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1 The Calendar and the Diary

Emacs provides the functions of a desk calendar, with a diary of planned or past events. It also has facilities for managing your appointments, and keeping track of how much time you spend working on certain projects.

To enter the calendar, type M-x calendar; this displays a three-month calendar centered on the current month, with point on the current date. With a numeric argument, as in C-u M-x calendar, it prompts you for the month and year to be the center of the three-month calendar. The calendar uses its own buffer, whose major mode is Calendar mode.

mouse-3 in the calendar brings up a menu of operations on a particular date; mouse-2 brings up a menu of commonly used calendar features that are independent of any particular date. To exit the calendar, type q.


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1.1 Movement in the Calendar

Calendar mode provides commands to move through the calendar in logical units of time such as days, weeks, months, and years. If you move outside the three months originally displayed, the calendar display scrolls automatically through time to make the selected date visible. Moving to a date lets you view its holidays or diary entries, or convert it to other calendars; moving by long time periods is also useful simply to scroll the calendar.


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1.1.1 Motion by Standard Lengths of Time

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

C-f

Move point one day forward (calendar-forward-day).

C-b

Move point one day backward (calendar-backward-day).

C-n

Move point one week forward (calendar-forward-week).

C-p

Move point one week backward (calendar-backward-week).

M-}

Move point one month forward (calendar-forward-month).

M-{

Move point one month backward (calendar-backward-month).

C-x ]

Move point one year forward (calendar-forward-year).

C-x [

Move point one year backward (calendar-backward-year).

The day and week commands are natural analogues of the usual Emacs commands for moving by characters and by lines. Just as C-n usually moves to the same column in the following line, in Calendar mode it moves to the same day in the following week. And C-p moves to the same day in the previous week.

The arrow keys are equivalent to C-f, C-b, C-n and C-p, just as they normally are in other modes.

The commands for motion by months and years work like those for weeks, but move a larger distance. The month commands M-} and M-{ move forward or backward by an entire month. The year commands C-x ] and C-x [ move forward or backward a whole year.

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

All these commands accept a numeric argument as a repeat count. For convenience, the digit keys and the minus sign specify numeric arguments in Calendar mode even without the Meta modifier. For example, 100 C-f moves point 100 days forward from its present location.


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1.1.2 Beginning or End of Week, Month or Year

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

C-a

Move point to start of week (calendar-beginning-of-week).

C-e

Move point to end of week (calendar-end-of-week).

M-a

Move point to start of month (calendar-beginning-of-month).

M-e

Move point to end of month (calendar-end-of-month).

M-<

Move point to start of year (calendar-beginning-of-year).

M->

Move point to end of year (calendar-end-of-year).

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

By default, weeks begin on Sunday. To make them begin on Monday instead, set the variable calendar-week-start-day to 1. To change which day headers are highlighted as weekend days, set the variable calendar-weekend-days.


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1.1.3 Specified 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).

g D

Move point to specified day of year (calendar-goto-day-of-year).

g w

Move point to specified week of year (calendar-iso-goto-week).

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 ‘2010’, not ‘10’.

g D (calendar-goto-day-of-year) prompts for a year and day number, and moves to that date. Negative day numbers count backward from the end of the year. g w (calendar-iso-goto-week) prompts for a year and week number, and moves to that week.

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).


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1.2 Scrolling in the Calendar

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 the calendar means moving the strip horizontally, so that new months become visible in the window.

>

Scroll calendar one month forward (calendar-scroll-left).

<

Scroll calendar one month backward (calendar-scroll-right).

C-v
<next>

Scroll forward by three months (calendar-scroll-left-three-months).

M-v
<prior>

Scroll backward by three months (calendar-scroll-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. > scrolls the calendar contents one month forward in time. < scrolls the contents one month 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.


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1.3 Counting Days

M-=

Display the number of days in the current region (calendar-count-days-region).

To determine the number of days in a range, set the mark on one date using C-<SPC>, move point to another date, and type M-= (calendar-count-days-region). The numbers of days shown is inclusive; that is, it includes the days specified by mark and point.


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1.4 Miscellaneous Calendar Commands

p d

Display day-in-year (calendar-print-day-of-year).

C-c C-l

Regenerate the calendar window (calendar-redraw).

<SPC>

Scroll the next window up (scroll-other-window).

<DEL>
S-<SPC>

Scroll the next window down (scroll-other-window-down).

q

Exit from calendar (calendar-exit).

To display the number of days 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. The count of days elapsed includes the selected date. The count of days remaining does not include that date.

If the calendar window text gets corrupted, type C-c C-l (calendar-redraw) 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) and <DEL> (scroll-other-window-down) to scroll the other window (if there is one) up or down, respectively. This is handy when you display a list of holidays or diary entries in another window.

To exit from the calendar, type q (calendar-exit). This buries all buffers related to the calendar, selecting other buffers. (If a frame contains a dedicated calendar window, exiting from the calendar deletes or iconifies that frame depending on the value of calendar-remove-frame-by-deleting.)


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1.5 Writing Calendar Files

You can write calendars and diary entries to HTML and LaTeX files.

The Calendar HTML commands produce files of HTML code that contain calendar, holiday, and diary entries. Each file applies to one month, and has a name of the format ‘yyyy-mm.html’, where yyyy and mm are the four-digit year and two-digit month, respectively. The variable cal-html-directory specifies the default output directory for the HTML files. To prevent holidays from being shown, customize cal-html-holidays.

Diary entries enclosed by < and > are interpreted as HTML tags (for example: this is a diary entry with <font color=”red”>some red text</font>). You can change the overall appearance of the displayed HTML pages (for example, the color of various page elements, header styles) via a stylesheet ‘cal.css’ in the directory containing the HTML files (see the value of the variable cal-html-css-default for relevant style settings).

H m

Generate a one-month calendar (cal-html-cursor-month).

H y

Generate a calendar file for each month of a year, as well as an index page (cal-html-cursor-year). By default, this command writes files to a yyyy subdirectory—if this is altered some hyperlinks between years will not work.

If the variable cal-html-print-day-number-flag is non-nil, then the monthly calendars show the day-of-the-year number. The variable cal-html-year-index-cols specifies the number of columns in the yearly index page.

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, with hours (cal-tex-cursor-week).

t w 2

Generate a two-page calendar for one week, with hours (cal-tex-cursor-week2).

t w 3

Generate an ISO-style calendar for one week, without hours (cal-tex-cursor-week-iso).

t w 4

Generate a calendar for one Monday-starting week, with hours (cal-tex-cursor-week-monday).

t w W

Generate a two-page calendar for one week, without hours (cal-tex-cursor-week2-summary).

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 monthly, filofax, and iso-week calendars only). If the variable cal-tex-rules is non-nil (the default is nil), the calendar displays ruled pages in styles that have sufficient room. Consult the documentation of the individual cal-tex functions to see which calendars support which features.

You can use the variable cal-tex-preamble-extra to insert extra LaTeX commands in the preamble of the generated document if you need to.


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1.6 Holidays

The Emacs calendar knows about many major and minor holidays, and can display them. You can add your own holidays to the default list.

mouse-3 Holidays
h

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

x

Mark holidays in the calendar window (calendar-mark-holidays).

u

Unmark calendar window (calendar-unmark).

a

List all holidays for the displayed three months in another window (calendar-list-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 mouse-3 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. See section calendar-holiday-marker. 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 (see section The Diary). If the variable calendar-mark-holidays-flag is non-nil, creating or updating the calendar marks holidays automatically.

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> and <DEL> in the calendar window to scroll that list up and down, respectively.

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 the variable calendar-view-holidays-initially-flag is non-nil, creating the calendar displays holidays in this way. 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 Bahá’í, Chinese, Christian, Islamic, and Jewish holidays; also the solstices and equinoxes.

The command M-x holiday-list 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. For example Veteran’s Day began in 1919, but is shown in earlier years.


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1.7 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.

mouse-3 Sunrise/sunset
S

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

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.

M-x calendar-sunrise-sunset-month

Display times of sunrise and sunset for the selected month.

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 mouse-3 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 saving time. See section Daylight Saving Time, for how daylight saving time is determined.

As a user, you might find it convenient to set the calendar location variables for your usual physical location in your ‘.emacs’ file. If you are a system administrator, you may want to set these variables for all users in a ‘default.el’ file. @xref{Init File}.


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1.8 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-lunar-phases).

M-x lunar-phases

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 lunar-phases 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 lunar-phases, 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 saving, when appropriate). See the discussion in the previous section. See section Times of Sunrise and Sunset.


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1.9 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 always 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.


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1.9.1 Supported Calendar Systems

The ISO commercial calendar is often used in business.

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 calendar implemented here is the arithmetical Persian calendar championed by Birashk, based on a 2,820-year cycle. It differs from the astronomical Persian calendar, which is based on astronomical events. As of this writing the first future discrepancy is projected to occur on March 20, 2025. It is currently not clear what the official calendar of Iran will be at that time.

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.

The Bahá’í calendar system is based on a solar cycle of 19 months with 19 days each. The four remaining intercalary days are placed between the 18th and 19th months.


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1.9.2 Converting To Other Calendars

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

mouse-3 Other calendars
p o

Display the selected date in various other calendars. (calendar-print-other-dates).

p c

Display ISO commercial calendar equivalent for selected day (calendar-iso-print-date).

p j

Display Julian date for selected day (calendar-julian-print-date).

p a

Display astronomical (Julian) day number for selected day (calendar-astro-print-day-number).

p h

Display Hebrew date for selected day (calendar-hebrew-print-date).

p i

Display Islamic date for selected day (calendar-islamic-print-date).

p f

Display French Revolutionary date for selected day (calendar-french-print-date).

p b

Display Bahá’í date for selected day (calendar-bahai-print-date).

p C

Display Chinese date for selected day (calendar-chinese-print-date).

p k

Display Coptic date for selected day (calendar-coptic-print-date).

p e

Display Ethiopic date for selected day (calendar-ethiopic-print-date).

p p

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

p m

Display Mayan date for selected day (calendar-mayan-print-date).

Otherwise, move point to the date you want to convert, then type the appropriate command starting with p from the table above. The prefix p is a mnemonic for “print”, since Emacs “prints” the equivalent date in the echo area. p o displays the date in all forms known to Emacs. You can also use mouse-3 and 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.)


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1.9.3 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-iso-goto-date).

g w

Move to a week specified in the ISO commercial calendar (calendar-iso-goto-week).

g j

Move to a date specified in the Julian calendar (calendar-julian-goto-date).

g a

Move to a date specified with an astronomical (Julian) day number (calendar-astro-goto-day-number).

g b

Move to a date specified in the Bahá’í calendar (calendar-bahai-goto-date).

g h

Move to a date specified in the Hebrew calendar (calendar-hebrew-goto-date).

g i

Move to a date specified in the Islamic calendar (calendar-islamic-goto-date).

g f

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

g C

Move to a date specified in the Chinese calendar (calendar-chinese-goto-date).

g p

Move to a date specified in the Persian calendar (calendar-persian-goto-date).

g k

Move to a date specified in the Coptic calendar (calendar-coptic-goto-date).

g e

Move to a date specified in the Ethiopic calendar (calendar-ethiopic-goto-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 (@pxref{Completion Exit}) 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 issue 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 calendar-hebrew-list-yahrzeits 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.


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1.10 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.

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.


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1.10.1 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. The default is ‘~/.emacs.d/diary’, though for compatibility with older versions Emacs will use ‘~/diary’ if it exists.

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. Here’s an example:

12/22/2015  Twentieth wedding anniversary!
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, 2016 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.

You can also use a format where the first line of a diary entry consists only of the date or day name (with no following blanks or punctuation). For example:

02/11/2012
      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

This entry will have a different appearance if you use the simple diary display (see section Diary Display). The simple diary display omits the date line at the beginning; only the continuation lines appear. 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.


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1.10.2 Displaying the Diary

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. In the following, key bindings refer to the Calendar buffer.

mouse-3 Diary
d

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

s

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

m

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

u

Unmark the calendar window (calendar-unmark).

M-x diary-print-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 buffer the diary entries for the selected date in the calendar. The mode line of the new buffer shows the date of the diary entries. Holidays are shown either in the buffer or in the mode line, depending on the display method you choose (see section Diary Display). 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 mouse-3 on the date, and then choose Diary entries from the menu that appears. If the variable calendar-view-diary-initially-flag is non-nil, creating the calendar lists the diary entries for the current date (provided the current date is visible).

To get a broader view of which days are mentioned in the diary, use the m command. This marks the dates that have diary entries in a different face. See section diary-entry-marker.

This command applies both to the months that are currently visible and to those that subsequently become visible after scrolling. To turn marking off and erase the current marks, type u, which also turns off holiday marks (see section Holidays). If the variable calendar-mark-diary-entries-flag is non-nil, creating or updating the calendar marks diary dates automatically.

To prevent an individual diary entry from being marked in the calendar, insert the string that diary-nonmarking-symbol specifies (the default is ‘&’) at the beginning of the entry, before the date. This has no effect on display of the entry in the diary buffer; it only affects marks on dates in the calendar. Nonmarking entries can be useful for generic entries that would otherwise mark many different dates.

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

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 diary-number-of-entries specifies how many days to include. See section diary-number-of-entries.

If you put (diary) in your ‘.emacs’ file, this automatically displays a window with the day’s diary entries when you start Emacs.

Some people like to receive email notifications of events in their diary. 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.


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1.10.3 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) and ISO order (year, month, day) as options.

4/20/12  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, 2012. 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 ‘11/12/2012’ or ‘11/12/12’.

Dates can also have the form ‘monthname day’ or ‘monthname day, year’, where the month’s name can be spelled in full or abbreviated (with or without a period). The preferred abbreviations for month and day names can be set using the variables calendar-abbrev-length, calendar-month-abbrev-array, and calendar-day-abbrev-array. The default is to use the first three letters of a name as its abbreviation. 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 ‘*’; 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), or the ISO style (in which the order is year, month, day), type M-x calendar-set-date-style while in the calendar, or customize the variable calendar-date-style. This affects how diary dates are interpreted, date display, and the order in which some commands expect their arguments to be given.

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 as described above, or spell it in full; case is not significant.


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1.10.4 Commands to Add to the Diary

While in the calendar, there are several commands to create diary entries. The basic commands are listed here; more sophisticated commands are in the next section (see section Special Diary Entries). Entries can also be based on non-Gregorian calendars. See section Diary Entries Using non-Gregorian Calendars.

i d

Add a diary entry for the selected date (diary-insert-entry).

i w

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

i m

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

i y

Add a diary entry for the selected day of the year (diary-insert-yearly-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 the 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 prefix 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. Saving the diary file after using any of the above insertion commands will automatically update the diary marks in the calendar window, if appropriate. You can use the command calendar-redraw to force an update at any time.


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1.10.5 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 (diary-insert-anniversary-entry).

i b

Add a block diary entry for the current region (diary-insert-block-entry).

i c

Add a cyclic diary entry starting at the date (diary-insert-cyclic-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:

%%(diary-anniversary 10 31 1988) Arthur's birthday

This entry applies to October 31 in any year after 1988; ‘10 31 1988’ specifies the date. (If you are using the European or ISO calendar style, the input order of month, day and year is different.) 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, 2012 through July 10, 2012:

%%(diary-block 6 24 2012 7 10 2012) Vacation

The ‘6 24 2012’ indicates the starting date and the ‘7 10 2012’ indicates the stopping date. (Again, if you are using the European or ISO calendar style, the input order of month, day and year is different.)

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 2012) Renew medication

This entry applies to March 1, 2012 and every 50th day following; ‘3 1 2012’ specifies the starting date. (If you are using the European or ISO calendar style, the input order of month, day and year is different.)

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

Marking sexp diary entries in the calendar can be 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 fourth Thursday in November:

&%%(diary-float 11 4 4) 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 second 4 specifies the fourth Thursday (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.

Each of the standard sexp diary entries takes an optional parameter specifying the name of a face or a single-character string to use when marking the entry in the calendar. Most generally, sexp diary entries can perform arbitrary computations to determine when they apply. See section Sexp Entries and the Fancy Diary Display.


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1.11 Appointments

If you have a diary entry for an appointment, and that diary entry begins with a recognizable time of day, Emacs can warn you in advance that an appointment is pending. Emacs alerts you to the appointment by displaying a message in your chosen format, as specified by the variable appt-display-format. If the value of appt-audible is non-nil, the warning includes an audible reminder. In addition, if appt-display-mode-line is non-nil, Emacs displays the number of minutes to the appointment on the mode line.

If appt-display-format has the value window, then the variable appt-display-duration controls how long the reminder window is visible for; and the variables appt-disp-window-function and appt-delete-window-function give the names of functions used to create and destroy the window, respectively.

To enable appointment notification, type M-x appt-activate. With a positive argument, it enables notification; with a negative argument, it disables notification; with no argument, it toggles. Enabling notification also sets up an appointment list for today from the diary file, giving all diary entries found with recognizable times of day, and reminds you just before each of them.

For example, suppose the diary file contains these lines:

Monday
  9:30am Coffee break
 12:00pm Lunch

Then on Mondays, you will be reminded at around 9:20am about your coffee break and at around 11:50am about lunch. The variable appt-message-warning-time specifies how many minutes (default 12) in advance to warn you. This is a default warning time. Each appointment can specify a different warning time by adding a piece matching appt-warning-time-regexp (see that variable’s documentation for details).

You can write times in am/pm style (with ‘12:00am’ standing for midnight and ‘12:00pm’ standing for noon), or 24-hour European/military style. You need not be consistent; your diary file can have a mixture of the two styles. Times must be at the beginning of diary entries if they are to be recognized.

Emacs updates the appointments list from the diary file automatically just after midnight. You can force an update at any time by re-enabling appointment notification. Both these actions also display the day’s diary buffer, unless you set appt-display-diary to nil. The appointments list is also updated whenever the diary file (or a file it includes; see Fancy Diary Display) is saved.

You can also use the appointment notification facility like an alarm clock. The command M-x appt-add adds entries to the appointment list without affecting your diary file. You delete entries from the appointment list with M-x appt-delete.


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1.12 Importing and Exporting Diary Entries

You can transfer diary entries between Emacs diary files and a variety of other formats.

You can import diary entries from Outlook-generated appointment messages. While viewing such a message in Rmail or Gnus, do M-x diary-from-outlook to import the entry. You can make this command recognize additional appointment message formats by customizing the variable diary-outlook-formats. Other mail clients can set diary-from-outlook-function to an appropriate value.

The icalendar package allows you to transfer data between your Emacs diary file and iCalendar files, which are defined in RFC 2445—Internet Calendaring and Scheduling Core Object Specification (iCalendar) (as well as the earlier vCalendar format).

The command icalendar-import-buffer extracts iCalendar data from the current buffer and adds it to your diary file. This function is also suitable for automatic extraction of iCalendar data; for example with the Rmail mail client one could use:

(add-hook 'rmail-show-message-hook 'icalendar-import-buffer)

The command icalendar-import-file imports an iCalendar file and adds the results to an Emacs diary file. For example:

(icalendar-import-file "/here/is/calendar.ics"
                       "/there/goes/ical-diary")

You can use an #include directive to add the import file contents to the main diary file, if these are different files. See section Fancy Diary Display.

Use icalendar-export-file to interactively export an entire Emacs diary file to iCalendar format. To export only a part of a diary file, mark the relevant area, and call icalendar-export-region. In both cases, Emacs appends the result to the target file.


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1.13 Daylight Saving Time

Emacs understands the difference between standard time and daylight saving time—the times given for sunrise, sunset, solstices, equinoxes, and the phases of the moon take that into account. The rules for daylight saving 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: calendar-daylight-savings-starts and calendar-daylight-savings-ends.

These values should be Lisp expressions that refer to the variable year, and evaluate to the Gregorian date on which daylight saving 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 saving time.

Emacs uses these expressions to determine the starting date of daylight saving 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 2 0 3 year)
(calendar-nth-named-day 1 0 11 year)

That is, the second 0th day (Sunday) of the third month (March) in the year specified by year, and the first Sunday of the eleventh month (November) of that year. If daylight saving time were changed to start on October 1, you would set calendar-daylight-savings-starts to this:

(list 10 1 year)

If there is no daylight saving 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 saving time and standard time, measured in minutes. The value for Cambridge, Massachusetts is 60.

Finally, 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 saving time should occur. For Cambridge, Massachusetts both variables’ values are 120.


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1.14 Summing Time Intervals

The timeclock package adds up time intervals, so you can (for instance) keep track of how much time you spend working on particular projects.

Use the M-x timeclock-in command when you start working on a project, and M-x timeclock-out command when you’re done. Each time you do this, it adds one time interval to the record of the project. You can change to working on a different project with M-x timeclock-change.

Once you’ve collected data from a number of time intervals, you can use M-x timeclock-workday-remaining to see how much time is left to work today (assuming a typical average of 8 hours a day), and M-x timeclock-when-to-leave which will calculate when you’re done.

If you want Emacs to display the amount of time left of your workday in the mode line, either customize the timeclock-modeline-display variable and set its value to t, or invoke the M-x timeclock-modeline-display command.

Terminating the current Emacs session might or might not mean that you have stopped working on the project and, by default, Emacs asks you. You can, however, customize the value of the variable timeclock-ask-before-exiting to nil to avoid the question; then, only an explicit M-x timeclock-out or M-x timeclock-change will tell Emacs that the current interval is over.

The timeclock functions work by accumulating the data in a file called ‘~/.emacs.d/timelog’. You can specify a different name for this file by customizing the variable timeclock-file. If you edit the timeclock file manually, or if you change the value of any of timeclock’s customizable variables, you should run the command M-x timeclock-reread-log to update the data in Emacs from the file.


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1.15 More advanced features of the Calendar and Diary

This section describes some of the more advanced/specialized features of the calendar and diary. It starts with some of the many ways in which you can customize the calendar and diary to suit your personal tastes.


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1.15.1 Customizing the Calendar

The calendar display unfortunately cannot be changed from three months, but you can customize the whitespace used by setting the variables: calendar-left-margin, calendar-day-header-width, calendar-day-digit-width, calendar-column-width, and calendar-intermonth-spacing. To display text between the months, for example week numbers, customize the variables calendar-intermonth-header and calendar-intermonth-text as described in their documentation.

The variable calendar-month-header controls the text that appears above each month in the calendar. By default, it shows the month and year. The variable calendar-day-header-array controls the text that appears above each day’s column in every month. By default, it shows the first two letters of each day’s name.

The variable calendar-holiday-marker specifies how to mark a date that is a holiday. Its value may be a single-character string 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 function calendar-mark-today uses calendar-today-marker to mark today’s date. By default, the calendar uses faces named holiday, diary, and calendar-today for these purposes.

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 calendar-initial-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 calendar-today-visible-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 mark today’s date; to do that use either of the functions calendar-mark-today or calendar-star-date:

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

A similar normal hook, calendar-today-invisible-hook is run if the current date is not visible in the window.

Each of the calendar cursor motion commands runs the hook calendar-move-hook after it moves the cursor.


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1.15.2 Customizing the Holidays

There are several variables listing the default holidays that Emacs knows about. These are: holiday-general-holidays, holiday-local-holidays, holiday-solar-holidays, holiday-bahai-holidays, holiday-christian-holidays, holiday-hebrew-holidays, holiday-islamic-holidays, holiday-oriental-holidays, and holiday-other-holidays. The names should be self-explanatory; e.g., holiday-solar-holidays lists sun- and moon-related holidays.

You can customize these lists of holidays to your own needs, deleting or adding holidays as described below. Set any of them to nil to not show the associated holidays.

The general holidays are, by default, holidays common throughout the United States. In contrast, holiday-local-holidays and holiday-other-holidays are both empty by default. These are intended for system-wide settings and your individual use, respectively.

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 calendar-bahai-all-holidays-flag, calendar-christian-all-holidays-flag, calendar-hebrew-all-holidays-flag, or calendar-islamic-all-holidays-flag to t.

Each of the holiday variables is a list of holiday forms, each 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 argument string is always the description of the holiday, as a string.

(holiday-fixed month day string)

A fixed date on the Gregorian calendar.

(holiday-float month dayname k string

&optional day) The kth dayname (dayname=0 for Sunday, and so on) after or before Gregorian date month, day. Negative k means count back from the end of the month. Optional day defaults to 1 if k is positive, and the last day of month otherwise.

(holiday-chinese month day string)

A fixed date on the Chinese calendar.

(holiday-hebrew month day string)

A fixed date on the Hebrew calendar.

(holiday-islamic month day string)

A fixed date on the Islamic calendar.

(holiday-julian month day string)

A fixed date on the Julian calendar.

(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 in the form of a list (month day year), or nil if the holiday doesn’t happen this year.

(if condition 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 (i.e., the fourteenth day of the seventh month). You can do this as follows:

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

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 July:

(holiday-float 7 1 4 "Hurricane Supplication Day")

Here the 7 specifies July, 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 Bahá’í, Chinese, Hebrew, Islamic, and Julian calendars too. For example,

(setq holiday-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 (zerop (% 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 (zerop (% displayed-year 4))
    (holiday-fixed 11
           (calendar-extract-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 holiday-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 4 2012) "Lunar Eclipse") ((11 13 2012) "Solar Eclipse") ... )

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1.15.3 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-mayan-goto-long-count-date).

g m n t

Move to the next occurrence of a place in the tzolkin calendar (calendar-mayan-next-tzolkin-date).

g m p t

Move to the previous occurrence of a place in the tzolkin calendar (calendar-mayan-previous-tzolkin-date).

g m n h

Move to the next occurrence of a place in the haab calendar (calendar-mayan-next-haab-date).

g m p h

Move to the previous occurrence of a place in the haab calendar (calendar-mayan-previous-haab-date).

g m n c

Move to the next occurrence of a place in the calendar round (calendar-mayan-next-calendar-round-date).

g m p c

Move to the previous occurrence of a place in the calendar round (calendar-mayan-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 7.17.18.13.3, 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 by 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 (@pxref{Completion Exit}) whenever it asks you to type a Mayan name, so you don’t have to worry about spelling.


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1.15.4 Date Display Format

You can customize the way dates are displayed in the diary, mode lines, and 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 default ISO date representation is:

((format "%s-%.2d-%.2d" year (string-to-number month)
         (string-to-number day)))

Another typical American format is:

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

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1.15.5 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 is:

(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 ")"))

Note that few calendar functions return a time of day (at present, only solar functions).


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1.15.6 Customizing the Diary

Ordinarily, the diary window indicates any holidays that fall on the date of the diary entries, either in the mode line or the buffer itself. The process of checking for holidays can be slow, depending on the defined holidays. In that case, setting diary-show-holidays-flag to nil will speed up the diary display.

The variable diary-number-of-entries controls the number of days of diary entries to be displayed at one time. It affects the initial display when calendar-view-diary-initially-flag is t, as well as the command M-x diary. For example, a value of 1 (the default) displays only the current day’s diary entries, whereas a value of 2 will also show the next day’s entries. The value can also be a vector of seven integers: 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.

You can customize the form of dates in your diary file 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 (see Regular Expressions in the Emacs Lisp Reference Manual) 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 capitalization and abbreviation (as specified by calendar-month-abbrev-array and calendar-day-abbrev-array). 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 provided by diary-american-date-forms:

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

The variables diary-european-date-forms and diary-iso-date-forms provide other default styles.

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. For example, the default value of diary-european-date-forms is:

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


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1.15.7 Diary Entries Using non-Gregorian Calendars

As well as entries based on the standard Gregorian calendar, your diary can have entries based on Bahá’í, Chinese, Hebrew, or Islamic dates. Recognition of such entries can be time-consuming, however, and since 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 'diary-nongregorian-listing-hook 'diary-hebrew-list-entries)
(add-hook 'diary-nongregorian-marking-hook 'diary-hebrew-mark-entries)

Similarly, for Islamic, Bahá’í and Chinese entries, add diary-islamic-list-entries and diary-islamic-mark-entries, diary-bahai-list-entries and diary-bahai-mark-entries, or diary-chinese-list-entries and diary-chinese-mark-entries.

These diary entries have the same formats as Gregorian-date diary entries; except that diary-bahai-entry-symbol (default ‘B’) must precede a Bahá’í date, diary-chinese-entry-symbol (default ‘C’) a Chinese date, diary-hebrew-entry-symbol (default ‘H’) a Hebrew date, and diary-islamic-entry-symbol (default ‘I’) an Islamic date. Moreover, non-Gregorian month names may not be abbreviated (because the first three letters are often not unique). (Note also that you must use “Adar I” if you want Adar of a common Hebrew year.) 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 an Islamic-date diary entry that matches Dhu al-Qada 25:

IDhu al-Qada 25 Happy Islamic birthday!

As with Gregorian-date diary entries, non-Gregorian entries are nonmarking if preceded by diary-nonmarking-symbol (default ‘&’).

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 Bahá’í, Chinese, Hebrew, or Islamic calendars:

i h d

diary-hebrew-insert-entry

i h m

diary-hebrew-insert-monthly-entry

i h y

diary-hebrew-insert-yearly-entry

i i d

diary-islamic-insert-entry

i i m

diary-islamic-insert-monthly-entry

i i y

diary-islamic-insert-yearly-entry

i B d

diary-bahai-insert-entry

i B m

diary-bahai-insert-monthly-entry

i B y

diary-bahai-insert-yearly-entry

i C d

diary-chinese-insert-entry

i C m

diary-chinese-insert-monthly-entry

i C y

diary-chinese-insert-yearly-entry

i C a

diary-chinese-insert-anniversary-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. The basic commands add an entry for the specific non-Gregorian date, the ‘monthly’ commands for the given non-Gregorian day-within-month in every month, and the ‘yearly’ commands for the given non-Gregorian day and month in every year.


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1.15.8 Diary Display

Diary display works by preparing the list of diary entries and then running the function specified by the variable diary-display-function. The default value diary-fancy-display displays diary entries and holidays by copying them into a special buffer that exists only for the sake of display. Copying diary entries to a separate buffer provides an opportunity to change the displayed text to make it prettier—for example, to sort the entries by the dates they apply to.

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

The fancy diary buffer enables View mode (@pxref{View Mode}).

The alternative display method diary-simple-display shows the actual diary buffer, and uses invisible text to hide entries that don’t apply. Holidays are shown in the mode line. The advantage of this method is that you can edit the buffer and save your changes directly to the diary file. This method is not as flexible as the fancy method, however. For example, it cannot sort entries. Another disadvantage is that invisible text can be confusing. For example, if you copy a region of text in order to paste it elsewhere, invisible text may be included. Similarly, since the diary buffer as you see it is an illusion, simply printing the buffer may not print what you see on your screen.

For this reason, there is a special command to print hard copy of the diary buffer as it appears; this command is M-x diary-print-entries. It works with either display method, although with the fancy display you can also print the buffer like any other. To print a hard copy of a day-by-day diary for a week, position point on the first day of the week, type 7 d, and then do M-x diary-print-entries. As usual, the inclusion of the holidays slows down the display slightly; you can speed things up by setting the variable diary-show-holidays-flag to nil.

This command prepares a temporary buffer that contains only the diary entries currently visible in the diary buffer. Unlike with the simple display, the other irrelevant entries are really absent, not just hidden. After preparing the buffer, it runs the hook diary-print-entries-hook. The default value of this hook sends the data directly to the printer with the command lpr-buffer (@pxref{Printing}). 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 edit the diary entries as they appear in the simple diary 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 in the simple display! 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 simple diary buffer, it is best to display the entire file with s (diary-show-all-entries).


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1.15.9 Fancy Diary Display

The following features only work with the fancy diary display.

You can use the normal hook diary-list-entries-hook to sort each day’s diary entries by their time of day. Here’s how:

(add-hook 'diary-list-entries-hook 'diary-sort-entries t)

For each day, this sorts diary entries that begin with a recognizable time of day according to their times. Diary entries without times come first within each day. Note how the sort command is placed at the end of the hook list, in case earlier members of the list change the order of the diary entries, or add items.

You can write ‘comments’ in diary entries, by setting the variables diary-comment-start and diary-comment-end to strings that delimit comments. The fancy display does not print comments. You might want to put meta-data for the use of other packages (e.g., the appointment package, see section Appointments) inside comments.

Your main diary file can include other files. This permits a group of people to share a diary file for events that apply to all of them. Lines in the diary file starting with diary-include-string:

#include "filename"

include the diary entries from the file filename in the fancy diary buffer. The include mechanism is recursive, so that included files can include other files, and so on (you must be careful not to have a cycle of inclusions, of course). Here is how to enable the include facility:

(add-hook 'diary-list-entries-hook 'diary-include-other-diary-files)
(add-hook 'diary-mark-entries-hook 'diary-mark-included-diary-files)

The include mechanism works only with the fancy diary display, because simple diary display shows the entries directly from your diary file.


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1.15.10 Sexp Entries and the Fancy Diary Display

Sexp diary entries allow you to do more than just have complicated conditions under which a diary entry applies. Sexp entries should be preceded by diary-sexp-entry-symbol (default ‘%%’) in the diary file. With the fancy diary display, sexp entries can generate the text of the entry depending on the date itself.

For example, an anniversary diary entry can insert the number of years since the anniversary date into the text of the diary entry. Thus the ‘%d’ in this diary entry:

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

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

Arthur's birthday (42 years old)

If the diary file instead contains this entry:

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

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

Arthur's 42nd birthday

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

%%(diary-cyclic 50 1 1 2012) Renew medication (%d%s time)

looks like this:

Renew medication (5th time)

in the fancy diary display on September 7, 2012.

There is an early-reminder diary sexp that includes its entry in the diary not only on the date of occurrence, but also on earlier dates. For example, if you want a reminder a week before your anniversary, you can use

%%(diary-remind '(diary-anniversary 12 22 1968) 7) Ed's anniversary

and the fancy diary will show ‘Ed's anniversary’ both on December 15 and on December 22.

The function diary-date applies to dates described by a month, day, year combination, each of which can be an integer, a list of integers, or t (meaning all values). For example,

%%(diary-date '(10 11 12) 22 t) Rake leaves

causes the fancy diary to show

Rake leaves

on October 22, November 22, and December 22 of every year.

The function diary-float allows you to describe diary entries that apply to dates like the third Friday of November, or the last Tuesday in April. The parameters are the month, dayname, and an index n. The entry appears on the nth dayname after the first day of month, where dayname=0 means Sunday, 1 means Monday, and so on. If n is negative it counts backward from the end of month. The value of month can be a list of months, a single month, or t to specify all months. You can also use an optional parameter day to specify the nth dayname on or after/before day of month; the value of day defaults to 1 if n is positive and to the last day of month if n is negative. For example,

%%(diary-float t 1 -1) Pay rent

causes the fancy diary to show

Pay rent

on the last Monday of every month.

The generality of sexp diary entries lets you specify any diary entry that you can describe algorithmically. A sexp diary entry contains an expression that computes whether the entry applies to any given date. If its value is non-nil, the entry applies to that date; otherwise, it does not. The expression can use the variable date to find the date being considered; its value is a list (month day year) that refers to the Gregorian calendar.

The sexp diary entry applies to a date when the expression’s value is non-nil, but some values have more specific meanings. If the value is a string, that string is a description of the event which occurs on that date. The value can also have the form (mark . string); then mark specifies how to mark the date in the calendar, and string is the description of the event. If mark is a single-character string, that character appears next to the date in the calendar. If mark is a face name, the date is displayed in that face. If mark is nil, that specifies no particular highlighting for the date.

Suppose you get paid on the 21st of the month if it is a weekday, and on the Friday before if the 21st is on a weekend. Here is how to write a sexp diary entry that matches those dates:

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

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

%%(diary-sunrise-sunset)

Make a diary entry for today’s local times of sunrise and sunset.

%%(diary-lunar-phases)

Make a diary entry for the phases (quarters) of the moon.

%%(diary-day-of-year)

Make a diary entry with today’s day number in the current year and the number of days remaining in the current year.

%%(diary-iso-date)

Make a diary entry with today’s equivalent ISO commercial date.

%%(diary-julian-date)

Make a diary entry with today’s equivalent Julian calendar date.

%%(diary-astro-day-number)

Make a diary entry with today’s equivalent astronomical (Julian) day number.

%%(diary-bahai-date)

Make a diary entry with today’s equivalent Bahá’í calendar date.

%%(diary-chinese-date)

Make a diary entry with today’s equivalent Chinese calendar date.

%%(diary-coptic-date)

Make a diary entry with today’s equivalent Coptic calendar date.

%%(diary-ethiopic-date)

Make a diary entry with today’s equivalent Ethiopic calendar date.

%%(diary-french-date)

Make a diary entry with today’s equivalent date on the French Revolutionary calendar.

%%(diary-hebrew-date)

Make a diary entry with today’s equivalent Hebrew calendar date.

%%(diary-islamic-date)

Make a diary entry with today’s equivalent Islamic calendar date.

%%(diary-mayan-date)

Make a diary entry with today’s equivalent Mayan calendar date.

%%(diary-persian-date)

Make a diary entry with today’s equivalent Persian calendar date.

For example, including the diary entry

&%%(diary-hebrew-date)

causes every day’s diary display to contain the equivalent date on the Hebrew calendar, if you are using the fancy diary display. (With simple diary display, the literal line ‘&%%(diary-hebrew-date)’ appears in the diary for any date.)

This function has been used to construct certain standard Hebrew sexp diary entries:

%%(diary-hebrew-rosh-hodesh)

Make a diary entry that tells the occurrence and ritual announcement of each new Hebrew month.

%%(diary-hebrew-parasha)

Make a Saturday diary entry that tells the weekly synagogue scripture reading.

%%(diary-hebrew-sabbath-candles)

Make a Friday diary entry that tells the local time of Sabbath candle lighting.

%%(diary-hebrew-omer)

Make a diary entry that gives the omer count, when appropriate.

%%(diary-hebrew-yahrzeit month day year) name

Make a diary entry marking the anniversary of a date of death. The date is the Gregorian (civil) date of death. The diary entry appears on the proper Hebrew calendar anniversary and on the day before. (The order of the parameters changes according to the calendar date style; for example in the European style to day, month, year.)

%%(diary-hebrew-birthday month day year)

Make a diary entry for a birthday on the Hebrew calendar.

All the functions documented above take an optional argument mark which specifies how to mark the date in the calendar display. If one of these functions decides that it applies to a certain date, it returns a value that contains mark, as described above.


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