;;; register.el --- register commands for Emacs.

;; Copyright (C) 1985, 1993 Free Software Foundation, Inc.

;; Maintainer: FSF
;; Keywords: internal

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.


;;; Commentary:

;; This package of functions emulates and somewhat extends the venerable
;; TECO's `register' feature, which permits you to save various useful
;; pieces of buffer state to named variables.  The entry points are
;; documented in the Emacs user's manual.

;;; Code:

(defvar register-alist nil
  "Alist of elements (NAME . CONTENTS), one for each Emacs register.
NAME is a character (a number).  CONTENTS is a string, number,
screen configuration, mark or list.
A list of strings represents a rectangle.
A list of the form (file . NAME) represents the file named NAME.")

(defun get-register (char)
  "Return contents of Emacs register named CHAR, or nil if none."
  (cdr (assq char register-alist)))

(defun set-register (char value)
  "Set contents of Emacs register named CHAR to VALUE.  Returns VALUE.
See the documentation of the variable `register-alist' for possible VALUEs."
  (let ((aelt (assq char register-alist)))
    (if aelt
	(setcdr aelt value)
      (setq aelt (cons char value))
      (setq register-alist (cons aelt register-alist)))
    value))

(defun point-to-register (char)
  "Store current location of point in register REGISTER.
Argument is a character, naming the register."
  (interactive "cPoint to register: ")
  (set-register char (point-marker)))
;(defun point-to-register (char &optional arg)
;  "Store current location of point in register REGISTER.
;With prefix argument, store current frame configuration.
;Use \\[jump-to-register] to go to that location or restore that configuration.
;
;Argument is a character, naming the register."
;  (interactive "cPoint to register: \nP")
;  (set-register char (if arg (current-frame-configuration) (point-marker))))

(defun window-configuration-to-register (char)
  "Store the window configuration of the selected frame in register REGISTER.
Use \\[jump-to-register] to restore the configuration.
Argument is a character, naming the register."
  (interactive "cWindow configuration to register: ")
  (set-register char (current-window-configuration)))

;(defun frame-configuration-to-register (char)
;  "Store the window configuration of all frames in register REGISTER.
;Use \\[jump-to-register] to restore the configuration.
;Argument is a character, naming the register."
;  (interactive "cFrame configuration to register: ")
;  (set-register char (current-frame-configuration)))


(define-function 'register-to-point 'jump-to-register)
(defun jump-to-register (char)
  "Move point to location stored in a register.
If the register contains a file name, find that file.
 \(To put a file name in a register, you must use `set-register'.)
If the register contains a window configuration (one screen) or a screen
configuration (all screens), restore that screen or all screens accordingly.
Argument is a character, naming the register."
;Optional second arg non-nil (interactively, prefix argument) says to
;delete any existing frames that the frame configuration doesn't mention.
;\(Otherwise, these frames are iconified.\)
  (interactive "cJump to register: ")
  (let ((val (get-register char)))
    (cond
;;   ((and (fboundp 'frame-configuration-p)
;;         (frame-configuration-p val))
;;    (set-frame-configuration val (not delete)))
     ((window-configuration-p val)
      (set-window-configuration val))
     ((markerp val)
      (switch-to-buffer (marker-buffer val))
      (goto-char val))
     ((and (consp val) (eq (car val) 'file))
      (find-file (cdr val)))
     (t
      (error (gettext "Register doesn't contain a buffer position or configuration"))))))

;(defun number-to-register (arg char)
;  "Store a number in a register.
;Two args, NUMBER and REGISTER (a character, naming the register).
;If NUMBER is nil, digits in the buffer following point are read
;to get the number to store.
;Interactively, NUMBER is the prefix arg (none means nil)."
;  (interactive "P\ncNumber to register: ")
;  (set-register char 
;		(if arg
;		    (prefix-numeric-value arg)
;		  (if (looking-at "[0-9][0-9]*")
;		      (save-excursion
;		       (save-restriction
;			(narrow-to-region (point)
;					  (progn (skip-chars-forward "0-9")
;						 (point)))
;			(goto-char (point-min))
;			(read (current-buffer))))
;		    0))))

;(defun increment-register (arg char)
;  "Add NUMBER to the contents of register REGISTER.
;Interactively, NUMBER is the prefix arg (none means nil)." 
;  (interactive "p\ncNumber to register: ")
;  (or (integerp (get-register char))
;      (error "Register does not contain a number"))
;  (set-register char (+ arg (get-register char))))

(defun view-register (char)
  "Display what is contained in register named REGISTER.
REGISTER is a character."
  (interactive "cView register: ")
  (let ((val (get-register char)))
    (if (null val)
	(message (gettext "Register %s is empty")
		 (single-key-description char))
      (with-output-to-temp-buffer (gettext "*Output*")
	(princ (format (gettext "Register %s contains ")
		       (single-key-description char)))
	(cond 
          ((integerp val)
           (princ val))

          ((markerp val)
           (let ((buf (marker-buffer val)))
             (if (null buf)
                 (princ "a marker in no buffer")
                 (princ (format
                          (gettext "a buffer position:\nbuff %s, position %s")
                          (buffer-name (marker-buffer val))
                          (marker-position val))))))

	 ((window-configuration-p val)
	  (princ (gettext "a window configuration.")))


;;       ((frame-configuration-p val)
;;        (princ "a frame configuration."))

	 ((and (consp val) (eq (car val) 'file))
	  (princ (gettext "the file "))
	  (prin1 (cdr val))
	  (princ "."))

         ((consp val)
          (princ (gettext "the rectangle:\n"))
          (while val
            (princ (car val))
            (terpri)
            (setq val (cdr val))))

	 ((stringp val)
	  (princ (gettext "the text:\n"))
	  (princ val))

         (t
	  (princ (gettext "Garbage:\n"))
	  (prin1 val)))))))

(defun insert-register (char &optional arg)
  "Insert contents of register REG.  REG is a character.
Normally puts point before and mark after the inserted text.
If optional second arg is non-nil, puts mark before and point after.
Interactively, second arg is non-nil if prefix arg is supplied."
  (interactive "cInsert register: \nP")
  (push-mark)
  (let ((val (get-register char)))
    (cond ((consp val)
           (insert-rectangle val))
          ((stringp val)
           (insert val))
          ((integerp val)
           (princ val (current-buffer)))
          ((and (markerp val) (marker-position val))
           (princ (marker-position val) (current-buffer)))
          (t
           (error (gettext "Register does not contain text")))))
  (if (not arg) (exchange-point-and-mark)))

(defun copy-to-register (char start end &optional delete-flag)
  "Copy region into register REG.
With prefix arg, delete as well.
Called from program, takes four args:
REG, START, END and DELETE-FLAG.
START and END are buffer positions indicating what to copy."
  (interactive "cCopy to register: \nr\nP")
  (set-register char (buffer-substring start end))
  (if delete-flag (delete-region start end)))

(defun append-to-register (char start end &optional delete-flag)
  "Append region to text in register REG.
With prefix arg, delete as well.
Called from program, takes four args:
REG, START, END and DELETE-FLAG.
START and END are buffer positions indicating what to append."
  (interactive "cAppend to register: \nr\nP")
  (or (stringp (get-register char))
      (error (gettext "Register does not contain text")))
  (set-register char (concat (get-register char)
			     (buffer-substring start end)))
  (if delete-flag (delete-region start end)))

(defun prepend-to-register (char start end &optional delete-flag)
  "Prepend region to text in register REG.
With prefix arg, delete as well.
Called from program, takes four args:
REG, START, END and DELETE-FLAG.
START and END are buffer positions indicating what to prepend."
  (interactive "cPrepend to register: \nr\nP")
  (or (stringp (get-register char))
      (error (gettext "Register does not contain text")))
  (set-register char (concat (buffer-substring start end)
			     (get-register char)))
  (if delete-flag (delete-region start end)))

(defun copy-rectangle-to-register (char start end &optional delete-flag)
  "Copy rectangular region into register REG.
With prefix arg, delete as well.
Called from program, takes four args:
REG, START, END and DELETE-FLAG.
START and END are buffer positions giving two corners of rectangle."
  (interactive "cCopy rectangle to register: \nr\nP")
  (set-register char
		(if delete-flag
		    (delete-extract-rectangle start end)
		  (extract-rectangle start end))))

;;; register.el ends here