code.delx.au - gnu-emacs/blob - lisp/calendar/cal-move.el

   1 ;;; cal-move.el --- calendar functions for movement in the calendar
   2
   3 ;; Copyright (C) 1995 Free Software Foundation, Inc.
   4
   5 ;; Author: Edward M. Reingold <reingold@cs.uiuc.edu>
   6 ;; Keywords: calendar
   7 ;; Human-Keywords: calendar
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 2, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  24 ;; Boston, MA 02111-1307, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; This collection of functions implements movement in the calendar for
  29 ;; calendar.el.
  30
  31 ;; Comments, corrections, and improvements should be sent to
  32 ;;  Edward M. Reingold               Department of Computer Science
  33 ;;  (217) 333-6733                   University of Illinois at Urbana-Champaign
  34 ;;  reingold@cs.uiuc.edu             1304 West Springfield Avenue
  35 ;;                                   Urbana, Illinois 61801
  36
  37 ;;; Code:
  38
  39 (require 'calendar)
  40
  41 (defun calendar-goto-today ()
  42   "Reposition the calendar window so the current date is visible."
  43   (interactive)
  44   (let ((today (calendar-current-date)));; The date might have changed.
  45     (if (not (calendar-date-is-visible-p today))
  46         (generate-calendar-window)
  47       (update-calendar-mode-line)
  48       (calendar-cursor-to-visible-date today))))
  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
  69 (defun calendar-forward-year (arg)
  70   "Move the cursor forward by ARG years.
  71 Movement is backward if ARG is negative."
  72   (interactive "p")
  73   (calendar-forward-month (* 12 arg)))
  74
  75 (defun calendar-backward-month (arg)
  76   "Move the cursor backward by ARG months.
  77 Movement is forward if ARG is negative."
  78   (interactive "p")
  79   (calendar-forward-month (- arg)))
  80
  81 (defun calendar-backward-year (arg)
  82   "Move the cursor backward ARG years.
  83 Movement is forward is ARG is negative."
  84   (interactive "p")
  85   (calendar-forward-month (* -12 arg)))
  86
  87 (defun scroll-calendar-left (arg)
  88   "Scroll the displayed calendar left by ARG months.
  89 If ARG is negative the calendar is scrolled right.  Maintains the relative
  90 position of the cursor with respect to the calendar as well as possible."
  91   (interactive "p")
  92   (calendar-cursor-to-nearest-date)
  93   (let ((old-date (calendar-cursor-to-date))
  94         (today (calendar-current-date)))
  95     (if (/= arg 0)
  96         (progn
  97           (increment-calendar-month displayed-month displayed-year arg)
  98           (generate-calendar-window displayed-month displayed-year)
  99           (calendar-cursor-to-visible-date
 100            (cond
 101             ((calendar-date-is-visible-p old-date) old-date)
 102             ((calendar-date-is-visible-p today) today)
 103             (t (list displayed-month 1 displayed-year))))))))
 104
 105 (defun scroll-calendar-right (arg)
 106   "Scroll the displayed calendar window right by ARG months.
 107 If ARG is negative the calendar is scrolled left.  Maintains the relative
 108 position of the cursor with respect to the calendar as well as possible."
 109   (interactive "p")
 110   (scroll-calendar-left (- arg)))
 111
 112 (defun scroll-calendar-left-three-months (arg)
 113   "Scroll the displayed calendar window left by 3*ARG months.
 114 If ARG is negative the calendar is scrolled right.  Maintains the relative
 115 position of the cursor with respect to the calendar as well as possible."
 116   (interactive "p")
 117   (scroll-calendar-left (* 3 arg)))
 118
 119 (defun scroll-calendar-right-three-months (arg)
 120   "Scroll the displayed calendar window right by 3*ARG months.
 121 If ARG is negative the calendar is scrolled left.  Maintains the relative
 122 position of the cursor with respect to the calendar as well as possible."
 123   (interactive "p")
 124   (scroll-calendar-left (* -3 arg)))
 125
 126 (defun calendar-cursor-to-nearest-date ()
 127   "Move the cursor to the closest date.
 128 The position of the cursor is unchanged if it is already on a date.
 129 Returns the list (month day year) giving the cursor position."
 130   (let ((date (calendar-cursor-to-date))
 131         (column (current-column)))
 132     (if date
 133         date
 134       (if (> 3 (count-lines (point-min) (point)))
 135           (progn
 136             (goto-line 3)
 137             (move-to-column column)))
 138       (if (not (looking-at "[0-9]"))
 139           (if (and (not (looking-at " *$"))
 140                    (or (< column 25)
 141                        (and (> column 27)
 142                             (< column 50))
 143                        (and (> column 52)
 144                             (< column 75))))
 145               (progn
 146                 (re-search-forward "[0-9]" nil t)
 147                 (backward-char 1))
 148             (re-search-backward "[0-9]" nil t)))
 149       (calendar-cursor-to-date))))
 150
 151 (defun calendar-forward-day (arg)
 152   "Move the cursor forward ARG days.
 153 Moves backward if ARG is negative."
 154   (interactive "p")
 155   (if (/= 0 arg)
 156       (let*
 157           ((cursor-date (calendar-cursor-to-date))
 158            (cursor-date (if cursor-date
 159                             cursor-date
 160                           (if (> arg 0) (setq arg (1- arg)))
 161                           (calendar-cursor-to-nearest-date)))
 162            (new-cursor-date
 163             (calendar-gregorian-from-absolute
 164              (+ (calendar-absolute-from-gregorian cursor-date) arg)))
 165            (new-display-month (extract-calendar-month new-cursor-date))
 166            (new-display-year (extract-calendar-year new-cursor-date)))
 167         ;; Put the new month on the screen, if needed, and go to the new date.
 168         (if (not (calendar-date-is-visible-p new-cursor-date))
 169             (calendar-other-month new-display-month new-display-year))
 170         (calendar-cursor-to-visible-date new-cursor-date))))
 171
 172 (defun calendar-backward-day (arg)
 173   "Move the cursor back ARG days.
 174 Moves forward if ARG is negative."
 175   (interactive "p")
 176   (calendar-forward-day (- arg)))
 177
 178 (defun calendar-forward-week (arg)
 179   "Move the cursor forward ARG weeks.
 180 Moves backward if ARG is negative."
 181   (interactive "p")
 182   (calendar-forward-day (* arg 7)))
 183
 184 (defun calendar-backward-week (arg)
 185   "Move the cursor back ARG weeks.
 186 Moves forward if ARG is negative."
 187   (interactive "p")
 188   (calendar-forward-day (* arg -7)))
 189
 190 (defun calendar-beginning-of-week (arg)
 191   "Move the cursor back ARG calendar-week-start-day's."
 192   (interactive "p")
 193   (calendar-cursor-to-nearest-date)
 194   (let ((day (calendar-day-of-week (calendar-cursor-to-date))))
 195     (calendar-backward-day
 196      (if (= day calendar-week-start-day)
 197          (* 7 arg)
 198        (+ (mod (- day calendar-week-start-day) 7)
 199           (* 7 (1- arg)))))))
 200
 201 (defun calendar-end-of-week (arg)
 202   "Move the cursor forward ARG calendar-week-start-day+6's."
 203   (interactive "p")
 204   (calendar-cursor-to-nearest-date)
 205   (let ((day (calendar-day-of-week (calendar-cursor-to-date))))
 206     (calendar-forward-day
 207      (if (= day (mod (1- calendar-week-start-day) 7))
 208          (* 7 arg)
 209        (+ (- 6 (mod (- day calendar-week-start-day) 7))
 210           (* 7 (1- arg)))))))
 211
 212 (defun calendar-beginning-of-month (arg)
 213   "Move the cursor backward ARG month beginnings."
 214   (interactive "p")
 215   (calendar-cursor-to-nearest-date)
 216   (let* ((date (calendar-cursor-to-date))
 217          (month (extract-calendar-month date))
 218          (day (extract-calendar-day date))
 219          (year (extract-calendar-year date)))
 220     (if (= day 1)
 221         (calendar-backward-month arg)
 222       (calendar-cursor-to-visible-date (list month 1 year))
 223       (calendar-backward-month (1- arg)))))
 224
 225 (defun calendar-end-of-month (arg)
 226   "Move the cursor forward ARG month ends."
 227   (interactive "p")
 228   (calendar-cursor-to-nearest-date)
 229   (let* ((date (calendar-cursor-to-date))
 230          (month (extract-calendar-month date))
 231          (day (extract-calendar-day date))
 232          (year (extract-calendar-year date))
 233          (last-day (calendar-last-day-of-month month year)))
 234     (if (/= day last-day)
 235         (progn
 236           (calendar-cursor-to-visible-date (list month last-day year))
 237           (setq arg (1- arg))))
 238     (increment-calendar-month month year arg)
 239     (let ((last-day (list
 240                      month
 241                      (calendar-last-day-of-month month year)
 242                      year)))
 243       (if (not (calendar-date-is-visible-p last-day))
 244           (calendar-other-month month year)
 245       (calendar-cursor-to-visible-date last-day)))))
 246
 247 (defun calendar-beginning-of-year (arg)
 248   "Move the cursor backward ARG year beginnings."
 249   (interactive "p")
 250   (calendar-cursor-to-nearest-date)
 251   (let* ((date (calendar-cursor-to-date))
 252          (month (extract-calendar-month date))
 253          (day (extract-calendar-day date))
 254          (year (extract-calendar-year date))
 255          (jan-first (list 1 1 year)))
 256     (if (and (= day 1) (= 1 month))
 257         (calendar-backward-month (* 12 arg))
 258       (if (and (= arg 1)
 259                (calendar-date-is-visible-p jan-first))
 260           (calendar-cursor-to-visible-date jan-first)
 261         (calendar-other-month 1 (- year (1- arg)))))))
 262
 263 (defun calendar-end-of-year (arg)
 264   "Move the cursor forward ARG year beginnings."
 265   (interactive "p")
 266   (calendar-cursor-to-nearest-date)
 267   (let* ((date (calendar-cursor-to-date))
 268          (month (extract-calendar-month date))
 269          (day (extract-calendar-day date))
 270          (year (extract-calendar-year date))
 271          (dec-31 (list 12 31 year)))
 272     (if (and (= day 31) (= 12 month))
 273         (calendar-forward-month (* 12 arg))
 274       (if (and (= arg 1)
 275                (calendar-date-is-visible-p dec-31))
 276           (calendar-cursor-to-visible-date dec-31)
 277         (calendar-other-month 12 (- year (1- arg)))
 278         (calendar-cursor-to-visible-date (list 12 31 displayed-year))))))
 279
 280 (defun calendar-cursor-to-visible-date (date)
 281   "Move the cursor to DATE that is on the screen."
 282   (let* ((month (extract-calendar-month date))
 283          (day (extract-calendar-day date))
 284          (year (extract-calendar-year date))
 285          (first-of-month-weekday (calendar-day-of-week (list month 1 year))))
 286     (goto-line (+ 3
 287                   (/ (+ day  -1
 288                         (mod
 289                          (- (calendar-day-of-week (list month 1 year))
 290                             calendar-week-start-day)
 291                          7))
 292                      7)))
 293     (move-to-column (+ 6
 294                        (* 25
 295                           (1+ (calendar-interval
 296                                displayed-month displayed-year month year)))
 297                        (* 3 (mod
 298                              (- (calendar-day-of-week date)
 299                                 calendar-week-start-day)
 300                              7))))))
 301
 302 (defun calendar-goto-date (date)
 303   "Move cursor to DATE."
 304   (interactive (list (calendar-read-date)))
 305   (let ((month (extract-calendar-month date))
 306         (year (extract-calendar-year date)))
 307     (if (not (calendar-date-is-visible-p date))
 308         (calendar-other-month
 309          (if (and (= month 1) (= year 1))
 310              2
 311            month)
 312          year)))
 313   (calendar-cursor-to-visible-date date))
 314
 315 (provide 'cal-move)
 316
 317 ;;; cal-move.el ends here