calendar.texi 67.6 KB
Newer Older
Glenn Morris's avatar
Glenn Morris committed
1 2
@c This is part of the Emacs manual.
@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001,
Glenn Morris's avatar
Glenn Morris committed
3
@c   2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
Glenn Morris's avatar
Glenn Morris committed
4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243
@c See file emacs.texi for copying conditions.
@node Calendar/Diary, Gnus, Dired, Top
@chapter The Calendar and the Diary
@cindex calendar
@findex calendar

  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 @kbd{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 @kbd{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.

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

@iftex
  This chapter describes the basic calendar features.
@inforef{Advanced Calendar/Diary Usage,, emacs-xtra}, for information
about more specialized features.
@end iftex

@menu
* Calendar Motion::     Moving through the calendar; selecting a date.
* Scroll Calendar::     Bringing earlier or later months onto the screen.
* Counting Days::       How many days are there between two dates?
* General Calendar::    Exiting or recomputing the calendar.
* Writing Calendar Files:: Writing calendars to files of various formats.
* Holidays::            Displaying dates of holidays.
* Sunrise/Sunset::      Displaying local times of sunrise and sunset.
* Lunar Phases::        Displaying phases of the moon.
* Other Calendars::     Converting dates to other calendar systems.
* Diary::               Displaying events from your diary.
* Appointments::	Reminders when it's time to do something.
* Importing Diary::     Converting diary events to/from other formats.
* Daylight Saving::     How to specify when daylight saving time is active.
* Time Intervals::      Keeping track of time intervals.
@ifnottex
* Advanced Calendar/Diary Usage:: Advanced Calendar/Diary customization.
@end ifnottex
@end menu

@node Calendar Motion
@section Movement in the Calendar

@cindex moving inside 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.

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

@node Calendar Unit Motion
@subsection 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.

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

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

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

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

  The easiest way to remember these commands is to consider months and
years analogous to paragraphs and pages of text, respectively.  But
the commands themselves are not quite analogous.  The ordinary Emacs
paragraph commands move to the beginning or end of a paragraph,
whereas these month and year commands move by an entire month or an
entire year, 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,
@kbd{100 C-f} moves point 100 days forward from its present location.

@node Move to Beginning or End
@subsection 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 beginning or end of a week, month or
year:

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

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

@vindex calendar-week-start-day
@cindex weeks, which day they start on
@cindex calendar, first day of week
  By default, weeks begin on Sunday.  To make them begin on Monday
instead, set the variable @code{calendar-week-start-day} to 1.

@node Specified Dates
@subsection Specified Dates

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

@table @kbd
@item g d
Move point to specified date (@code{calendar-goto-date}).
@item g D
Move point to specified day of year (@code{calendar-goto-day-of-year}).
@item g w
Move point to specified week of year (@code{calendar-goto-iso-week}).
@item o
Center calendar around specified month (@code{calendar-other-month}).
@item .
Move point to today's date (@code{calendar-goto-today}).
@end table

@kindex g d @r{(Calendar mode)}
@findex calendar-goto-date
  @kbd{g d} (@code{calendar-goto-date}) prompts for a year, a month, and a day
of the month, and then 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 @samp{1990}, not @samp{90}.

@kindex g D @r{(Calendar mode)}
@findex calendar-goto-day-of-year
@kindex g w @r{(Calendar mode)}
@findex calendar-goto-iso-week
  @kbd{g D} (@code{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.  @kbd{g w}
(@code{calendar-goto-iso-week}) prompts for a year and week number,
and moves to that week.

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

@kindex . @r{(Calendar mode)}
@findex calendar-goto-today
  You can return to today's date with @kbd{.}@:
(@code{calendar-goto-today}).

@node Scroll Calendar
@section Scrolling in the Calendar

@cindex 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.

@table @kbd
@item >
244
Scroll calendar one month forward (@code{calendar-scroll-left}).
Glenn Morris's avatar
Glenn Morris committed
245
@item <
246
Scroll calendar one month backward (@code{calendar-scroll-right}).
Glenn Morris's avatar
Glenn Morris committed
247 248 249
@item C-v
@itemx @key{NEXT}
Scroll calendar three months forward
250
(@code{calendar-scroll-left-three-months}).
Glenn Morris's avatar
Glenn Morris committed
251 252 253
@item M-v
@itemx @key{PRIOR}
Scroll calendar three months backward
254
(@code{calendar-scroll-right-three-months}).
Glenn Morris's avatar
Glenn Morris committed
255 256 257
@end table

@kindex > @r{(Calendar mode)}
258
@findex calendar-scroll-left
Glenn Morris's avatar
Glenn Morris committed
259
@kindex < @r{(Calendar mode)}
260
@findex calendar-scroll-right
Glenn Morris's avatar
Glenn Morris committed
261 262 263 264 265 266 267
  The most basic calendar scroll commands scroll by one month at a
time.  This means that there are two months of overlap between the
display before the command and the display after.  @kbd{>} scrolls the
calendar contents one month forward in time.  @kbd{<} scrolls the
contents one month backwards in time.

@kindex C-v @r{(Calendar mode)}
268
@findex calendar-scroll-left-three-months
Glenn Morris's avatar
Glenn Morris committed
269
@kindex M-v @r{(Calendar mode)}
270
@findex calendar-scroll-right-three-months
Glenn Morris's avatar
Glenn Morris committed
271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304
  The commands @kbd{C-v} and @kbd{M-v} scroll the calendar by an entire
``screenful''---three months---in analogy with the usual meaning of
these commands.  @kbd{C-v} makes later dates visible and @kbd{M-v} makes
earlier dates visible.  These commands take a numeric argument as a
repeat count; in particular, since @kbd{C-u} multiplies the next command
by four, typing @kbd{C-u C-v} scrolls the calendar forward by a year and
typing @kbd{C-u M-v} scrolls the calendar backward by a year.

  The function keys @key{NEXT} and @key{PRIOR} are equivalent to
@kbd{C-v} and @kbd{M-v}, just as they are in other modes.

@node Counting Days
@section Counting Days

@table @kbd
@item M-=
Display the number of days in the current region
(@code{calendar-count-days-region}).
@end table

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

@node General Calendar
@section Miscellaneous Calendar Commands

@table @kbd
@item p d
Display day-in-year (@code{calendar-print-day-of-year}).
@item C-c C-l
305
Regenerate the calendar window (@code{calendar-redraw}).
Glenn Morris's avatar
Glenn Morris committed
306 307 308 309 310
@item SPC
Scroll the next window up (@code{scroll-other-window}).
@item DEL
Scroll the next window down (@code{scroll-other-window-down}).
@item q
311
Exit from calendar (@code{calendar-exit}).
Glenn Morris's avatar
Glenn Morris committed
312 313 314 315 316 317 318 319 320 321 322 323 324
@end table

@kindex p d @r{(Calendar mode)}
@cindex day of year
@findex calendar-print-day-of-year
  To display the number of days elapsed since the start of the year, or
the number of days remaining in the year, type the @kbd{p d} command
(@code{calendar-print-day-of-year}).  This displays both of those
numbers in the echo area.  The count of days elapsed includes the
selected date.  The count of days remaining does not include that
date.

@kindex C-c C-l @r{(Calendar mode)}
325
@findex calendar-redraw
Glenn Morris's avatar
Glenn Morris committed
326
  If the calendar window text gets corrupted, type @kbd{C-c C-l}
327
(@code{calendar-redraw}) to redraw it.  (This can only happen if you use
Glenn Morris's avatar
Glenn Morris committed
328 329 330 331 332 333 334 335 336 337
non-Calendar-mode editing commands.)

@kindex SPC @r{(Calendar mode)}
  In Calendar mode, you can use @kbd{SPC} (@code{scroll-other-window})
and @kbd{DEL} (@code{scroll-other-window-down}) to scroll the other
window up or down, respectively.  This is handy when you display a list
of holidays or diary entries in another window.

@kindex q @r{(Calendar mode)}
@findex exit-calendar
338 339
@vindex calendar-remove-frame-by-deleting
  To exit from the calendar, type @kbd{q} (@code{calendar-exit}).  This
Glenn Morris's avatar
Glenn Morris committed
340 341
buries all buffers related to the calendar, selecting other buffers.
(If a frame contains a dedicated calendar window, exiting from the
342 343
calendar deletes or iconifies that frame depending on the value of
@code{calendar-remove-frame-by-deleting}.)
Glenn Morris's avatar
Glenn Morris committed
344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461

@node Writing Calendar Files
@section Writing Calendar Files

  These packages produce files of various formats containing calendar
and diary entries, for display purposes.

@cindex calendar and HTML
  The Calendar HTML commands produce files of HTML code that contain
calendar and diary entries.  Each file applies to one month, and has a
name of the format @file{@var{yyyy}-@var{mm}.html}, where @var{yyyy} and
@var{mm} are the four-digit year and two-digit month, respectively.  The
variable @code{cal-html-directory} specifies the default output
directory for the HTML files.

@vindex cal-html-css-default
  Diary entries enclosed by @code{<} and @code{>} 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 @file{cal.css} in
the directory containing the HTML files (see the value of the variable
@code{cal-html-css-default} for relevant style settings).

@kindex t @r{(Calendar mode)}
@table @kbd
@item H m
Generate a one-month calendar (@code{cal-html-cursor-month}).
@item H y
Generate a calendar file for each month of a year, as well as an index
page (@code{cal-html-cursor-year}).  By default, this command writes
files to a @var{yyyy} subdirectory - if this is altered some hyperlinks
between years will not work.
@end table

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

@cindex calendar and La@TeX{}
  The Calendar La@TeX{} commands produce a buffer of La@TeX{} 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.

@kindex t @r{(Calendar mode)}
@table @kbd
@item t m
Generate a one-month calendar (@code{cal-tex-cursor-month}).
@item t M
Generate a sideways-printing one-month calendar
(@code{cal-tex-cursor-month-landscape}).
@item t d
Generate a one-day calendar
(@code{cal-tex-cursor-day}).
@item t w 1
Generate a one-page calendar for one week
(@code{cal-tex-cursor-week}).
@item t w 2
Generate a two-page calendar for one week
(@code{cal-tex-cursor-week2}).
@item t w 3
Generate an ISO-style calendar for one week
(@code{cal-tex-cursor-week-iso}).
@item t w 4
Generate a calendar for one Monday-starting week
(@code{cal-tex-cursor-week-monday}).
@item t f w
Generate a Filofax-style two-weeks-at-a-glance calendar
(@code{cal-tex-cursor-filofax-2week}).
@item t f W
Generate a Filofax-style one-week-at-a-glance calendar
(@code{cal-tex-cursor-filofax-week}).
@item t y
Generate a calendar for one year
(@code{cal-tex-cursor-year}).
@item t Y
Generate a sideways-printing calendar for one year
(@code{cal-tex-cursor-year-landscape}).
@item t f y
Generate a Filofax-style calendar for one year
(@code{cal-tex-cursor-filofax-year}).
@end table

  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 @code{cal-tex-holidays} is non-@code{nil} (the default),
then the printed calendars show the holidays in @code{calendar-holidays}.
If the variable @code{cal-tex-diary} is non-@code{nil} (the default is
@code{nil}), diary entries are included also (in monthly, filofax, and
iso-week calendars only).  If the variable @code{cal-tex-rules} is
non-@code{nil} (the default is @code{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 @code{cal-tex-preamble-extra} to insert extra
La@TeX{} commands in the preamble of the generated document if you need
to.

@node Holidays
@section Holidays
@cindex holidays

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

@table @kbd
@item h
Display holidays for the selected date
(@code{calendar-cursor-holidays}).
@item Mouse-2 Holidays
Display any holidays for the date you click on.
@item x
462
Mark holidays in the calendar window (@code{calendar-mark-holidays}).
Glenn Morris's avatar
Glenn Morris committed
463 464 465 466
@item u
Unmark calendar window (@code{calendar-unmark}).
@item a
List all holidays for the displayed three months in another window
467
(@code{calendar-list-holidays}).
Glenn Morris's avatar
Glenn Morris committed
468 469 470
@item M-x holidays
List all holidays for three months around today's date in another
window.
471
@item M-x list-holidays
Glenn Morris's avatar
Glenn Morris committed
472 473 474 475 476
List holidays in another window for a specified range of years.
@end table

@kindex h @r{(Calendar mode)}
@findex calendar-cursor-holidays
477
@vindex calendar-view-holidays-initially-flag
Glenn Morris's avatar
Glenn Morris committed
478 479 480 481 482 483 484 485
  To see if any holidays fall on a given date, position point on that
date in the calendar window and use the @kbd{h} command.  Alternatively,
click on that date with @kbd{Mouse-2} and then choose @kbd{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.

@kindex x @r{(Calendar mode)}
486
@findex calendar-mark-holidays
Glenn Morris's avatar
Glenn Morris committed
487 488
@kindex u @r{(Calendar mode)}
@findex calendar-unmark
489
@vindex calendar-mark-holidays-flag
Glenn Morris's avatar
Glenn Morris committed
490 491 492
  To view the distribution of holidays for all the dates shown in the
calendar, use the @kbd{x} command.  This displays the dates that are
holidays in a different face (or places a @samp{*} after these dates, if
493
a color display is not available, or if @code{font-lock-mode} is off).
Glenn Morris's avatar
Glenn Morris committed
494 495 496 497 498 499 500 501 502 503
@iftex
@inforef{Calendar Customizing, calendar-holiday-marker, emacs-xtra}.
@end iftex
@ifnottex
@xref{Calendar Customizing, calendar-holiday-marker}.
@end ifnottex
  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 @kbd{u}, which also
erases any diary marks (@pxref{Diary}).  If the variable
504
@code{calendar-mark-holidays-flag} is non-@code{nil}, creating or
Glenn Morris's avatar
Glenn Morris committed
505 506 507
updating the calendar marks holidays automatically.

@kindex a @r{(Calendar mode)}
508
@findex calendar-list-holidays
Glenn Morris's avatar
Glenn Morris committed
509 510 511 512 513 514 515 516 517
  To get even more detailed information, use the @kbd{a} command, which
displays a separate buffer containing a list of all holidays in the
current three-month range.  You can use @key{SPC} and @key{DEL} in the
calendar window to scroll that list up and down, respectively.

@findex holidays
  The command @kbd{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
518
@code{calendar-view-holidays-initially-flag} is non-@code{nil}, creating
Glenn Morris's avatar
Glenn Morris committed
519 520 521 522 523 524 525 526
the calendar displays holidays in this way.  If you want the list of
holidays centered around a different month, use @kbd{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.

527
@findex list-holidays
528
   The command @kbd{M-x holiday-list} displays the list of holidays for
Glenn Morris's avatar
Glenn Morris committed
529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759
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 @emph{current
practice}, not historical fact.  For example Veteran's Day began in
1919, but is shown in earlier years.

@node Sunrise/Sunset
@section Times of Sunrise and Sunset
@cindex sunrise and sunset

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

@table @kbd
@item S
Display times of sunrise and sunset for the selected date
(@code{calendar-sunrise-sunset}).
@item Mouse-2 Sunrise/sunset
Display times of sunrise and sunset for the date you click on.
@item M-x sunrise-sunset
Display times of sunrise and sunset for today's date.
@item C-u M-x sunrise-sunset
Display times of sunrise and sunset for a specified date.
@end table

@kindex S @r{(Calendar mode)}
@findex calendar-sunrise-sunset
@findex sunrise-sunset
  Within the calendar, to display the @emph{local times} of sunrise and
sunset in the echo area, move point to the date you want, and type
@kbd{S}.  Alternatively, click @kbd{Mouse-2} on the date, then choose
@samp{Sunrise/sunset} from the menu that appears.  The command @kbd{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 @kbd{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 @kbd{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:

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

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

  Your time zone also affects the local time of sunrise and sunset.
Emacs usually gets 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:

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

@noindent
The value of @code{calendar-time-zone} is the number of minutes
difference between your local standard time and Coordinated Universal
Time (Greenwich time).  The values of
@code{calendar-standard-time-zone-name} and
@code{calendar-daylight-time-zone-name} are the abbreviations used in
your time zone.  Emacs displays the times of sunrise and sunset
@emph{corrected for daylight saving time}.  @xref{Daylight Saving},
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 @file{.emacs} file.
And when you install Emacs on a machine, you can create a
@file{default.el} file which sets them properly for the typical location
of most users of that machine.  @xref{Init File}.

@node Lunar Phases
@section Phases of the Moon
@cindex phases of the moon
@cindex moon, phases of

  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.''

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

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

@findex phases-of-moon
  Outside the calendar, use the command @kbd{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 @kbd{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 saving, when appropriate); but if
the variable @code{calendar-time-zone} is void, Coordinated Universal
Time (the Greenwich time zone) is used.  @xref{Daylight Saving}.

@node Other Calendars
@section Conversion To and From Other Calendars

@cindex Gregorian calendar
  The Emacs calendar displayed is @emph{always} the Gregorian calendar,
sometimes called the ``new style'' calendar, which is used in most of
the world today.  However, this calendar did not exist before the
sixteenth century and was not widely used before the eighteenth century;
it did not fully displace the Julian calendar and gain universal
acceptance until the early twentieth century.  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.
@end menu

@node Calendar Systems
@subsection Supported Calendar Systems

@cindex ISO commercial calendar
  The ISO commercial calendar is used largely in Europe.

@cindex Julian calendar
  The Julian calendar, named after Julius Caesar, was the one used in Europe
throughout medieval times, and in many countries up until the nineteenth
century.

@cindex Julian day numbers
@cindex astronomical day numbers
  Astronomers use a simple counting of days elapsed since noon, Monday,
January 1, 4713 B.C. on the Julian calendar.  The number of days elapsed
is called the @dfn{Julian day number} or the @dfn{Astronomical day number}.

@cindex Hebrew calendar
  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.

@cindex Islamic calendar
  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.

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

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

@cindex Coptic calendar
@cindex Ethiopic calendar
  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.

@cindex Persian calendar
  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 that far into the future.

@cindex Chinese calendar
  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.

760 761 762 763 764
@cindex Baha'i calendar
  The Baha'i 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.

Glenn Morris's avatar
Glenn Morris committed
765 766 767 768 769 770 771 772 773 774
@node To Other Calendar
@subsection Converting To Other Calendars

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

@table @kbd
@item Mouse-2  Other calendars
Display the date that you click on, expressed in various other calendars.
@kindex p @r{(Calendar mode)}
775
@findex calendar-iso-print-date
Glenn Morris's avatar
Glenn Morris committed
776 777
@item p c
Display ISO commercial calendar equivalent for selected day
778 779
(@code{calendar-iso-print-date}).
@findex calendar-julian-print-date
Glenn Morris's avatar
Glenn Morris committed
780
@item p j
781 782
Display Julian date for selected day (@code{calendar-julian-print-date}).
@findex calendar-astro-print-day-number
Glenn Morris's avatar
Glenn Morris committed
783 784
@item p a
Display astronomical (Julian) day number for selected day
785 786
(@code{calendar-astro-print-day-number}).
@findex calendar-hebrew-print-date
Glenn Morris's avatar
Glenn Morris committed
787
@item p h
788 789
Display Hebrew date for selected day (@code{calendar-hebrew-print-date}).
@findex calendar-islamic-print-date
Glenn Morris's avatar
Glenn Morris committed
790
@item p i
791 792
Display Islamic date for selected day (@code{calendar-islamic-print-date}).
@findex calendar-french-print-date
Glenn Morris's avatar
Glenn Morris committed
793 794
@item p f
Display French Revolutionary date for selected day
795 796 797 798 799 800
(@code{calendar-french-print-date}).
@findex calendar-bahai-print-date
@item p b
Display Baha'i date for selected day
(@code{calendar-bahai-print-date}).
@findex calendar-chinese-print-date
Glenn Morris's avatar
Glenn Morris committed
801 802
@item p C
Display Chinese date for selected day
803 804
(@code{calendar-chinese-print-date}).
@findex calendar-coptic-print-date
Glenn Morris's avatar
Glenn Morris committed
805 806
@item p k
Display Coptic date for selected day
807 808
(@code{calendar-coptic-print-date}).
@findex calendar-ethiopic-print-date
Glenn Morris's avatar
Glenn Morris committed
809 810
@item p e
Display Ethiopic date for selected day
811 812
(@code{calendar-ethiopic-print-date}).
@findex calendar-persian-print-date
Glenn Morris's avatar
Glenn Morris committed
813 814
@item p p
Display Persian date for selected day
815 816
(@code{calendar-persian-print-date}).
@findex calendar-mayan-print-date
Glenn Morris's avatar
Glenn Morris committed
817
@item p m
818
Display Mayan date for selected day (@code{calendar-mayan-print-date}).
Glenn Morris's avatar
Glenn Morris committed
819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840
@end table

  If you are using X, the easiest way to translate a date into other
calendars is to click on it with @kbd{Mouse-2}, then choose @kbd{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.)

  Otherwise, move point to the date you want to convert, then type the
appropriate command starting with @kbd{p} from the table above.  The
prefix @kbd{p} is a mnemonic for ``print,'' since Emacs ``prints'' the
equivalent date in the echo area.

@node From Other Calendar
@subsection 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.

@kindex g @var{char} @r{(Calendar mode)}
841 842 843 844 845 846 847 848 849 850 851
@findex calendar-iso-goto-date
@findex calendar-iso-goto-week
@findex calendar-julian-goto-date
@findex calendar-astro-goto-day-number
@findex calendar-hebrew-goto-date
@findex calendar-islamic-goto-date
@findex calendar-french-goto-date
@findex calendar-chinese-goto-date
@findex calendar-persian-goto-date
@findex calendar-coptic-goto-date
@findex calendar-ethiopic-goto-date
Glenn Morris's avatar
Glenn Morris committed
852 853 854
@table @kbd
@item g c
Move to a date specified in the ISO commercial calendar
855
(@code{calendar-iso-goto-date}).
Glenn Morris's avatar
Glenn Morris committed
856 857
@item g w
Move to a week specified in the ISO commercial calendar
858
(@code{calendar-iso-goto-week}).
Glenn Morris's avatar
Glenn Morris committed
859 860
@item g j
Move to a date specified in the Julian calendar
861
(@code{calendar-julian-goto-date}).
Glenn Morris's avatar
Glenn Morris committed
862 863
@item g a
Move to a date specified with an astronomical (Julian) day number
864
(@code{calendar-astro-goto-day-number}).
Glenn Morris's avatar
Glenn Morris committed
865 866
@item g h
Move to a date specified in the Hebrew calendar
867
(@code{calendar-hebrew-goto-date}).
Glenn Morris's avatar
Glenn Morris committed
868 869
@item g i
Move to a date specified in the Islamic calendar
870
(@code{calendar-islamic-goto-date}).
Glenn Morris's avatar
Glenn Morris committed
871 872
@item g f
Move to a date specified in the French Revolutionary calendar
873
(@code{calendar-french-goto-date}).
Glenn Morris's avatar
Glenn Morris committed
874 875
@item g C
Move to a date specified in the Chinese calendar
876
(@code{calendar-chinese-goto-date}).
Glenn Morris's avatar
Glenn Morris committed
877 878
@item g p
Move to a date specified in the Persian calendar
879
(@code{calendar-persian-goto-date}).
Glenn Morris's avatar
Glenn Morris committed
880 881
@item g k
Move to a date specified in the Coptic calendar
882
(@code{calendar-coptic-goto-date}).
Glenn Morris's avatar
Glenn Morris committed
883 884
@item g e
Move to a date specified in the Ethiopic calendar
885
(@code{calendar-ethiopic-goto-date}).
Glenn Morris's avatar
Glenn Morris committed
886 887 888 889 890 891 892 893
@end table

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

894
@findex calendar-hebrew-list-yahrzeits
Glenn Morris's avatar
Glenn Morris committed
895 896 897 898
@cindex yahrzeits
  One common question concerning the Hebrew calendar is the computation
of the anniversary of a date of death, called a ``yahrzeit.''  The Emacs
calendar includes a facility for such calculations.  If you are in the
899 900
calendar, the command @kbd{M-x calendar-hebrew-list-yahrzeits} asks you for
a range of years and then displays a list of the yahrzeit dates for those
Glenn Morris's avatar
Glenn Morris committed
901 902 903 904 905 906 907 908 909 910 911 912
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.

@node Mayan Calendar
@subsection Converting from the Mayan Calendar

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

@table @kbd
@item g m l
Move to a date specified by the long count calendar
913
(@code{calendar-mayan-goto-long-count-date}).
Glenn Morris's avatar
Glenn Morris committed
914 915
@item g m n t
Move to the next occurrence of a place in the
916
tzolkin calendar (@code{calendar-mayan-next-tzolkin-date}).
Glenn Morris's avatar
Glenn Morris committed
917 918
@item g m p t
Move to the previous occurrence of a place in the
919
tzolkin calendar (@code{calendar-mayan-previous-tzolkin-date}).
Glenn Morris's avatar
Glenn Morris committed
920 921
@item g m n h
Move to the next occurrence of a place in the
922
haab calendar (@code{calendar-mayan-next-haab-date}).
Glenn Morris's avatar
Glenn Morris committed
923 924
@item g m p h
Move to the previous occurrence of a place in the
925
haab calendar (@code{calendar-mayan-previous-haab-date}).
Glenn Morris's avatar
Glenn Morris committed
926 927
@item g m n c
Move to the next occurrence of a place in the
928
calendar round (@code{calendar-mayan-next-calendar-round-date}).
Glenn Morris's avatar
Glenn Morris committed
929 930
@item g m p c
Move to the previous occurrence of a place in the
931
calendar round (@code{calendar-mayan-previous-calendar-round-date}).
Glenn Morris's avatar
Glenn Morris committed
932 933 934 935 936 937 938 939 940 941 942 943
@end table

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

@display
1 kin = 1 day@ @ @ 1 uinal = 20 kin@ @ @ 1 tun = 18 uinal
1 katun = 20 tun@ @ @ 1 baktun = 20 katun
@end display

@kindex g m @r{(Calendar mode)}
944
@findex calendar-mayan-goto-long-count-date
Glenn Morris's avatar
Glenn Morris committed
945 946 947 948 949 950 951
@noindent
Thus, the long count date 12.16.11.16.6 means 12 baktun, 16 katun, 11
tun, 16 uinal, and 6 kin.  The Emacs calendar can handle Mayan long
count dates as early as 7.17.18.13.3, but no earlier.  When you use the
@kbd{g m l} command, type the Mayan long count date with the baktun,
katun, tun, uinal, and kin separated by periods.

952 953
@findex calendar-mayan-previous-tzolkin-date
@findex calendar-mayan-next-tzolkin-date
Glenn Morris's avatar
Glenn Morris committed
954 955 956 957 958 959 960 961 962
@cindex Mayan tzolkin calendar
  The Mayan tzolkin calendar is a cycle of 260 days formed by a pair of
independent cycles of 13 and 20 days.  Since this cycle repeats
endlessly, Emacs provides commands to move backward and forward to the
previous or next point in the cycle.  Type @kbd{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 @kbd{g m n t}
to go to the next occurrence of a tzolkin date.

963 964
@findex calendar-mayan-previous-haab-date
@findex calendar-mayan-next-haab-date
Glenn Morris's avatar
Glenn Morris committed
965 966 967 968 969 970 971 972 973 974 975
@cindex Mayan haab calendar
  The Mayan haab calendar is a cycle of 365 days arranged as 18 months
of 20 days each, followed a 5-day monthless period.  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
@kbd{g m p h} to go to the previous haab date; Emacs asks you for a haab
date and moves point to the previous occurrence of that date.
Similarly, type @kbd{g m n h} to go to the next occurrence of a haab
date.

@c This is omitted because it is too long for smallbook format.
976 977
@c @findex calendar-mayan-previous-calendar-round-date
@findex calendar-mayan-next-calendar-round-date
Glenn Morris's avatar
Glenn Morris committed
978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002
@cindex Mayan calendar round
  The Maya also used the combination of the tzolkin date and the haab
date.  This combination is a cycle of about 52 years called a
@emph{calendar round}.  If you type @kbd{g m p c}, Emacs asks you for
both a haab and a tzolkin date and then moves point to the previous
occurrence of that combination.  Use @kbd{g m 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{Strict Completion}) whenever it
asks you to type a Mayan name, so you don't have to worry about
spelling.

@node Diary
@section The Diary
@cindex 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 @dfn{diary file} containing a list of events and
their dates.  Then Emacs can automatically pick out and display the
events for today, for the immediate future, or for any specified
date.

  The name of the diary file is specified by the variable
1003 1004
@code{diary-file}; @file{~/diary} is the default.  Here's an example
showing what that file looks like:
Glenn Morris's avatar
Glenn Morris committed
1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020

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

@noindent
1021
This format is essentially the same as the one used by the system's
Juanma Barranquero's avatar
Juanma Barranquero committed
1022
@command{calendar} utility.  This example uses extra spaces to align
1023 1024
the event descriptions of most of the entries.  Such formatting is
purely a matter of taste.
Glenn Morris's avatar
Glenn Morris committed
1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053

  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.

@menu
* Displaying the Diary::   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.
@end menu

@node Displaying the Diary
@subsection 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.

@table @kbd
@item d
Display all diary entries for the selected date
(@code{diary-view-entries}).
@item Mouse-2 Diary
Display all diary entries for the date you click on.
@item s
Display the entire diary file (@code{diary-show-all-entries}).
@item m
Mark all visible dates that have diary entries
1054
(@code{diary-mark-entries}).
Glenn Morris's avatar
Glenn Morris committed
1055 1056
@item u
Unmark the calendar window (@code{calendar-unmark}).
1057
@item M-x diary-print-entries
Glenn Morris's avatar
Glenn Morris committed
1058 1059 1060 1061 1062 1063 1064 1065 1066
Print hard copy of the diary display as it appears.
@item M-x diary
Display all diary entries for today's date.
@item M-x diary-mail-entries
Mail yourself email reminders about upcoming diary entries.
@end table

@kindex d @r{(Calendar mode)}
@findex diary-view-entries
1067
@vindex calendar-view-diary-initially-flag
Glenn Morris's avatar
Glenn Morris committed
1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078
  Displaying the diary entries with @kbd{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 @kbd{d},
it shows all the diary entries for that many successive days.  Thus,
@kbd{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
@kbd{Mouse-2} on the date, and then choose @kbd{Diary entries} from
the menu that appears.  If the variable
1079
@code{calendar-view-diary-initially-flag} is non-@code{nil}, creating the
Glenn Morris's avatar
Glenn Morris committed
1080 1081 1082 1083
calendar lists the diary entries for the current date (provided the
current date is visible).

@kindex m @r{(Calendar mode)}
1084 1085
@findex diary-mark-entries
@vindex calendar-mark-diary-entries-flag
Glenn Morris's avatar
Glenn Morris committed
1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099
  To get a broader view of which days are mentioned in the diary, use
the @kbd{m} command.  This displays the dates that have diary entries in
a different face (or places a @samp{+} after these dates, if display
with multiple faces is not available).
@iftex
@inforef{Calendar Customizing, diary-entry-marker, emacs-xtra}.
@end iftex
@ifnottex
@xref{Calendar Customizing, diary-entry-marker}.
@end ifnottex
  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 @kbd{u}, which also
turns off holiday marks (@pxref{Holidays}).  If the variable
1100
@code{calendar-mark-diary-entries-flag} is non-@code{nil}, creating or
Glenn Morris's avatar
Glenn Morris committed
1101 1102 1103 1104 1105 1106 1107
updating the calendar marks diary dates automatically.

@kindex s @r{(Calendar mode)}
@findex diary-show-all-entries
  To see the full diary file, rather than just some of the entries, use
the @kbd{s} command.

1108 1109 1110 1111 1112 1113 1114
  Display of selected diary entries uses invisible text 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
@emph{as it appears}; this command is @kbd{M-x diary-print-entries}.
It sends the data directly to the printer.  You can customize it
like @code{lpr-region} (@pxref{Printing}).
Glenn Morris's avatar
Glenn Morris committed
1115 1116 1117 1118

@findex diary
  The command @kbd{M-x diary} displays the diary entries for the current
date, independently of the calendar display, and optionally for the next
1119
few days as well; the variable @code{diary-number-of-entries} specifies
Glenn Morris's avatar
Glenn Morris committed
1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209
how many days to include.
@iftex
@inforef{Diary Customizing,, emacs-xtra}.
@end iftex
@ifnottex
@xref{Diary Customizing, number-of-diary-entries}.
@end ifnottex

  If you put @code{(diary)} in your @file{.emacs} file, this
automatically displays a window with the day's diary entries, when you
enter Emacs.  The mode line of the displayed window shows the date and
any holidays that fall on that date.

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

@node Format of Diary File
@subsection The Diary File
@cindex diary file

@vindex diary-file
  Your @dfn{diary file} is a file that records events associated with
particular dates.  The name of the diary file is specified by the
variable @code{diary-file}; @file{~/diary} is the default.  The
@code{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 (@samp{&}) at the beginning of
the entry, before the date.  This has no effect on display of the entry
in the diary window; it affects only marks on dates in the calendar
window.  Nonmarking entries are especially useful for generic entries
that would otherwise mark many different dates.

  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:

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

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

  You can edit the diary entries as they appear in the window, but it is
important to remember that the buffer displayed contains the @emph{entire}
diary file, with portions of it concealed from view.  This means, for
instance, that the @kbd{C-f} (@code{forward-char}) command can put point
at what appears to be the end of the line, but what is in reality the
middle of some concealed line.

  @emph{Be careful when editing the diary entries!}  Inserting
additional lines or adding/deleting characters in the middle of a
visible line cannot cause problems, 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 @kbd{s} (@code{diary-show-all-entries}).

@node Date Formats
@subsection 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,
1210
month, year) and ISO order (year, month, day) as options.
Glenn Morris's avatar
Glenn Morris committed
1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247

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

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

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

  Dates can also have the form @samp{@var{monthname} @var{day}} or
@samp{@var{monthname} @var{day}, @var{year}}, where the month's name can
be spelled in full or abbreviated (with or without a period).  The
preferred abbreviations can be controlled using the variables
@code{calendar-abbrev-length}, @code{calendar-month-abbrev-array}, and
@code{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 @dfn{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, @var{month}, @var{day}, or @var{year} can be a @samp{*};
this matches any month, day, or year, respectively.  Thus, a diary entry
@samp{3/*/*} matches any day in March of any year; so does @samp{march
*}.

1248 1249 1250 1251 1252 1253 1254 1255
@vindex calendar-date-style
@findex calendar-set-date-style
  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 @kbd{M-x calendar-set-date-style} while in the
calendar, or customize the variable @code{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.
Glenn Morris's avatar
Glenn Morris committed
1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269

  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.

@node Adding to Diary
@subsection Commands to Add to the Diary

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

@table @kbd
@item i d
1270
Add a diary entry for the selected date (@code{diary-insert-entry}).
Glenn Morris's avatar
Glenn Morris committed
1271
@item i w
1272
Add a diary entry for the selected day of the week (@code{diary-insert-weekly-entry}).
Glenn Morris's avatar
Glenn Morris committed
1273
@item i m
1274
Add a diary entry for the selected day of the month (@code{diary-insert-monthly-entry}).
Glenn Morris's avatar
Glenn Morris committed
1275
@item i y
1276
Add a diary entry for the selected day of the year (@code{diary-insert-yearly-entry}).
Glenn Morris's avatar
Glenn Morris committed
1277 1278 1279
@end table

@kindex i d @r{(Calendar mode)}
1280
@findex diary-insert-entry
Glenn Morris's avatar
Glenn Morris committed
1281 1282 1283 1284 1285 1286
  You can make a diary entry for a specific date by selecting that date
in the calendar window and typing the @kbd{i d} command.  This command
displays the end of your diary file in another window and inserts the
date; you can then type the rest of the diary entry.

@kindex i w @r{(Calendar mode)}
1287
@findex diary-insert-weekly-entry
Glenn Morris's avatar
Glenn Morris committed
1288
@kindex i m @r{(Calendar mode)}
1289
@findex diary-insert-monthly-entry
Glenn Morris's avatar
Glenn Morris committed
1290
@kindex i y @r{(Calendar mode)}
1291
@findex diary-insert-yearly-entry
Glenn Morris's avatar
Glenn Morris committed
1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307
  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
@kbd{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 @kbd{i m}
command, and type the rest of the entry.  Similarly, you can insert a
yearly diary entry with the @kbd{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, @kbd{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
1308
@code{calendar-redraw} to force an update at any time.
Glenn Morris's avatar
Glenn Morris committed
1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326

@node Special Diary Entries
@subsection Special Diary Entries

  In addition to entries based on calendar dates, the diary file can
contain @dfn{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
@samp{%%} 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:

@table @kbd
@item i a
Add an anniversary diary entry for the selected date
1327
(@code{diary-insert-anniversary-entry}).
Glenn Morris's avatar
Glenn Morris committed
1328 1329
@item i b
Add a block diary entry for the current region
1330
(@code{diary-insert-block-entry}).
Glenn Morris's avatar
Glenn Morris committed
1331 1332
@item i c
Add a cyclic diary entry starting at the date
1333
(@code{diary-insert-cyclic-entry}).
Glenn Morris's avatar
Glenn Morris committed
1334 1335 1336
@end table

@kindex i a @r{(Calendar mode)}
1337
@findex diary-insert-anniversary-entry
Glenn Morris's avatar
Glenn Morris committed
1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350
  If you want to make a diary entry that applies to the anniversary of a
specific date, move point to that date and use the @kbd{i a} command.
This displays the end of your diary file in another window and inserts
the anniversary description; you can then type the rest of the diary
entry.  The entry looks like this:

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

@noindent
This entry applies to October 31 in any year after 1948; @samp{10 31
1351 1352 1353 1354
1948} 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.
Glenn Morris's avatar
Glenn Morris committed
1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366

  A @dfn{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:

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

@noindent
The @samp{6 24 1990} indicates the starting date and the @samp{7 10 1990}
1367 1368
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.)
Glenn Morris's avatar
Glenn Morris committed
1369 1370

@kindex i b @r{(Calendar mode)}
1371
@findex diary-insert-block-entry
Glenn Morris's avatar
Glenn Morris committed
1372 1373 1374 1375 1376 1377
  To insert a block entry, place point and the mark on the two
dates that begin and end the range, and type @kbd{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.

@kindex i c @r{(Calendar mode)}
1378
@findex diary-insert-cyclic-entry
Glenn Morris's avatar
Glenn Morris committed
1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391
   @dfn{Cyclic} diary entries repeat after a fixed interval of days.  To
create one, select the starting date and use the @kbd{i c} command.  The
command prompts for the length of interval, then inserts the entry,
which looks like this:

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

@noindent
This entry applies to March 1, 1990 and every 50th day following;
@samp{3 1 1990} specifies the starting date.  (If you are using the
1392 1393
European or ISO calendar style, the input order of month, day and year
is different.)
Glenn Morris's avatar
Glenn Morris committed
1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407

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

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

  Another sophisticated kind of sexp entry, a @dfn{floating} diary entry,
specifies a regularly occurring event by offsets specified in days,
weeks, and months.  It is comparable to a crontab entry interpreted by
the @code{cron} utility.  Here is a nonmarking, floating diary entry
1408
that applies to the fourth Thursday in November:
Glenn Morris's avatar
Glenn Morris committed
1409 1410 1411

@findex diary-float
@example
1412
&%%(diary-float 11 4 4) American Thanksgiving
Glenn Morris's avatar
Glenn Morris committed
1413 1414 1415 1416 1417
@end example

@noindent
The 11 specifies November (the eleventh month), the 4 specifies Thursday
(the fourth day of the week, where Sunday is numbered zero), and the
1418 1419 1420
second 4 specifies the fourth Thursday (1 would mean ``first,'' 2 would
mean ``second,'' @minus{}2 would mean ``second-to-last,'' and so on).
The month can be a single month or a list of months.  Thus you could change
Glenn Morris's avatar
Glenn Morris committed
1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696
the 11 above to @samp{'(1 2 3)} and have the entry apply to the last
Thursday of January, February, and March.  If the month is @code{t}, the
entry applies to all months of the year.@refill

  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.
@iftex
@inforef{Sexp Diary Entries,, emacs-xtra}.
@end iftex
@ifnottex
@inforef{Sexp Diary Entries}.
@end ifnottex

@node Appointments
@section Appointments
@cindex appointment notification

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

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

@findex appt-activate
  To enable appointment notification, use the command @kbd{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:

@example
Monday
  9:30am Coffee break
 12:00pm Lunch
@end example

@vindex appt-message-warning-time
@noindent
Then on Mondays, you will be reminded at around 9:20am about your
coffee break and at around 11:50am about lunch.  The variable
@code{appt-message-warning-time} specifies how many minutes in advance
to warn you; its default value is 12 (12 minutes).

  You can write times in am/pm style (with @samp{12:00am} standing
for midnight and @samp{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 lines if they are to be recognized.

@vindex appt-display-diary
  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
@code{appt-display-diary} to @code{nil}.  The appointments list is
also updated whenever the diary file is saved.

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

@node Importing Diary
@section Importing and Exporting Diary Entries

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

@vindex diary-outlook-formats
  You can import diary entries from Outlook-generated appointment
messages.  While viewing such a message in Rmail or Gnus, do @kbd{M-x
diary-from-outlook} to import the entry.  You can make this command
recognize additional appointment message formats by customizing the
variable @code{diary-outlook-formats}.

@cindex iCalendar support
  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).

  Importing works for ``ordinary'' (i.e. non-recurring) events, but
(at present) may not work correctly (if at all) for recurring events.
Exporting of diary files into iCalendar files should work correctly
for most diary entries.  This feature is a work in progress, so the
commands may evolve in future.

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

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

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

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

@noindent
You can use an @code{#include} directive to add the import file contents
to the main diary file, if these are different files.
@iftex
@inforef{Fancy Diary Display,, emacs-xtra}.
@end iftex
@ifnottex
@xref{Fancy Diary Display}.
@end ifnottex


@findex icalendar-export-file, icalendar-export-region
  Use @code{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 @code{icalendar-export-region}.
In both cases the result is appended to the target file.

@node Daylight Saving
@section Daylight Saving Time
@cindex 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.

@vindex calendar-daylight-savings-starts
@vindex calendar-daylight-savings-ends
  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:
@code{calendar-daylight-savings-starts} and
@code{calendar-daylight-savings-ends}.

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

@example
(calendar-nth-named-day 2 0 3 year)
(calendar-nth-named-day 1 0 11 year)
@end example

@noindent
That is, the second 0th day (Sunday) of the third month (March) in
the year specified by @code{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
@code{calendar-daylight-savings-starts} to this:

@example
(list 10 1 year)
@end example

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

@vindex calendar-daylight-time-offset
  The variable @code{calendar-daylight-time-offset} specifies the
difference between daylight saving time and standard time, measured in
minutes.  The value for Cambridge, Massachusetts is 60.

@c @vindex calendar-daylight-savings-starts-time  too long!
@vindex calendar-daylight-savings-ends-time
  Finally, the two variables
@code{calendar-daylight-savings-starts-time} and
@code{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.

@node Time Intervals
@section Summing Time Intervals
@cindex time intervals, summing
@cindex summing time intervals
@cindex timeclock

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

@findex timeclock-in
@findex timeclock-out
@findex timeclock-change
@findex timeclock-workday-remaining
@findex timeclock-when-to-leave
  Use the @kbd{M-x timeclock-in} command when you start working on a
project, and @kbd{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 @kbd{M-x
timeclock-change}.

  Once you've collected data from a number of time intervals, you can use
@kbd{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 @kbd{M-x
timeclock-when-to-leave} which will calculate when you're ``done.''

@vindex timeclock-modeline-display
@findex timeclock-modeline-display
  If you want Emacs to display the amount of time ``left'' of your
workday in the mode line, either customize the
@code{timeclock-modeline-display} variable and set its value to
@code{t}, or invoke the @kbd{M-x timeclock-modeline-display} command.

@vindex timeclock-ask-before-exiting
  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, set the value of the variable
@code{timeclock-ask-before-exiting} to @code{nil} (via @kbd{M-x
customize}) to avoid the question; then, only an explicit @kbd{M-x
timeclock-out} or @kbd{M-x timeclock-change} will tell Emacs that the
current interval is over.

@cindex @file{.timelog} file
@vindex timeclock-file
@findex timeclock-reread-log
  The timeclock functions work by accumulating the data in a file
called @file{.timelog} in your home directory.  You can specify a
different name for this file by customizing the variable
@code{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 @kbd{M-x timeclock-reread-log} to update the
data in Emacs from the file.

@ifnottex
@include cal-xtra.texi
@end ifnottex

@ignore
   arch-tag: 4531ef09-9df3-449d-9c52-2b5a4a337f92
@end ignore