lisp/register.el

   1 ;;; register.el --- register commands for Emacs      -*- lexical-binding: t; -*-
   2
   3 ;; Copyright (C) 1985, 1993-1994, 2001-2014 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
  85 `append-to-register' (resp. `prepend-to-register') contents of
  86 this register is added to the beginning (resp. end) of the marked
  87 text."
  88   :group 'register
  89   :type '(choice (const :tag "None" nil)
  90                  (character :tag "Use register" :value ?+)))
  91
  92 (defcustom register-preview-delay 1
  93   "If non-nil, time to wait in seconds before popping up a preview window.
  94 If nil, do not show register previews, unless `help-char' (or a member of
  95 `help-event-list') is pressed."
  96   :version "24.4"
  97   :type '(choice number (const :tag "No preview unless requested" nil))
  98   :group 'register)
  99
 100 (defun get-register (register)
 101   "Return contents of Emacs register named REGISTER, or nil if none."
 102   (cdr (assq register register-alist)))
 103
 104 (defun set-register (register value)
 105   "Set contents of Emacs register named REGISTER to VALUE.  Returns VALUE.
 106 See the documentation of the variable `register-alist' for possible VALUEs."
 107   (let ((aelt (assq register register-alist)))
 108     (if aelt
 109         (setcdr aelt value)
 110       (push (cons register value) register-alist))
 111     value))
 112
 113 (defun register-describe-oneline (c)
 114   "One-line description of register C."
 115   (let ((d (replace-regexp-in-string
 116             "\n[ \t]*" " "
 117             (with-output-to-string (describe-register-1 c)))))
 118     (if (string-match "Register.+? contains \\(?:an? \\|the \\)?" d)
 119         (substring d (match-end 0))
 120       d)))
 121
 122 (defun register-preview-default (r)
 123   "Default function for the variable `register-preview-function'."
 124   (format "%s %s\n"
 125           (concat (single-key-description (car r)) ":")
 126           (register-describe-oneline (car r))))
 127
 128 (defvar register-preview-function #'register-preview-default
 129   "Function to format a register for previewing.
 130 Takes one argument, a cons (NAME . CONTENTS) as found in `register-alist'.
 131 Returns a string.")
 132
 133 (defun register-preview (buffer &optional show-empty)
 134   "Pop up a window to show register preview in BUFFER.
 135 If SHOW-EMPTY is non-nil show the window even if no registers.
 136 Format of each entry is controlled by the variable `register-preview-function'."
 137   (when (or show-empty (consp register-alist))
 138     (with-temp-buffer-window
 139      buffer
 140      (cons 'display-buffer-below-selected
 141            '((window-height . fit-window-to-buffer)))
 142      nil
 143      (with-current-buffer standard-output
 144        (setq cursor-in-non-selected-windows nil)
 145        (insert (mapconcat register-preview-function register-alist ""))))))
 146
 147 (defun register-read-with-preview (prompt)
 148   "Read and return a register name, possibly showing existing registers.
 149 Prompt with the string PROMPT.  If `register-alist' and
 150 `register-preview-delay' are both non-nil, display a window
 151 listing existing registers after `register-preview-delay' seconds.
 152 If `help-char' (or a member of `help-event-list') is pressed,
 153 display such a window regardless."
 154   (let* ((buffer "*Register Preview*")
 155          (timer (when (numberp register-preview-delay)
 156                   (run-with-timer register-preview-delay nil
 157                                   (lambda ()
 158                                     (unless (get-buffer-window buffer)
 159                                       (register-preview buffer))))))
 160          (help-chars (cl-loop for c in (cons help-char help-event-list)
 161                               when (not (get-register c))
 162                               collect c)))
 163     (unwind-protect
 164         (progn
 165           (while (memq (read-event (propertize prompt 'face 'minibuffer-prompt))
 166                        help-chars)
 167             (unless (get-buffer-window buffer)
 168               (register-preview buffer 'show-empty)))
 169           (if (characterp last-input-event) last-input-event
 170             (error "Non-character input-event")))
 171       (and (timerp timer) (cancel-timer timer))
 172       (let ((w (get-buffer-window buffer)))
 173         (and (window-live-p w) (delete-window w)))
 174       (and (get-buffer buffer) (kill-buffer buffer)))))
 175
 176 (defun point-to-register (register &optional arg)
 177   "Store current location of point in register REGISTER.
 178 With prefix argument, store current frame configuration.
 179 Use \\[jump-to-register] to go to that location or restore that configuration.
 180 Argument is a character, naming the register.
 181
 182 Interactively, reads the register using `register-read-with-preview'."
 183   (interactive (list (register-read-with-preview "Point to register: ")
 184                      current-prefix-arg))
 185   ;; Turn the marker into a file-ref if the buffer is killed.
 186   (add-hook 'kill-buffer-hook 'register-swap-out nil t)
 187   (set-register register
 188                 (if arg (list (current-frame-configuration) (point-marker))
 189                   (point-marker))))
 190
 191 (defun window-configuration-to-register (register &optional _arg)
 192   "Store the window configuration of the selected frame in register REGISTER.
 193 Use \\[jump-to-register] to restore the configuration.
 194 Argument is a character, naming the register.
 195
 196 Interactively, reads the register using `register-read-with-preview'."
 197   (interactive (list (register-read-with-preview
 198                       "Window configuration to register: ")
 199                      current-prefix-arg))
 200   ;; current-window-configuration does not include the value
 201   ;; of point in the current buffer, so record that separately.
 202   (set-register register (list (current-window-configuration) (point-marker))))
 203
 204 ;; It has had the optional arg for ages, but never used it.
 205 (set-advertised-calling-convention 'window-configuration-to-register
 206                                    '(register) "24.4")
 207
 208 (defun frame-configuration-to-register (register &optional _arg)
 209   "Store the window configuration of all frames in register REGISTER.
 210 Use \\[jump-to-register] to restore the configuration.
 211 Argument is a character, naming the register.
 212
 213 Interactively, reads the register using `register-read-with-preview'."
 214   (interactive (list (register-read-with-preview
 215                       "Frame configuration to register: ")
 216                      current-prefix-arg))
 217   ;; current-frame-configuration does not include the value
 218   ;; of point in the current buffer, so record that separately.
 219   (set-register register (list (current-frame-configuration) (point-marker))))
 220
 221 ;; It has had the optional arg for ages, but never used it.
 222 (set-advertised-calling-convention 'frame-configuration-to-register
 223                                    '(register) "24.4")
 224
 225 (defalias 'register-to-point 'jump-to-register)
 226 (defun jump-to-register (register &optional delete)
 227   "Move point to location stored in a register.
 228 If the register contains a file name, find that file.
 229 \(To put a file name in a register, you must use `set-register'.)
 230 If the register contains a window configuration (one frame) or a frameset
 231 \(all frames), restore that frame or all frames accordingly.
 232 First argument is a character, naming the register.
 233 Optional second arg non-nil (interactively, prefix argument) says to
 234 delete any existing frames that the frameset doesn't mention.
 235 \(Otherwise, these frames are iconified.)
 236
 237 Interactively, reads the register using `register-read-with-preview'."
 238   (interactive (list (register-read-with-preview "Jump to register: ")
 239                      current-prefix-arg))
 240   (let ((val (get-register register)))
 241     (cond
 242      ((registerv-p val)
 243       (cl-assert (registerv-jump-func val) nil
 244               "Don't know how to jump to register %s"
 245               (single-key-description register))
 246       (funcall (registerv-jump-func val) (registerv-data val)))
 247      ((and (consp val) (frame-configuration-p (car val)))
 248       (set-frame-configuration (car val) (not delete))
 249       (goto-char (cadr val)))
 250      ((and (consp val) (window-configuration-p (car val)))
 251       (set-window-configuration (car val))
 252       (goto-char (cadr val)))
 253      ((markerp val)
 254       (or (marker-buffer val)
 255           (error "That register's buffer no longer exists"))
 256       (switch-to-buffer (marker-buffer val))
 257       (goto-char val))
 258      ((and (consp val) (eq (car val) 'file))
 259       (find-file (cdr val)))
 260      ((and (consp val) (eq (car val) 'file-query))
 261       (or (find-buffer-visiting (nth 1 val))
 262           (y-or-n-p (format "Visit file %s again? " (nth 1 val)))
 263           (error "Register access aborted"))
 264       (find-file (nth 1 val))
 265       (goto-char (nth 2 val)))
 266      (t
 267       (error "Register doesn't contain a buffer position or configuration")))))
 268
 269 (defun register-swap-out ()
 270   "Turn markers into file-query references when a buffer is killed."
 271   (and buffer-file-name
 272        (dolist (elem register-alist)
 273          (and (markerp (cdr elem))
 274               (eq (marker-buffer (cdr elem)) (current-buffer))
 275               (setcdr elem
 276                       (list 'file-query
 277                             buffer-file-name
 278                             (marker-position (cdr elem))))))))
 279
 280 (defun number-to-register (number register)
 281   "Store a number in a register.
 282 Two args, NUMBER and REGISTER (a character, naming the register).
 283 If NUMBER is nil, a decimal number is read from the buffer starting
 284 at point, and point moves to the end of that number.
 285 Interactively, NUMBER is the prefix arg (none means nil).
 286
 287 Interactively, reads the register using `register-read-with-preview'."
 288   (interactive (list current-prefix-arg
 289                      (register-read-with-preview "Number to register: ")))
 290   (set-register register
 291                 (if number
 292                     (prefix-numeric-value number)
 293                   (if (looking-at "\\s-*-?[0-9]+")
 294                       (progn
 295                         (goto-char (match-end 0))
 296                         (string-to-number (match-string 0)))
 297                     0))))
 298
 299 (defun increment-register (prefix register)
 300   "Augment contents of REGISTER.
 301 Interactively, PREFIX is in raw form.
 302
 303 If REGISTER contains a number, add `prefix-numeric-value' of
 304 PREFIX to it.
 305
 306 If REGISTER is empty or if it contains text, call
 307 `append-to-register' with `delete-flag' set to PREFIX.
 308
 309 Interactively, reads the register using `register-read-with-preview'."
 310   (interactive (list current-prefix-arg
 311                      (register-read-with-preview "Increment register: ")))
 312   (let ((register-val (get-register register)))
 313     (cond
 314      ((numberp register-val)
 315       (let ((number (prefix-numeric-value prefix)))
 316         (set-register register (+ number register-val))))
 317      ((or (not register-val) (stringp register-val))
 318       (append-to-register register (region-beginning) (region-end) prefix))
 319      (t (error "Register does not contain a number or text")))))
 320
 321 (defun view-register (register)
 322   "Display what is contained in register named REGISTER.
 323 The Lisp value REGISTER is a character.
 324
 325 Interactively, reads the register using `register-read-with-preview'."
 326   (interactive (list (register-read-with-preview "View register: ")))
 327   (let ((val (get-register register)))
 328     (if (null val)
 329         (message "Register %s is empty" (single-key-description register))
 330       (with-output-to-temp-buffer "*Output*"
 331         (describe-register-1 register t)))))
 332
 333 (defun list-registers ()
 334   "Display a list of nonempty registers saying briefly what they contain."
 335   (interactive)
 336   (let ((list (copy-sequence register-alist)))
 337     (setq list (sort list (lambda (a b) (< (car a) (car b)))))
 338     (with-output-to-temp-buffer "*Output*"
 339       (dolist (elt list)
 340         (when (get-register (car elt))
 341           (describe-register-1 (car elt))
 342           (terpri))))))
 343
 344 (defun describe-register-1 (register &optional verbose)
 345   (princ "Register ")
 346   (princ (single-key-description register))
 347   (princ " contains ")
 348   (let ((val (get-register register)))
 349     (cond
 350      ((registerv-p val)
 351       (if (registerv-print-func val)
 352           (funcall (registerv-print-func val) (registerv-data val))
 353         (princ "[UNPRINTABLE CONTENTS].")))
 354
 355      ((numberp val)
 356       (princ val))
 357
 358      ((markerp val)
 359       (let ((buf (marker-buffer val)))
 360         (if (null buf)
 361             (princ "a marker in no buffer")
 362           (princ "a buffer position:\n    buffer ")
 363           (princ (buffer-name buf))
 364           (princ ", position ")
 365           (princ (marker-position val)))))
 366
 367      ((and (consp val) (window-configuration-p (car val)))
 368       (princ "a window configuration."))
 369
 370      ((and (consp val) (frame-configuration-p (car val)))
 371       (princ "a frame configuration."))
 372
 373      ((and (consp val) (eq (car val) 'file))
 374       (princ "the file ")
 375       (prin1 (cdr val))
 376       (princ "."))
 377
 378      ((and (consp val) (eq (car val) 'file-query))
 379       (princ "a file-query reference:\n    file ")
 380       (prin1 (car (cdr val)))
 381       (princ ",\n    position ")
 382       (princ (car (cdr (cdr val))))
 383       (princ "."))
 384
 385      ((consp val)
 386       (if verbose
 387           (progn
 388             (princ "the rectangle:\n")
 389             (while val
 390               (princ "    ")
 391               (princ (car val))
 392               (terpri)
 393               (setq val (cdr val))))
 394         (princ "a rectangle starting with ")
 395         (princ (car val))))
 396
 397      ((stringp val)
 398       (setq val (copy-sequence val))
 399       (if (eq yank-excluded-properties t)
 400           (set-text-properties 0 (length val) nil val)
 401         (remove-list-of-text-properties 0 (length val)
 402                                         yank-excluded-properties val))
 403       (if verbose
 404           (progn
 405             (princ "the text:\n")
 406             (princ val))
 407         (cond
 408          ;; Extract first N characters starting with first non-whitespace.
 409          ((string-match (format "[^ \t\n].\\{,%d\\}"
 410                                 ;; Deduct 6 for the spaces inserted below.
 411                                 (min 20 (max 0 (- (window-width) 6))))
 412                         val)
 413           (princ "text starting with\n    ")
 414           (princ (match-string 0 val)))
 415          ((string-match "^[ \t\n]+$" val)
 416           (princ "whitespace"))
 417          (t
 418           (princ "the empty string")))))
 419      (t
 420       (princ "Garbage:\n")
 421       (if verbose (prin1 val))))))
 422
 423 (defun insert-register (register &optional arg)
 424   "Insert contents of register REGISTER.  (REGISTER is a character.)
 425 Normally puts point before and mark after the inserted text.
 426 If optional second arg is non-nil, puts mark before and point after.
 427 Interactively, second arg is non-nil if prefix arg is supplied.
 428
 429 Interactively, reads the register using `register-read-with-preview'."
 430   (interactive (progn
 431                  (barf-if-buffer-read-only)
 432                  (list (register-read-with-preview "Insert register: ")
 433                        current-prefix-arg)))
 434   (push-mark)
 435   (let ((val (get-register register)))
 436     (cond
 437      ((registerv-p val)
 438       (cl-assert (registerv-insert-func val) nil
 439               "Don't know how to insert register %s"
 440               (single-key-description register))
 441       (funcall (registerv-insert-func val) (registerv-data val)))
 442      ((consp val)
 443       (insert-rectangle val))
 444      ((stringp val)
 445       (insert-for-yank val))
 446      ((numberp val)
 447       (princ val (current-buffer)))
 448      ((and (markerp val) (marker-position val))
 449       (princ (marker-position val) (current-buffer)))
 450      (t
 451       (error "Register does not contain text"))))
 452   (if (not arg) (exchange-point-and-mark)))
 453
 454 (defun copy-to-register (register start end &optional delete-flag region)
 455   "Copy region into register REGISTER.
 456 With prefix arg, delete as well.
 457 Called from program, takes four args: REGISTER, START, END and DELETE-FLAG.
 458 START and END are buffer positions indicating what to copy.
 459 The optional argument REGION if non-nil, indicates that we're not just copying
 460 some text between START and END, but we're copying the region.
 461
 462 Interactively, reads the register using `register-read-with-preview'."
 463   (interactive (list (register-read-with-preview "Copy to register: ")
 464                      (region-beginning)
 465                      (region-end)
 466                      current-prefix-arg
 467                      t))
 468   (set-register register (if region
 469                              (funcall region-extract-function delete-flag)
 470                            (prog1 (filter-buffer-substring start end)
 471                              (if delete-flag (delete-region start end)))))
 472   (setq deactivate-mark t)
 473   (cond (delete-flag)
 474         ((called-interactively-p 'interactive)
 475          (indicate-copied-region))))
 476
 477 (defun append-to-register (register start end &optional delete-flag)
 478   "Append region to text in register REGISTER.
 479 With prefix arg, delete as well.
 480 Called from program, takes four args: REGISTER, START, END and DELETE-FLAG.
 481 START and END are buffer positions indicating what to append.
 482
 483 Interactively, reads the register using `register-read-with-preview'."
 484   (interactive (list (register-read-with-preview "Append to register: ")
 485                      (region-beginning)
 486                      (region-end)
 487                      current-prefix-arg))
 488   (let ((reg (get-register register))
 489         (text (filter-buffer-substring start end))
 490         (separator (and register-separator (get-register register-separator))))
 491     (set-register
 492      register (cond ((not reg) text)
 493                     ((stringp reg) (concat reg separator text))
 494                     (t (error "Register does not contain text")))))
 495   (setq deactivate-mark t)
 496   (cond (delete-flag
 497          (delete-region start end))
 498         ((called-interactively-p 'interactive)
 499          (indicate-copied-region))))
 500
 501 (defun prepend-to-register (register start end &optional delete-flag)
 502   "Prepend region to text in register REGISTER.
 503 With prefix arg, delete as well.
 504 Called from program, takes four args: REGISTER, START, END and DELETE-FLAG.
 505 START and END are buffer positions indicating what to prepend.
 506
 507 Interactively, reads the register using `register-read-with-preview'."
 508   (interactive (list (register-read-with-preview "Prepend to register: ")
 509                      (region-beginning)
 510                      (region-end)
 511                      current-prefix-arg))
 512   (let ((reg (get-register register))
 513         (text (filter-buffer-substring start end))
 514         (separator (and register-separator (get-register register-separator))))
 515     (set-register
 516      register (cond ((not reg) text)
 517                     ((stringp reg) (concat text separator reg))
 518                     (t (error "Register does not contain text")))))
 519   (setq deactivate-mark t)
 520   (cond (delete-flag
 521          (delete-region start end))
 522         ((called-interactively-p 'interactive)
 523          (indicate-copied-region))))
 524
 525 (defun copy-rectangle-to-register (register start end &optional delete-flag)
 526   "Copy rectangular region into register REGISTER.
 527 With prefix arg, delete as well.
 528 To insert this register in the buffer, use \\[insert-register].
 529
 530 Called from a program, takes four args: REGISTER, START, END and DELETE-FLAG.
 531 START and END are buffer positions giving two corners of rectangle.
 532
 533 Interactively, reads the register using `register-read-with-preview'."
 534   (interactive (list (register-read-with-preview
 535                       "Copy rectangle to register: ")
 536                      (region-beginning)
 537                      (region-end)
 538                      current-prefix-arg))
 539   (let ((rectangle (if delete-flag
 540                        (delete-extract-rectangle start end)
 541                      (extract-rectangle start end))))
 542     (set-register register rectangle)
 543     (when (and (null delete-flag)
 544                (called-interactively-p 'interactive))
 545       (setq deactivate-mark t)
 546       (indicate-copied-region (length (car rectangle))))))
 547
 548 (provide 'register)
 549 ;;; register.el ends here