lisp/register.el

   1 ;;; register.el --- register commands for Emacs      -*- lexical-binding: t; -*-
   2
   3 ;; Copyright (C) 1985, 1993-1994, 2001-2015 Free Software Foundation,
   4 ;; Inc.
   5
   6 ;; Maintainer: emacs-devel@gnu.org
   7 ;; Keywords: internal
   8 ;; Package: emacs
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software: you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation, either version 3 of the License, or
  15 ;; (at your option) any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;; This package of functions emulates and somewhat extends the venerable
  28 ;; TECO's `register' feature, which permits you to save various useful
  29 ;; pieces of buffer state to named variables.  The entry points are
  30 ;; documented in the Emacs user's manual.
  31
  32 (eval-when-compile (require 'cl-lib))
  33
  34 ;;; Code:
  35
  36 (cl-defstruct
  37   (registerv (:constructor nil)
  38              (:constructor registerv--make (&optional data print-func
  39                                                       jump-func insert-func))
  40              (:copier nil)
  41              (:type vector)
  42              :named)
  43   (data        nil :read-only t)
  44   (print-func  nil :read-only t)
  45   (jump-func   nil :read-only t)
  46   (insert-func nil :read-only t))
  47
  48 (cl-defun registerv-make (data &key print-func jump-func insert-func)
  49   "Create a register value object.
  50
  51 DATA can be any value.
  52 PRINT-FUNC if provided controls how `list-registers' and
  53 `view-register' print the register.  It should be a function
  54 receiving one argument DATA and print text that completes
  55 this sentence:
  56   Register X contains [TEXT PRINTED BY PRINT-FUNC]
  57 JUMP-FUNC if provided, controls how `jump-to-register' jumps to the register.
  58 INSERT-FUNC if provided, controls how `insert-register' insert the register.
  59 They both receive DATA as argument."
  60   (registerv--make data print-func jump-func insert-func))
  61
  62 (defvar register-alist nil
  63   "Alist of elements (NAME . CONTENTS), one for each Emacs register.
  64 NAME is a character (a number).  CONTENTS is a string, number, marker, list
  65 or a struct returned by `registerv-make'.
  66 A list of strings represents a rectangle.
  67 A list of the form (file . FILE-NAME) represents the file named FILE-NAME.
  68 A list of the form (file-query FILE-NAME POSITION) represents
  69  position POSITION in the file named FILE-NAME, but query before
  70  visiting it.
  71 A list of the form (WINDOW-CONFIGURATION POSITION)
  72  represents a saved window configuration plus a saved value of point.
  73 A list of the form (FRAME-CONFIGURATION POSITION)
  74  represents a saved frame configuration plus a saved value of point.")
  75
  76 (defgroup register nil
  77   "Register commands."
  78   :group 'convenience
  79   :version "24.3")
  80
  81 (defcustom register-separator nil
  82   "Register containing the text to put between collected texts, or nil if none.
  83
  84 When collecting text with \\[append-to-register] (or \\[prepend-to-register]),
  85 contents of this register is added to the beginning (or end, respectively)
  86 of the marked text."
  87   :group 'register
  88   :type '(choice (const :tag "None" nil)
  89                  (character :tag "Use register" :value ?+)))
  90
  91 (defcustom register-preview-delay 1
  92   "If non-nil, time to wait in seconds before popping up a preview window.
  93 If nil, do not show register previews, unless `help-char' (or a member of
  94 `help-event-list') is pressed."
  95   :version "24.4"
  96   :type '(choice number (const :tag "No preview unless requested" nil))
  97   :group 'register)
  98
  99 (defun get-register (register)
 100   "Return contents of Emacs register named REGISTER, or nil if none."
 101   (cdr (assq register register-alist)))
 102
 103 (defun set-register (register value)
 104   "Set contents of Emacs register named REGISTER to VALUE.  Returns VALUE.
 105 See the documentation of the variable `register-alist' for possible VALUEs."
 106   (let ((aelt (assq register register-alist)))
 107     (if aelt
 108         (setcdr aelt value)
 109       (push (cons register value) register-alist))
 110     value))
 111
 112 (defun register-describe-oneline (c)
 113   "One-line description of register C."
 114   (let ((d (replace-regexp-in-string
 115             "\n[ \t]*" " "
 116             (with-output-to-string (describe-register-1 c)))))
 117     (if (string-match "Register.+? contains \\(?:an? \\|the \\)?" d)
 118         (substring d (match-end 0))
 119       d)))
 120
 121 (defun register-preview-default (r)
 122   "Default function for the variable `register-preview-function'."
 123   (format "%s: %s\n"
 124           (single-key-description (car r))
 125           (register-describe-oneline (car r))))
 126
 127 (defvar register-preview-function #'register-preview-default
 128   "Function to format a register for previewing.
 129 Takes one argument, a cons (NAME . CONTENTS) as found in `register-alist'.
 130 Returns a string.")
 131
 132 (defun register-preview (buffer &optional show-empty)
 133   "Pop up a window to show register preview in BUFFER.
 134 If SHOW-EMPTY is non-nil show the window even if no registers.
 135 Format of each entry is controlled by the variable `register-preview-function'."
 136   (when (or show-empty (consp register-alist))
 137     (with-current-buffer-window
 138      buffer
 139      (cons 'display-buffer-below-selected
 140            '((window-height . fit-window-to-buffer)))
 141      nil
 142      (with-current-buffer standard-output
 143        (setq cursor-in-non-selected-windows nil)
 144        (insert (mapconcat register-preview-function register-alist ""))))))
 145
 146 (defun register-read-with-preview (prompt)
 147   "Read and return a register name, possibly showing existing registers.
 148 Prompt with the string PROMPT.  If `register-alist' and
 149 `register-preview-delay' are both non-nil, display a window
 150 listing existing registers after `register-preview-delay' seconds.
 151 If `help-char' (or a member of `help-event-list') is pressed,
 152 display such a window regardless."
 153   (let* ((buffer "*Register Preview*")
 154          (timer (when (numberp register-preview-delay)
 155                   (run-with-timer register-preview-delay nil
 156                                   (lambda ()
 157                                     (unless (get-buffer-window buffer)
 158                                       (register-preview buffer))))))
 159          (help-chars (cl-loop for c in (cons help-char help-event-list)
 160                               when (not (get-register c))
 161                               collect c)))
 162     (unwind-protect
 163         (progn
 164           (while (memq (read-event (propertize prompt 'face 'minibuffer-prompt))
 165                        help-chars)
 166             (unless (get-buffer-window buffer)
 167               (register-preview buffer 'show-empty)))
 168           (if (characterp last-input-event) last-input-event
 169             (error "Non-character input-event")))
 170       (and (timerp timer) (cancel-timer timer))
 171       (let ((w (get-buffer-window buffer)))
 172         (and (window-live-p w) (delete-window w)))
 173       (and (get-buffer buffer) (kill-buffer buffer)))))
 174
 175 (defun point-to-register (register &optional arg)
 176   "Store current location of point in register REGISTER.
 177 With prefix argument, store current frame configuration.
 178 Use \\[jump-to-register] to go to that location or restore that configuration.
 179 Argument is a character, naming the register.
 180
 181 Interactively, reads the register using `register-read-with-preview'."
 182   (interactive (list (register-read-with-preview "Point to register: ")
 183                      current-prefix-arg))
 184   ;; Turn the marker into a file-ref if the buffer is killed.
 185   (add-hook 'kill-buffer-hook 'register-swap-out nil t)
 186   (set-register register
 187                 (if arg (list (current-frame-configuration) (point-marker))
 188                   (point-marker))))
 189
 190 (defun window-configuration-to-register (register &optional _arg)
 191   "Store the window configuration of the selected frame in register REGISTER.
 192 Use \\[jump-to-register] to restore the configuration.
 193 Argument is a character, naming the register.
 194
 195 Interactively, reads the register using `register-read-with-preview'."
 196   (interactive (list (register-read-with-preview
 197                       "Window configuration to register: ")
 198                      current-prefix-arg))
 199   ;; current-window-configuration does not include the value
 200   ;; of point in the current buffer, so record that separately.
 201   (set-register register (list (current-window-configuration) (point-marker))))
 202
 203 ;; It has had the optional arg for ages, but never used it.
 204 (set-advertised-calling-convention 'window-configuration-to-register
 205                                    '(register) "24.4")
 206
 207 (defun frame-configuration-to-register (register &optional _arg)
 208   "Store the window configuration of all frames in register REGISTER.
 209 Use \\[jump-to-register] to restore the configuration.
 210 Argument is a character, naming the register.
 211
 212 Interactively, reads the register using `register-read-with-preview'."
 213   (interactive (list (register-read-with-preview
 214                       "Frame configuration to register: ")
 215                      current-prefix-arg))
 216   ;; current-frame-configuration does not include the value
 217   ;; of point in the current buffer, so record that separately.
 218   (set-register register (list (current-frame-configuration) (point-marker))))
 219
 220 ;; It has had the optional arg for ages, but never used it.
 221 (set-advertised-calling-convention 'frame-configuration-to-register
 222                                    '(register) "24.4")
 223
 224 (make-obsolete 'frame-configuration-to-register 'frameset-to-register' "24.4")
 225
 226 (defalias 'register-to-point 'jump-to-register)
 227 (defun jump-to-register (register &optional delete)
 228   "Move point to location stored in a register.
 229 If the register contains a file name, find that file.
 230 \(To put a file name in a register, you must use `set-register'.)
 231 If the register contains a window configuration (one frame) or a frameset
 232 \(all frames), restore that frame or all frames accordingly.
 233 First argument is a character, naming the register.
 234 Optional second arg non-nil (interactively, prefix argument) says to
 235 delete any existing frames that the frameset doesn't mention.
 236 \(Otherwise, these frames are iconified.)
 237
 238 Interactively, reads the register using `register-read-with-preview'."
 239   (interactive (list (register-read-with-preview "Jump to register: ")
 240                      current-prefix-arg))
 241   (let ((val (get-register register)))
 242     (cond
 243      ((registerv-p val)
 244       (cl-assert (registerv-jump-func val) nil
 245               "Don't know how to jump to register %s"
 246               (single-key-description register))
 247       (funcall (registerv-jump-func val) (registerv-data val)))
 248      ((and (consp val) (frame-configuration-p (car val)))
 249       (set-frame-configuration (car val) (not delete))
 250       (goto-char (cadr val)))
 251      ((and (consp val) (window-configuration-p (car val)))
 252       (set-window-configuration (car val))
 253       (goto-char (cadr val)))
 254      ((markerp val)
 255       (or (marker-buffer val)
 256           (error "That register's buffer no longer exists"))
 257       (switch-to-buffer (marker-buffer val))
 258       (goto-char val))
 259      ((and (consp val) (eq (car val) 'file))
 260       (find-file (cdr val)))
 261      ((and (consp val) (eq (car val) 'file-query))
 262       (or (find-buffer-visiting (nth 1 val))
 263           (y-or-n-p (format "Visit file %s again? " (nth 1 val)))
 264           (error "Register access aborted"))
 265       (find-file (nth 1 val))
 266       (goto-char (nth 2 val)))
 267      (t
 268       (error "Register doesn't contain a buffer position or configuration")))))
 269
 270 (defun register-swap-out ()
 271   "Turn markers into file-query references when a buffer is killed."
 272   (and buffer-file-name
 273        (dolist (elem register-alist)
 274          (and (markerp (cdr elem))
 275               (eq (marker-buffer (cdr elem)) (current-buffer))
 276               (setcdr elem
 277                       (list 'file-query
 278                             buffer-file-name
 279                             (marker-position (cdr elem))))))))
 280
 281 (defun number-to-register (number register)
 282   "Store a number in a register.
 283 Two args, NUMBER and REGISTER (a character, naming the register).
 284 If NUMBER is nil, a decimal number is read from the buffer starting
 285 at point, and point moves to the end of that number.
 286 Interactively, NUMBER is the prefix arg (none means nil).
 287
 288 Interactively, reads the register using `register-read-with-preview'."
 289   (interactive (list current-prefix-arg
 290                      (register-read-with-preview "Number to register: ")))
 291   (set-register register
 292                 (if number
 293                     (prefix-numeric-value number)
 294                   (if (looking-at "\\s-*-?[0-9]+")
 295                       (progn
 296                         (goto-char (match-end 0))
 297                         (string-to-number (match-string 0)))
 298                     0))))
 299
 300 (defun increment-register (prefix register)
 301   "Augment contents of REGISTER.
 302 Interactively, PREFIX is in raw form.
 303
 304 If REGISTER contains a number, add `prefix-numeric-value' of
 305 PREFIX to it.
 306
 307 If REGISTER is empty or if it contains text, call
 308 `append-to-register' with `delete-flag' set to PREFIX.
 309
 310 Interactively, reads the register using `register-read-with-preview'."
 311   (interactive (list current-prefix-arg
 312                      (register-read-with-preview "Increment register: ")))
 313   (let ((register-val (get-register register)))
 314     (cond
 315      ((numberp register-val)
 316       (let ((number (prefix-numeric-value prefix)))
 317         (set-register register (+ number register-val))))
 318      ((or (not register-val) (stringp register-val))
 319       (append-to-register register (region-beginning) (region-end) prefix))
 320      (t (error "Register does not contain a number or text")))))
 321
 322 (defun view-register (register)
 323   "Display what is contained in register named REGISTER.
 324 The Lisp value REGISTER is a character.
 325
 326 Interactively, reads the register using `register-read-with-preview'."
 327   (interactive (list (register-read-with-preview "View register: ")))
 328   (let ((val (get-register register)))
 329     (if (null val)
 330         (message "Register %s is empty" (single-key-description register))
 331       (with-output-to-temp-buffer "*Output*"
 332         (describe-register-1 register t)))))
 333
 334 (defun list-registers ()
 335   "Display a list of nonempty registers saying briefly what they contain."
 336   (interactive)
 337   (let ((list (copy-sequence register-alist)))
 338     (setq list (sort list (lambda (a b) (< (car a) (car b)))))
 339     (with-output-to-temp-buffer "*Output*"
 340       (dolist (elt list)
 341         (when (get-register (car elt))
 342           (describe-register-1 (car elt))
 343           (terpri))))))
 344
 345 (defun describe-register-1 (register &optional verbose)
 346   (princ "Register ")
 347   (princ (single-key-description register))
 348   (princ " contains ")
 349   (let ((val (get-register register)))
 350     (cond
 351      ((registerv-p val)
 352       (if (registerv-print-func val)
 353           (funcall (registerv-print-func val) (registerv-data val))
 354         (princ "[UNPRINTABLE CONTENTS].")))
 355
 356      ((numberp val)
 357       (princ val))
 358
 359      ((markerp val)
 360       (let ((buf (marker-buffer val)))
 361         (if (null buf)
 362             (princ "a marker in no buffer")
 363           (princ "a buffer position:\n    buffer ")
 364           (princ (buffer-name buf))
 365           (princ ", position ")
 366           (princ (marker-position val)))))
 367
 368      ((and (consp val) (window-configuration-p (car val)))
 369       (princ "a window configuration."))
 370
 371      ((and (consp val) (frame-configuration-p (car val)))
 372       (princ "a frame configuration."))
 373
 374      ((and (consp val) (eq (car val) 'file))
 375       (princ "the file ")
 376       (prin1 (cdr val))
 377       (princ "."))
 378
 379      ((and (consp val) (eq (car val) 'file-query))
 380       (princ "a file-query reference:\n    file ")
 381       (prin1 (car (cdr val)))
 382       (princ ",\n    position ")
 383       (princ (car (cdr (cdr val))))
 384       (princ "."))
 385
 386      ((consp val)
 387       (if verbose
 388           (progn
 389             (princ "the rectangle:\n")
 390             (while val
 391               (princ "    ")
 392               (princ (car val))
 393               (terpri)
 394               (setq val (cdr val))))
 395         (princ "a rectangle starting with ")
 396         (princ (car val))))
 397
 398      ((stringp val)
 399       (setq val (copy-sequence val))
 400       (if (eq yank-excluded-properties t)
 401           (set-text-properties 0 (length val) nil val)
 402         (remove-list-of-text-properties 0 (length val)
 403                                         yank-excluded-properties val))
 404       (if verbose
 405           (progn
 406             (princ "the text:\n")
 407             (princ val))
 408         (cond
 409          ;; Extract first N characters starting with first non-whitespace.
 410          ((string-match (format "[^ \t\n].\\{,%d\\}"
 411                                 ;; Deduct 6 for the spaces inserted below.
 412                                 (min 20 (max 0 (- (window-width) 6))))
 413                         val)
 414           (princ "text starting with\n    ")
 415           (princ (match-string 0 val)))
 416          ((string-match "^[ \t\n]+$" val)
 417           (princ "whitespace"))
 418          (t
 419           (princ "the empty string")))))
 420      (t
 421       (princ "Garbage:\n")
 422       (if verbose (prin1 val))))))
 423
 424 (defun insert-register (register &optional arg)
 425   "Insert contents of register REGISTER.  (REGISTER is a character.)
 426 Normally puts point before and mark after the inserted text.
 427 If optional second arg is non-nil, puts mark before and point after.
 428 Interactively, second arg is non-nil if prefix arg is supplied.
 429
 430 Interactively, reads the register using `register-read-with-preview'."
 431   (interactive (progn
 432                  (barf-if-buffer-read-only)
 433                  (list (register-read-with-preview "Insert register: ")
 434                        current-prefix-arg)))
 435   (push-mark)
 436   (let ((val (get-register register)))
 437     (cond
 438      ((registerv-p val)
 439       (cl-assert (registerv-insert-func val) nil
 440               "Don't know how to insert register %s"
 441               (single-key-description register))
 442       (funcall (registerv-insert-func val) (registerv-data val)))
 443      ((consp val)
 444       (insert-rectangle val))
 445      ((stringp val)
 446       (insert-for-yank val))
 447      ((numberp val)
 448       (princ val (current-buffer)))
 449      ((and (markerp val) (marker-position val))
 450       (princ (marker-position val) (current-buffer)))
 451      (t
 452       (error "Register does not contain text"))))
 453   (if (not arg) (exchange-point-and-mark)))
 454
 455 (defun copy-to-register (register start end &optional delete-flag region)
 456   "Copy region into register REGISTER.
 457 With prefix arg, delete as well.
 458 Called from program, takes five args: REGISTER, START, END, DELETE-FLAG,
 459 and REGION.  START and END are buffer positions indicating what to copy.
 460 The optional argument REGION if non-nil, indicates that we're not just
 461 copying some text between START and END, but we're copying the region.
 462
 463 Interactively, reads the register using `register-read-with-preview'."
 464   (interactive (list (register-read-with-preview "Copy to register: ")
 465                      (region-beginning)
 466                      (region-end)
 467                      current-prefix-arg
 468                      t))
 469   (set-register register (if region
 470                              (funcall region-extract-function delete-flag)
 471                            (prog1 (filter-buffer-substring start end)
 472                              (if delete-flag (delete-region start end)))))
 473   (setq deactivate-mark t)
 474   (cond (delete-flag)
 475         ((called-interactively-p 'interactive)
 476          (indicate-copied-region))))
 477
 478 (defun append-to-register (register start end &optional delete-flag)
 479   "Append region to text in register REGISTER.
 480 With prefix arg, delete as well.
 481 Called from program, takes four args: REGISTER, START, END and DELETE-FLAG.
 482 START and END are buffer positions indicating what to append.
 483
 484 Interactively, reads the register using `register-read-with-preview'."
 485   (interactive (list (register-read-with-preview "Append to register: ")
 486                      (region-beginning)
 487                      (region-end)
 488                      current-prefix-arg))
 489   (let ((reg (get-register register))
 490         (text (filter-buffer-substring start end))
 491         (separator (and register-separator (get-register register-separator))))
 492     (set-register
 493      register (cond ((not reg) text)
 494                     ((stringp reg) (concat reg separator text))
 495                     (t (error "Register does not contain text")))))
 496   (setq deactivate-mark t)
 497   (cond (delete-flag
 498          (delete-region start end))
 499         ((called-interactively-p 'interactive)
 500          (indicate-copied-region))))
 501
 502 (defun prepend-to-register (register start end &optional delete-flag)
 503   "Prepend region to text in register REGISTER.
 504 With prefix arg, delete as well.
 505 Called from program, takes four args: REGISTER, START, END and DELETE-FLAG.
 506 START and END are buffer positions indicating what to prepend.
 507
 508 Interactively, reads the register using `register-read-with-preview'."
 509   (interactive (list (register-read-with-preview "Prepend to register: ")
 510                      (region-beginning)
 511                      (region-end)
 512                      current-prefix-arg))
 513   (let ((reg (get-register register))
 514         (text (filter-buffer-substring start end))
 515         (separator (and register-separator (get-register register-separator))))
 516     (set-register
 517      register (cond ((not reg) text)
 518                     ((stringp reg) (concat text separator reg))
 519                     (t (error "Register does not contain text")))))
 520   (setq deactivate-mark t)
 521   (cond (delete-flag
 522          (delete-region start end))
 523         ((called-interactively-p 'interactive)
 524          (indicate-copied-region))))
 525
 526 (defun copy-rectangle-to-register (register start end &optional delete-flag)
 527   "Copy rectangular region into register REGISTER.
 528 With prefix arg, delete as well.
 529 To insert this register in the buffer, use \\[insert-register].
 530
 531 Called from a program, takes four args: REGISTER, START, END and DELETE-FLAG.
 532 START and END are buffer positions giving two corners of rectangle.
 533
 534 Interactively, reads the register using `register-read-with-preview'."
 535   (interactive (list (register-read-with-preview
 536                       "Copy rectangle to register: ")
 537                      (region-beginning)
 538                      (region-end)
 539                      current-prefix-arg))
 540   (let ((rectangle (if delete-flag
 541                        (delete-extract-rectangle start end)
 542                      (extract-rectangle start end))))
 543     (set-register register rectangle)
 544     (when (and (null delete-flag)
 545                (called-interactively-p 'interactive))
 546       (setq deactivate-mark t)
 547       (indicate-copied-region (length (car rectangle))))))
 548
 549 (provide 'register)
 550 ;;; register.el ends here