month calendar
     (`cal-tex-cursor-month-landscape').

`t d'
     Generate a one-day calendar (`cal-tex-cursor-day').

`t w 1'
     Generate a one-page calendar for one week (`cal-tex-cursor-week').

`t w 2'
     Generate a two-page calendar for one week (`cal-tex-cursor-week2').

`t w 3'
     Generate an ISO-style calendar for one week
     (`cal-tex-cursor-week-iso').

`t w 4'
     Generate a calendar for one Monday-starting week
     (`cal-tex-cursor-week-monday').

`t f w'
     Generate a Filofax-style two-weeks-at-a-glance calendar
     (`cal-tex-cursor-filofax-2week').

`t f W'
     Generate a Filofax-style one-week-at-a-glance calendar
     (`cal-tex-cursor-filofax-week').

`t y'
     Generate a calendar for one year (`cal-tex-cursor-year').

`t Y'
     Generate a sideways-printing calendar for one year
     (`cal-tex-cursor-year-landscape').

`t f y'
     Generate a Filofax-style calendar for one year
     (`cal-tex-cursor-filofax-year').

   Some of these commands print the calendar sideways (in "landscape
mode"), so it can be wider than it is long.  Some of them use Filofax
paper size (3.75in x 6.75in).  All of these commands accept a prefix
argument which specifies how many days, weeks, months or years to print
(starting always with the selected one).

   If the variable `cal-tex-holidays' is non-`nil' (the default), then
the printed calendars show the holidays in `calendar-holidays'.  If the
variable `cal-tex-diary' is non-`nil' (the default is `nil'), diary
entries are included also (in weekly and monthly calendars only).

\1f
File: xemacs.info,  Node: Holidays,  Next: Sunrise/Sunset,  Prev: LaTeX Calendar,  Up: Calendar/Diary

Holidays
--------

   The Emacs calendar knows about all major and many minor holidays,
and can display them.

`h'
     Display holidays for the selected date
     (`calendar-cursor-holidays').

`Button2 Holidays'
     Display any holidays for the date you click on.

`x'
     Mark holidays in the calendar window (`mark-calendar-holidays').

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

`a'
     List all holidays for the displayed three months in another window
     (`list-calendar-holidays').

`M-x holidays'
     List all holidays for three months around today's date in another
     window.

`M-x list-holidays'
     List holidays in another window for a specified range of years.

   To see if any holidays fall on a given date, position point on that
date in the calendar window and use the `h' command.  Alternatively,
click on that date with `Button2' and then choose `Holidays' from the
menu that appears.  Either way, this displays the holidays for that
date, in the echo area if they fit there, otherwise in a separate
window.

   To view the distribution of holidays for all the dates shown in the
calendar, use the `x' command.  This displays the dates that are
holidays 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 erases any diary marks (*note Diary::).

   To get even more detailed information, use the `a' command, which
displays a separate buffer containing a list of all holidays in the
current three-month range.  You can use <SPC> in the calendar window to
scroll that list.

   The command `M-x holidays' displays the list of holidays for the
current month and the preceding and succeeding months; this works even
if you don't have a calendar window.  If you want the list of holidays
centered around a different month, use `C-u M-x holidays', which
prompts for the month and year.

   The holidays known to Emacs include United States holidays and the
major Christian, Jewish, and Islamic holidays; also the solstices and
equinoxes.

   The command `M-x list-holidays' displays the list of holidays for a
range of years.  This function asks you for the starting and stopping
years, and allows you to choose all the holidays or one of several
categories of holidays.  You can use this command even if you don't have
a calendar window.

   The dates used by Emacs for holidays are based on _current
practice_, not historical fact.  Historically, for instance, the start
of daylight savings time and even its existence have varied from year to
year, but present United States law mandates that daylight savings time
begins on the first Sunday in April.  When the daylight savings rules
are set up for the United States, Emacs always uses the present
definition, even though it is wrong for some prior years.

\1f
File: xemacs.info,  Node: Sunrise/Sunset,  Next: Lunar Phases,  Prev: Holidays,  Up: Calendar/Diary

Times of Sunrise and Sunset
---------------------------

   Special calendar commands can tell you, to within a minute or two,
the times of sunrise and sunset for any date.

`S'
     Display times of sunrise and sunset for the selected date
     (`calendar-sunrise-sunset').

`Button2 Sunrise/Sunset'
     Display times of sunrise and sunset for the date you click on.

`M-x sunrise-sunset'
     Display times of sunrise and sunset for today's date.

`C-u M-x sunrise-sunset'
     Display times of sunrise and sunset for a specified date.

   Within the calendar, to display the _local times_ of sunrise and
sunset in the echo area, move point to the date you want, and type `S'.
Alternatively, click `Button2' on the date, then choose
`Sunrise/Sunset' from the menu that appears.  The command `M-x
sunrise-sunset' is available outside the calendar to display this
information for today's date or a specified date.  To specify a date
other than today, use `C-u M-x sunrise-sunset', which prompts for the
year, month, and day.

   You can display the times of sunrise and sunset for any location and
any date with `C-u C-u M-x sunrise-sunset'.  This asks you for a
longitude, latitude, number of minutes difference from Coordinated
Universal Time, and date, and then tells you the times of sunrise and
sunset for that location on that date.

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

     (setq calendar-latitude 40.1)
     (setq calendar-longitude -88.2)
     (setq calendar-location-name "Urbana, IL")

Use one decimal place in the values of `calendar-latitude' and
`calendar-longitude'.

   Your time zone also affects the local time of sunrise and sunset.
Emacs usually gets time zone information from the operating system, but
if these values are not what you want (or if the operating system does
not supply them), you must set them yourself.  Here is an example:

     (setq calendar-time-zone -360)
     (setq calendar-standard-time-zone-name "CST")
     (setq calendar-daylight-time-zone-name "CDT")

The value of `calendar-time-zone' is the number of minutes difference
between your local standard time and Coordinated Universal Time
(Greenwich time).  The values of `calendar-standard-time-zone-name' and
`calendar-daylight-time-zone-name' are the abbreviations used in your
time zone.  Emacs displays the times of sunrise and sunset _corrected
for daylight savings time_.  *Note Daylight Savings::, for how daylight
savings time is determined.

   As a user, you might find it convenient to set the calendar location
variables for your usual physical location in your init file.  And when
you install Emacs on a machine, you can create a `default.el' file
which sets them properly for the typical location of most users of that
machine.  *Note Init File::.

\1f
File: xemacs.info,  Node: Lunar Phases,  Next: Other Calendars,  Prev: Sunrise/Sunset,  Up: Calendar/Diary

Phases of the Moon
------------------

   These calendar commands display the dates and times of the phases of
the moon (new moon, first quarter, full moon, last quarter).  This
feature is useful for debugging problems that "depend on the phase of
the moon."

`M'
     Display the dates and times for all the quarters of the moon for
     the three-month period shown (`calendar-phases-of-moon').

`M-x phases-of-moon'
     Display dates and times of the quarters of the moon for three
     months around today's date.

   Within the calendar, use the `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.

   Outside the calendar, use the command `M-x phases-of-moon' to
display the list of the phases of the moon for the current month and the
preceding and succeeding months.  For information about a different
month, use `C-u M-x phases-of-moon', which prompts for the month and
year.

   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 `calendar-time-zone' is void, Coordinated Universal Time
(the Greenwich time zone) is used.  *Note Daylight Savings::.

\1f
File: xemacs.info,  Node: Other Calendars,  Next: Calendar Systems,  Prev: Lunar Phases,  Up: Calendar/Diary

Conversion To and From Other Calendars
--------------------------------------

   The Emacs calendar displayed is _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.  The Emacs calendar can display any
month since 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.

   While Emacs cannot display other calendars, it can convert dates to
and from several other calendars.

* Menu:

* Calendar Systems::      The calendars Emacs understands
                            (aside from Gregorian).
* To Other Calendar::     Converting the selected date to various calendars.
* From Other Calendar::   Moving to a date specified in another calendar.
* Mayan Calendar::        Moving to a date specified in a Mayan calendar.

   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 `p' is a mnemonic for "print" since
Emacs "prints' the equivalent date in the echo area.

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

Supported Calendar Systems
==========================

   The ISO commercial calendar is used largely in Europe.

   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.

   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 _Julian day number_ or the _Astronomical day number_.

   The Hebrew calendar is used by tradition in the Jewish religion.  The
Emacs calendar program uses the Hebrew calendar to determine the dates
of Jewish holidays.  Hebrew calendar dates begin and end at sunset.

   The Islamic calendar is used in many predominantly Islamic countries.
Emacs uses it to determine the dates of Islamic 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 observance can vary
slightly from the dates computed by Emacs.  Islamic calendar dates begin
and end at sunset.

   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.

   The Maya of Central America used three separate, overlapping calendar
systems, the _long count_, the _tzolkin_, and the _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.

   The Copts use a calendar based on the ancient Egyptian solar
calendar.  Their calendar consists of twelve 30-day months followed by
an extra five-day period.  Once every fourth year they add a leap day
to this extra period to make it six days.  The Ethiopic calendar is
identical in structure, but has different year numbers and month names.

   The Persians use a solar calendar based on a design of Omar Khayyam.
Their calendar consists of twelve months of which the first six have 31
days, the next five have 30 days, and the last has 29 in ordinary years
and 30 in leap years.  Leap years occur in a complicated pattern every
four or five years.

   The Chinese calendar is a complicated system of lunar months arranged
into solar years.  The years go in cycles of sixty, each year containing
either twelve months in an ordinary year or thirteen months in a leap
year; each month has either 29 or 30 days.  Years, ordinary months, and
days are named by combining one of ten "celestial stems" with one of
twelve "terrestrial branches" for a total of sixty names that are
repeated in a cycle of sixty.

\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 init file, this automatically displays
a window with the day's diary entries, when you enter Emacs.  *Note
Init File::.  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 init
file:

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

this displays both the calendar and diary windows whenever you start
Emacs.  *Note Init File::.

   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.