lisp/calendar/cal-move.el

   1 ;;; cal-move.el --- calendar functions for movement in the calendar
   2
   3 ;; Copyright (C) 1995, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
   4 ;;   Free Software Foundation, Inc.
   5
   6 ;; Author: Edward M. Reingold <reingold@cs.uiuc.edu>
   7 ;; Maintainer: Glenn Morris <rgm@gnu.org>
   8 ;; Keywords: calendar
   9 ;; Human-Keywords: calendar
  10
  11 ;; This file is part of GNU Emacs.
  12
  13 ;; GNU Emacs is free software; you can redistribute it and/or modify
  14 ;; it under the terms of the GNU General Public License as published by
  15 ;; the Free Software Foundation; either version 3, or (at your option)
  16 ;; any later version.
  17
  18 ;; GNU Emacs is distributed in the hope that it will be useful,
  19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 ;; GNU General Public License for more details.
  22
  23 ;; You should have received a copy of the GNU General Public License
  24 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  25 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  26 ;; Boston, MA 02110-1301, USA.
  27
  28 ;;; Commentary:
  29
  30 ;; This collection of functions implements movement in the calendar for
  31 ;; calendar.el.
  32
  33 ;;; Code:
  34
  35 (defvar displayed-month)
  36 (defvar displayed-year)
  37
  38 (require 'calendar)
  39
  40 (defun calendar-goto-today ()
  41   "Reposition the calendar window so the current date is visible."
  42   (interactive)
  43   (let ((today (calendar-current-date)));; The date might have changed.
  44     (if (not (calendar-date-is-visible-p today))
  45         (generate-calendar-window)
  46       (update-calendar-mode-line)
  47       (calendar-cursor-to-visible-date today)))
  48   (run-hooks 'calendar-move-hook))
  49
  50 (defun calendar-forward-month (arg)
  51   "Move the cursor forward ARG months.
  52 Movement is backward if ARG is negative."
  53   (interactive "p")
  54   (calendar-cursor-to-nearest-date)
  55   (let* ((cursor-date (calendar-cursor-to-date t))
  56          (month (extract-calendar-month cursor-date))
  57          (day (extract-calendar-day cursor-date))
  58          (year (extract-calendar-year cursor-date)))
  59     (increment-calendar-month month year arg)
  60     (let ((last (calendar-last-day-of-month month year)))
  61       (if (< last day)
  62         (setq day last)))
  63     ;; Put the new month on the screen, if needed, and go to the new date.
  64     (let ((new-cursor-date (list month day year)))
  65       (if (not (calendar-date-is-visible-p new-cursor-date))
  66           (calendar-other-month month year))
  67       (calendar-cursor-to-visible-date new-cursor-date)))
  68   (run-hooks 'calendar-move-hook))
  69
  70 (defun calendar-forward-year (arg)
  71   "Move the cursor forward by ARG years.
  72 Movement is backward if ARG is negative."
  73   (interactive "p")
  74   (calendar-forward-month (* 12 arg)))
  75
  76 (defun calendar-backward-month (arg)
  77   "Move the cursor backward by ARG months.
  78 Movement is forward if ARG is negative."
  79   (interactive "p")
  80   (calendar-forward-month (- arg)))
  81
  82 (defun calendar-backward-year (arg)
  83   "Move the cursor backward ARG years.
  84 Movement is forward is ARG is negative."
  85   (interactive "p")
  86   (calendar-forward-month (* -12 arg)))
  87
  88 (defun calendar-scroll-left (&optional arg event)
  89   "Scroll the displayed calendar left by ARG months.
  90 If ARG is negative the calendar is scrolled right.  Maintains the relative
  91 position of the cursor with respect to the calendar as well as possible."
  92   (interactive (list (prefix-numeric-value current-prefix-arg)
  93                      last-nonmenu-event))
  94   (unless arg (setq arg 1))
  95   (save-selected-window
  96     (select-window (posn-window (event-start event)))
  97     (calendar-cursor-to-nearest-date)
  98     (let ((old-date (calendar-cursor-to-date))
  99           (today (calendar-current-date)))
 100       (if (/= arg 0)
 101           (let ((month displayed-month)
 102                 (year displayed-year))
 103             (increment-calendar-month month year arg)
 104             (generate-calendar-window month year)
 105             (calendar-cursor-to-visible-date
 106              (cond
 107               ((calendar-date-is-visible-p old-date) old-date)
 108               ((calendar-date-is-visible-p today) today)
 109               (t (list month 1 year)))))))
 110     (run-hooks 'calendar-move-hook)))
 111
 112 (defun calendar-scroll-right (&optional arg event)
 113   "Scroll the displayed calendar window right by ARG months.
 114 If ARG is negative the calendar is scrolled left.  Maintains the relative
 115 position of the cursor with respect to the calendar as well as possible."
 116   (interactive (list (prefix-numeric-value current-prefix-arg)
 117                      last-nonmenu-event))
 118   (calendar-scroll-left (- (or arg 1)) event))
 119
 120 (defun calendar-scroll-left-three-months (arg)
 121   "Scroll the displayed calendar window left by 3*ARG months.
 122 If ARG is negative the calendar is scrolled right.  Maintains the relative
 123 position of the cursor with respect to the calendar as well as possible."
 124   (interactive "p")
 125   (calendar-scroll-left (* 3 arg)))
 126
 127 (defun calendar-scroll-right-three-months (arg)
 128   "Scroll the displayed calendar window right by 3*ARG months.
 129 If ARG is negative the calendar is scrolled left.  Maintains the relative
 130 position of the cursor with respect to the calendar as well as possible."
 131   (interactive "p")
 132   (calendar-scroll-left (* -3 arg)))
 133
 134 (defun calendar-cursor-to-nearest-date ()
 135   "Move the cursor to the closest date.
 136 The position of the cursor is unchanged if it is already on a date.
 137 Returns the list (month day year) giving the cursor position."
 138   (let ((date (calendar-cursor-to-date))
 139         (column (current-column)))
 140     (if date
 141         date
 142       (if (> 3 (count-lines (point-min) (point)))
 143           (progn
 144             (goto-line 3)
 145             (move-to-column column)))
 146       (if (not (looking-at "[0-9]"))
 147           (if (and (not (looking-at " *$"))
 148                    (or (< column 25)
 149                        (and (> column 27)
 150                             (< column 50))
 151                        (and (> column 52)
 152                             (< column 75))))
 153               (progn
 154                 (re-search-forward "[0-9]" nil t)
 155                 (backward-char 1))
 156             (re-search-backward "[0-9]" nil t)))
 157       (calendar-cursor-to-date))))
 158
 159 (defun calendar-forward-day (arg)
 160   "Move the cursor forward ARG days.
 161 Moves backward if ARG is negative."
 162   (interactive "p")
 163   (if (/= 0 arg)
 164       (let*
 165           ((cursor-date (calendar-cursor-to-date))
 166            (cursor-date (if cursor-date
 167                             cursor-date
 168                           (if (> arg 0) (setq arg (1- arg)))
 169                           (calendar-cursor-to-nearest-date)))
 170            (new-cursor-date
 171             (calendar-gregorian-from-absolute
 172              (+ (calendar-absolute-from-gregorian cursor-date) arg)))
 173            (new-display-month (extract-calendar-month new-cursor-date))
 174            (new-display-year (extract-calendar-year new-cursor-date)))
 175         ;; Put the new month on the screen, if needed, and go to the new date.
 176         (if (not (calendar-date-is-visible-p new-cursor-date))
 177             (calendar-other-month new-display-month new-display-year))
 178         (calendar-cursor-to-visible-date new-cursor-date)))
 179   (run-hooks 'calendar-move-hook))
 180
 181 (defun calendar-backward-day (arg)
 182   "Move the cursor back ARG days.
 183 Moves forward if ARG is negative."
 184   (interactive "p")
 185   (calendar-forward-day (- arg)))
 186
 187 (defun calendar-forward-week (arg)
 188   "Move the cursor forward ARG weeks.
 189 Moves backward if ARG is negative."
 190   (interactive "p")
 191   (calendar-forward-day (* arg 7)))
 192
 193 (defun calendar-backward-week (arg)
 194   "Move the cursor back ARG weeks.
 195 Moves forward if ARG is negative."
 196   (interactive "p")
 197   (calendar-forward-day (* arg -7)))
 198
 199 (defun calendar-beginning-of-week (arg)
 200   "Move the cursor back ARG calendar-week-start-day's."
 201   (interactive "p")
 202   (calendar-cursor-to-nearest-date)
 203   (let ((day (calendar-day-of-week (calendar-cursor-to-date))))
 204     (calendar-backward-day
 205      (if (= day calendar-week-start-day)
 206          (* 7 arg)
 207        (+ (mod (- day calendar-week-start-day) 7)
 208           (* 7 (1- arg)))))))
 209
 210 (defun calendar-end-of-week (arg)
 211   "Move the cursor forward ARG calendar-week-start-day+6's."
 212   (interactive "p")
 213   (calendar-cursor-to-nearest-date)
 214   (let ((day (calendar-day-of-week (calendar-cursor-to-date))))
 215     (calendar-forward-day
 216      (if (= day (mod (1- calendar-week-start-day) 7))
 217          (* 7 arg)
 218        (+ (- 6 (mod (- day calendar-week-start-day) 7))
 219           (* 7 (1- arg)))))))
 220
 221 (defun calendar-beginning-of-month (arg)
 222   "Move the cursor backward ARG month beginnings."
 223   (interactive "p")
 224   (calendar-cursor-to-nearest-date)
 225   (let* ((date (calendar-cursor-to-date))
 226          (month (extract-calendar-month date))
 227          (day (extract-calendar-day date))
 228          (year (extract-calendar-year date)))
 229     (if (= day 1)
 230         (calendar-backward-month arg)
 231       (calendar-cursor-to-visible-date (list month 1 year))
 232       (calendar-backward-month (1- arg)))))
 233
 234 (defun calendar-end-of-month (arg)
 235   "Move the cursor forward ARG month ends."
 236   (interactive "p")
 237   (calendar-cursor-to-nearest-date)
 238   (let* ((date (calendar-cursor-to-date))
 239          (month (extract-calendar-month date))
 240          (day (extract-calendar-day date))
 241          (year (extract-calendar-year date))
 242          (last-day (calendar-last-day-of-month month year)))
 243     (if (/= day last-day)
 244         (progn
 245           (calendar-cursor-to-visible-date (list month last-day year))
 246           (setq arg (1- arg))))
 247     (increment-calendar-month month year arg)
 248     (let ((last-day (list
 249                      month
 250                      (calendar-last-day-of-month month year)
 251                      year)))
 252       (if (not (calendar-date-is-visible-p last-day))
 253           (calendar-other-month month year)
 254       (calendar-cursor-to-visible-date last-day))))
 255   (run-hooks 'calendar-move-hook))
 256
 257 (defun calendar-beginning-of-year (arg)
 258   "Move the cursor backward ARG year beginnings."
 259   (interactive "p")
 260   (calendar-cursor-to-nearest-date)
 261   (let* ((date (calendar-cursor-to-date))
 262          (month (extract-calendar-month date))
 263          (day (extract-calendar-day date))
 264          (year (extract-calendar-year date))
 265          (jan-first (list 1 1 year))
 266          (calendar-move-hook nil))
 267     (if (and (= day 1) (= 1 month))
 268         (calendar-backward-month (* 12 arg))
 269       (if (and (= arg 1)
 270                (calendar-date-is-visible-p jan-first))
 271           (calendar-cursor-to-visible-date jan-first)
 272         (calendar-other-month 1 (- year (1- arg)))
 273         (calendar-cursor-to-visible-date (list 1 1 displayed-year)))))
 274   (run-hooks 'calendar-move-hook))
 275
 276 (defun calendar-end-of-year (arg)
 277   "Move the cursor forward ARG year beginnings."
 278   (interactive "p")
 279   (calendar-cursor-to-nearest-date)
 280   (let* ((date (calendar-cursor-to-date))
 281          (month (extract-calendar-month date))
 282          (day (extract-calendar-day date))
 283          (year (extract-calendar-year date))
 284          (dec-31 (list 12 31 year))
 285          (calendar-move-hook nil))
 286     (if (and (= day 31) (= 12 month))
 287         (calendar-forward-month (* 12 arg))
 288       (if (and (= arg 1)
 289                (calendar-date-is-visible-p dec-31))
 290           (calendar-cursor-to-visible-date dec-31)
 291         (calendar-other-month 12 (+ year (1- arg)))
 292         (calendar-cursor-to-visible-date (list 12 31 displayed-year)))))
 293   (run-hooks 'calendar-move-hook))
 294
 295 (defun calendar-cursor-to-visible-date (date)
 296   "Move the cursor to DATE that is on the screen."
 297   (let* ((month (extract-calendar-month date))
 298          (day (extract-calendar-day date))
 299          (year (extract-calendar-year date))
 300          (first-of-month-weekday (calendar-day-of-week (list month 1 year))))
 301     (goto-line (+ 3
 302                   (/ (+ day  -1
 303                         (mod
 304                          (- (calendar-day-of-week (list month 1 year))
 305                             calendar-week-start-day)
 306                          7))
 307                      7)))
 308     (move-to-column (+ 6
 309                        (* 25
 310                           (1+ (calendar-interval
 311                                displayed-month displayed-year month year)))
 312                        (* 3 (mod
 313                              (- (calendar-day-of-week date)
 314                                 calendar-week-start-day)
 315                              7))))))
 316
 317 (defun calendar-goto-date (date)
 318   "Move cursor to DATE."
 319   (interactive (list (calendar-read-date)))
 320   (let ((month (extract-calendar-month date))
 321         (year (extract-calendar-year date)))
 322     (if (not (calendar-date-is-visible-p date))
 323         (calendar-other-month
 324          (if (and (= month 1) (= year 1))
 325              2
 326            month)
 327          year)))
 328   (calendar-cursor-to-visible-date date)
 329   (run-hooks 'calendar-move-hook))
 330
 331 (defun calendar-goto-day-of-year (year day &optional noecho)
 332   "Move cursor to YEAR, DAY number; echo DAY/YEAR unless NOECHO is t.
 333 Negative DAY counts backward from end of year."
 334   (interactive
 335    (let* ((year (calendar-read
 336                  "Year (>0): "
 337                  (lambda (x) (> x 0))
 338                  (int-to-string (extract-calendar-year
 339                                  (calendar-current-date)))))
 340           (last (if (calendar-leap-year-p year) 366 365))
 341           (day (calendar-read
 342                 (format "Day number (+/- 1-%d): " last)
 343                 '(lambda (x) (and (<= 1 (abs x)) (<= (abs x) last))))))
 344      (list year day)))
 345   (calendar-goto-date
 346    (calendar-gregorian-from-absolute
 347     (if (< 0 day)
 348         (+ -1 day (calendar-absolute-from-gregorian (list 1 1 year)))
 349       (+ 1 day (calendar-absolute-from-gregorian (list 12 31 year))))))
 350   (or noecho (calendar-print-day-of-year)))
 351
 352 ;; Backward compatibility.
 353 (define-obsolete-function-alias
 354   'scroll-calendar-left 'calendar-scroll-left "23.1")
 355 (define-obsolete-function-alias
 356   'scroll-calendar-right 'calendar-scroll-right "23.1")
 357 (define-obsolete-function-alias
 358   'scroll-calendar-left-three-months 'calendar-scroll-left-three-months "23.1")
 359 (define-obsolete-function-alias
 360   'scroll-calendar-right-three-months 'calendar-scroll-right-three-months "23.1")
 361
 362 (provide 'cal-move)
 363
 364 ;; arch-tag: d0883c46-7e16-4914-8ff8-8f67e699b781
 365 ;;; cal-move.el ends here