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   (run-hooks 'calendar-move-hook))
  50
  51 (defun calendar-forward-month (arg)
  52   "Move the cursor forward ARG months.
  53 Movement is backward if ARG is negative."
  54   (interactive "p")
  55   (calendar-cursor-to-nearest-date)
  56   (let* ((cursor-date (calendar-cursor-to-date t))
  57          (month (extract-calendar-month cursor-date))
  58          (day (extract-calendar-day cursor-date))
  59          (year (extract-calendar-year cursor-date)))
  60     (increment-calendar-month month year arg)
  61     (let ((last (calendar-last-day-of-month month year)))
  62       (if (< last day)
  63         (setq day last)))
  64     ;; Put the new month on the screen, if needed, and go to the new date.
  65     (let ((new-cursor-date (list month day year)))
  66       (if (not (calendar-date-is-visible-p new-cursor-date))
  67           (calendar-other-month month year))
  68       (calendar-cursor-to-visible-date new-cursor-date)))
  69   (run-hooks 'calendar-move-hook))
  70
  71 (defun calendar-forward-year (arg)
  72   "Move the cursor forward by ARG years.
  73 Movement is backward if ARG is negative."
  74   (interactive "p")
  75   (calendar-forward-month (* 12 arg)))
  76
  77 (defun calendar-backward-month (arg)
  78   "Move the cursor backward by ARG months.
  79 Movement is forward if ARG is negative."
  80   (interactive "p")
  81   (calendar-forward-month (- arg)))
  82
  83 (defun calendar-backward-year (arg)
  84   "Move the cursor backward ARG years.
  85 Movement is forward is ARG is negative."
  86   (interactive "p")
  87   (calendar-forward-month (* -12 arg)))
  88
  89 (defun scroll-calendar-left (arg)
  90   "Scroll the displayed calendar left by ARG months.
  91 If ARG is negative the calendar is scrolled right.  Maintains the relative
  92 position of the cursor with respect to the calendar as well as possible."
  93   (interactive "p")
  94   (calendar-cursor-to-nearest-date)
  95   (let ((old-date (calendar-cursor-to-date))
  96         (today (calendar-current-date)))
  97     (if (/= arg 0)
  98         (let ((month displayed-month)
  99               (year displayed-year))
 100           (increment-calendar-month month year arg)
 101           (generate-calendar-window month year)
 102           (calendar-cursor-to-visible-date
 103            (cond
 104             ((calendar-date-is-visible-p old-date) old-date)
 105             ((calendar-date-is-visible-p today) today)
 106             (t (list month 1 year)))))))
 107   (run-hooks 'calendar-move-hook))
 108
 109 (defun scroll-calendar-right (arg)
 110   "Scroll the displayed calendar window right by ARG months.
 111 If ARG is negative the calendar is scrolled left.  Maintains the relative
 112 position of the cursor with respect to the calendar as well as possible."
 113   (interactive "p")
 114   (scroll-calendar-left (- arg)))
 115
 116 (defun scroll-calendar-left-three-months (arg)
 117   "Scroll the displayed calendar window left by 3*ARG months.
 118 If ARG is negative the calendar is scrolled right.  Maintains the relative
 119 position of the cursor with respect to the calendar as well as possible."
 120   (interactive "p")
 121   (scroll-calendar-left (* 3 arg)))
 122
 123 (defun scroll-calendar-right-three-months (arg)
 124   "Scroll the displayed calendar window right by 3*ARG months.
 125 If ARG is negative the calendar is scrolled left.  Maintains the relative
 126 position of the cursor with respect to the calendar as well as possible."
 127   (interactive "p")
 128   (scroll-calendar-left (* -3 arg)))
 129
 130 (defun calendar-cursor-to-nearest-date ()
 131   "Move the cursor to the closest date.
 132 The position of the cursor is unchanged if it is already on a date.
 133 Returns the list (month day year) giving the cursor position."
 134   (let ((date (calendar-cursor-to-date))
 135         (column (current-column)))
 136     (if date
 137         date
 138       (if (> 3 (count-lines (point-min) (point)))
 139           (progn
 140             (goto-line 3)
 141             (move-to-column column)))
 142       (if (not (looking-at "[0-9]"))
 143           (if (and (not (looking-at " *$"))
 144                    (or (< column 25)
 145                        (and (> column 27)
 146                             (< column 50))
 147                        (and (> column 52)
 148                             (< column 75))))
 149               (progn
 150                 (re-search-forward "[0-9]" nil t)
 151                 (backward-char 1))
 152             (re-search-backward "[0-9]" nil t)))
 153       (calendar-cursor-to-date))))
 154
 155 (defun calendar-forward-day (arg)
 156   "Move the cursor forward ARG days.
 157 Moves backward if ARG is negative."
 158   (interactive "p")
 159   (if (/= 0 arg)
 160       (let*
 161           ((cursor-date (calendar-cursor-to-date))
 162            (cursor-date (if cursor-date
 163                             cursor-date
 164                           (if (> arg 0) (setq arg (1- arg)))
 165                           (calendar-cursor-to-nearest-date)))
 166            (new-cursor-date
 167             (calendar-gregorian-from-absolute
 168              (+ (calendar-absolute-from-gregorian cursor-date) arg)))
 169            (new-display-month (extract-calendar-month new-cursor-date))
 170            (new-display-year (extract-calendar-year new-cursor-date)))
 171         ;; Put the new month on the screen, if needed, and go to the new date.
 172         (if (not (calendar-date-is-visible-p new-cursor-date))
 173             (calendar-other-month new-display-month new-display-year))
 174         (calendar-cursor-to-visible-date new-cursor-date)))
 175   (run-hooks 'calendar-move-hook))
 176
 177 (defun calendar-backward-day (arg)
 178   "Move the cursor back ARG days.
 179 Moves forward if ARG is negative."
 180   (interactive "p")
 181   (calendar-forward-day (- arg)))
 182
 183 (defun calendar-forward-week (arg)
 184   "Move the cursor forward ARG weeks.
 185 Moves backward if ARG is negative."
 186   (interactive "p")
 187   (calendar-forward-day (* arg 7)))
 188
 189 (defun calendar-backward-week (arg)
 190   "Move the cursor back ARG weeks.
 191 Moves forward if ARG is negative."
 192   (interactive "p")
 193   (calendar-forward-day (* arg -7)))
 194
 195 (defun calendar-beginning-of-week (arg)
 196   "Move the cursor back ARG calendar-week-start-day's."
 197   (interactive "p")
 198   (calendar-cursor-to-nearest-date)
 199   (let ((day (calendar-day-of-week (calendar-cursor-to-date))))
 200     (calendar-backward-day
 201      (if (= day calendar-week-start-day)
 202          (* 7 arg)
 203        (+ (mod (- day calendar-week-start-day) 7)
 204           (* 7 (1- arg)))))))
 205
 206 (defun calendar-end-of-week (arg)
 207   "Move the cursor forward ARG calendar-week-start-day+6's."
 208   (interactive "p")
 209   (calendar-cursor-to-nearest-date)
 210   (let ((day (calendar-day-of-week (calendar-cursor-to-date))))
 211     (calendar-forward-day
 212      (if (= day (mod (1- calendar-week-start-day) 7))
 213          (* 7 arg)
 214        (+ (- 6 (mod (- day calendar-week-start-day) 7))
 215           (* 7 (1- arg)))))))
 216
 217 (defun calendar-beginning-of-month (arg)
 218   "Move the cursor backward ARG month beginnings."
 219   (interactive "p")
 220   (calendar-cursor-to-nearest-date)
 221   (let* ((date (calendar-cursor-to-date))
 222          (month (extract-calendar-month date))
 223          (day (extract-calendar-day date))
 224          (year (extract-calendar-year date)))
 225     (if (= day 1)
 226         (calendar-backward-month arg)
 227       (calendar-cursor-to-visible-date (list month 1 year))
 228       (calendar-backward-month (1- arg)))))
 229
 230 (defun calendar-end-of-month (arg)
 231   "Move the cursor forward ARG month ends."
 232   (interactive "p")
 233   (calendar-cursor-to-nearest-date)
 234   (let* ((date (calendar-cursor-to-date))
 235          (month (extract-calendar-month date))
 236          (day (extract-calendar-day date))
 237          (year (extract-calendar-year date))
 238          (last-day (calendar-last-day-of-month month year)))
 239     (if (/= day last-day)
 240         (progn
 241           (calendar-cursor-to-visible-date (list month last-day year))
 242           (setq arg (1- arg))))
 243     (increment-calendar-month month year arg)
 244     (let ((last-day (list
 245                      month
 246                      (calendar-last-day-of-month month year)
 247                      year)))
 248       (if (not (calendar-date-is-visible-p last-day))
 249           (calendar-other-month month year)
 250       (calendar-cursor-to-visible-date last-day))))
 251   (run-hooks 'calendar-move-hook))
 252
 253 (defun calendar-beginning-of-year (arg)
 254   "Move the cursor backward ARG year beginnings."
 255   (interactive "p")
 256   (calendar-cursor-to-nearest-date)
 257   (let* ((date (calendar-cursor-to-date))
 258          (month (extract-calendar-month date))
 259          (day (extract-calendar-day date))
 260          (year (extract-calendar-year date))
 261          (jan-first (list 1 1 year))
 262          (calendar-move-hook nil))
 263     (if (and (= day 1) (= 1 month))
 264         (calendar-backward-month (* 12 arg))
 265       (if (and (= arg 1)
 266                (calendar-date-is-visible-p jan-first))
 267           (calendar-cursor-to-visible-date jan-first)
 268         (calendar-other-month 1 (- year (1- arg))))))
 269   (run-hooks 'calendar-move-hook))
 270
 271 (defun calendar-end-of-year (arg)
 272   "Move the cursor forward ARG year beginnings."
 273   (interactive "p")
 274   (calendar-cursor-to-nearest-date)
 275   (let* ((date (calendar-cursor-to-date))
 276          (month (extract-calendar-month date))
 277          (day (extract-calendar-day date))
 278          (year (extract-calendar-year date))
 279          (dec-31 (list 12 31 year))
 280          (calendar-move-hook nil))
 281     (if (and (= day 31) (= 12 month))
 282         (calendar-forward-month (* 12 arg))
 283       (if (and (= arg 1)
 284                (calendar-date-is-visible-p dec-31))
 285           (calendar-cursor-to-visible-date dec-31)
 286         (calendar-other-month 12 (- year (1- arg)))
 287         (calendar-cursor-to-visible-date (list 12 31 displayed-year)))))
 288   (run-hooks 'calendar-move-hook))
 289
 290 (defun calendar-cursor-to-visible-date (date)
 291   "Move the cursor to DATE that is on the screen."
 292   (let* ((month (extract-calendar-month date))
 293          (day (extract-calendar-day date))
 294          (year (extract-calendar-year date))
 295          (first-of-month-weekday (calendar-day-of-week (list month 1 year))))
 296     (goto-line (+ 3
 297                   (/ (+ day  -1
 298                         (mod
 299                          (- (calendar-day-of-week (list month 1 year))
 300                             calendar-week-start-day)
 301                          7))
 302                      7)))
 303     (move-to-column (+ 6
 304                        (* 25
 305                           (1+ (calendar-interval
 306                                displayed-month displayed-year month year)))
 307                        (* 3 (mod
 308                              (- (calendar-day-of-week date)
 309                                 calendar-week-start-day)
 310                              7))))))
 311
 312 (defun calendar-goto-date (date)
 313   "Move cursor to DATE."
 314   (interactive (list (calendar-read-date)))
 315   (let ((month (extract-calendar-month date))
 316         (year (extract-calendar-year date)))
 317     (if (not (calendar-date-is-visible-p date))
 318         (calendar-other-month
 319          (if (and (= month 1) (= year 1))
 320              2
 321            month)
 322          year)))
 323   (calendar-cursor-to-visible-date date)
 324   (run-hooks 'calendar-move-hook))
 325
 326 (provide 'cal-move)
 327
 328 ;;; cal-move.el ends here