path: root/lisp/emulation/edt.el

;;; edt.el --- enhanced EDT keypad mode emulation for GNU Emacs

;; Copyright (C) 1986, 1992-1995, 2000-2021 Free Software Foundation,
;; Inc.

;; Author: Kevin Gallagher <kevin.gal@verizon.net>
;; Keywords: emulations

;; 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 3 of the License, 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.  If not, see <https://www.gnu.org/licenses/>.



;;; Commentary:
;;

;; This is Version 4.0 of the EDT Emulation for Emacs.
;; It comes with special functions which replicate nearly all of EDT's
;; keypad mode behavior.  It sets up default keypad and function key
;; bindings which closely match those found in EDT.  Support is
;; provided so that users may reconfigure most keypad and function key
;; bindings to their own liking.

;; NOTE: Version 4.0 contains several enhancements.  See the
;; Enhancement section below for the details.

;; Getting Started:

;; To start the EDT Emulation, first start Emacs and then enter
;;
;;    M-x edt-emulation-on
;;
;; to begin the emulation.  After initialization is complete, the
;; following message will appear below the status line informing you
;; that the emulation has been enabled: "Default EDT keymap active".

;; You can have the EDT Emulation start up automatically, each time
;; you initiate a GNU Emacs session, by adding the following line to
;; your init file:
;;
;;    (add-hook 'emacs-startup-hook 'edt-emulation-on)

;; IMPORTANT: Be sure to read the Info node `edt' for more details.
;; It contains very helpful user information.

;; The EDT emulation consists of the following files:
;;
;; edt.texi         - User manual
;; edt-user.el      - Sample Customization File (located in Emacs
;;                      distribution etc directory)
;; edt.el           - EDT Emulation Functions and Default Configuration
;; edt-lk201.el     - Built-in support for DEC LK-201 Keyboards
;; edt-vt100.el     - Built-in support for DEC VT-100 (and above) terminals
;; edt-pc.el        - Built-in support for PC 101 Keyboards under MS-DOS
;; edt-mapper.el    - Create an EDT LK-201 Map File for Keyboards Without
;;                      Built-in Support

;; Enhancements:

;; Version 4.0 contains the following enhancements:

;;  1.  Scroll margins at the top and bottom of the window are now
;;      supported.  (The design was copied from tpu-extras.el.)  By
;;      default, this feature is enabled, with the top margin set to
;;      10% of the window and the bottom margin set to 15% of the
;;      window.  To change these settings, you can invoke the function
;;      edt-set-scroll-margins in your init file.  For example, the
;;      following line
;;
;;           (edt-set-scroll-margins "20%" "25%")
;;
;;      sets the top margin to 20% of the window and the bottom margin
;;      to 25% of the window.  To disable this feature, set each
;;      margin to 0%.  You can also invoke edt-set-scroll-margins
;;      interactively while EDT Emulation is active to change the
;;      settings for that session.
;;
;;      NOTE: Another way to set the scroll margins is to use the
;;      Emacs customization feature to set the following two variables
;;      directly:
;;
;;           edt-top-scroll-margin and edt-bottom-scroll-margin
;;
;;      Enter the Emacs `customize' command.  First select the Editing
;;      group and then select the Emulations group.  Finally, select
;;      the Edt group and follow the directions.
;;
;;  2.  The SUBS command is now supported and bound to GOLD-Enter by
;;      default.  (This design was copied from tpu-edt.el.)  Note, in
;;      earlier versions of EDT Emulation, GOLD-Enter was assigned to
;;      the Emacs function `query-replace'.  The binding of
;;      `query-replace' has been moved to GOLD-/.  If you prefer to
;;      restore `query-replace' to GOLD-Enter, then use an EDT user
;;      customization file, edt-user.el, to do this.
;;      See Info node `edt' for more details.

;;  3.  If you access a workstation using an X Server, observe that
;;      the initialization file generated by edt-mapper.el will now
;;      contain the name of the X Server vendor.  This is a
;;      convenience for those who have access to their Unix account
;;      from more than one type of X Server.  Since different X
;;      Servers typically require different EDT emulation
;;      initialization files, edt-mapper.el will now generate these
;;      different initialization files and save them with different
;;      names.  Then, the correct initialization file for the
;;      particular X server in use is loaded correctly automatically.

;;  4.  Also, edt-mapper.el is now capable of binding an ASCII key
;;      sequence, providing the ASCII key sequence prefix is already
;;      known by Emacs to be a prefix.  As a result of providing this
;;      support, some terminal/keyboard/window system configurations,
;;      which don't have a complete set of sensible function key
;;      bindings built into Emacs in `function-key-map', can still be
;;      configured for use with EDT Emulation.  (Note: In a few rare
;;      circumstances this does not work properly.  In particular, it
;;      does not work if a subset of the leading ASCII characters in a
;;      key sequence are recognized by Emacs as having an existing
;;      binding.  For example, if the keypad 7 (KP-7) key generates
;;      the sequence \"<ESC>Ow\" and \"<ESC>O\" is already bound to a
;;      function, pressing KP-7 when told to do so by edt-mapper.el
;;      will result in edt-mapper.el incorrectly mapping \"<ESC>O\" to
;;      KP-7 and \"w\" to KP-8.  If something like this happens to
;;      you, it is probably a bug in the support for your keyboard
;;      within Emacs OR a bug in the Unix termcap/terminfo support for
;;      your terminal OR a bug in the terminal emulation software you
;;      are using.)

;;  5.  The edt-quit function (bound to GOLD-q by default) has been
;;      modified to warn the user when file-related buffer
;;      modifications exist.  It now cautions the user that those
;;      modifications will be lost if the user quits without saving
;;      those buffers.


;;; History:
;;
;;  Version 4.0    2000    Added New Features and Fixed a Few Bugs
;;


;;; Code:

;;;  Electric Help functions are used for keypad help displays.  A few
;;;  picture functions are used in rectangular cut and paste commands.

(require 'ehelp)
(require 'picture)

;;;;
;;;; VARIABLES and CONSTANTS
;;;;

(defgroup edt nil
  "Emacs emulating EDT."
  :prefix "edt-"
  :group 'emulations)

;; To silence the byte-compiler
(defvar *EDT-keys*)
(defvar edt-default-global-map)
(defvar edt-last-copied-word)
(defvar edt-learn-macro-count)
(defvar edt-orig-page-delimiter)
(defvar edt-orig-transient-mark-mode)
(defvar edt-rect-start-point)
(defvar edt-user-global-map)
(defvar rect-start-point)

(defconst edt-version "4.0" "EDT Emulation version number.")
(make-obsolete-variable 'edt-version nil "28.1")

;;;
;;;  User Configurable Variables
;;;

(defcustom edt-keep-current-page-delimiter nil
  "Emacs MUST be restarted for a change in value to take effect!
Non-nil leaves Emacs value of `page-delimiter' unchanged within EDT
Emulation.  If set to nil (the default), the `page-delimiter' variable
is set to \"\\f\" when edt-emulation-on is first invoked.  This
setting replicates EDT's page delimiter behavior.  The original value
is restored when edt-emulation-off is called."
  :type 'boolean
  :group 'edt)

(defcustom edt-use-EDT-control-key-bindings nil
  "Emacs MUST be restarted for a change in value to take effect!
Non-nil causes the control key bindings to be replaced with EDT
bindings.  If set to nil (the default), EDT control key bindings are
not used and the current Emacs control key bindings are retained for
use within the EDT emulation."
  :type 'boolean
  :group 'edt)

(defcustom edt-word-entities '(?\t)
  "Specifies the list of EDT word entity characters.
The default list, (?\\t), contains just the TAB character, which
emulates EDT.  Characters are specified in the list using their
decimal ASCII values.  A question mark, followed by the actual
character, can be used to indicate the numerical value of the
character, instead of the actual decimal value.  So, ?A means the
numerical value for the letter A, ?/ means the numerical value for /,
etc.  Several unprintable and special characters have special
representations, which you can also use:

            ?\\b  specifies  BS, C-h
            ?\\t  specifies  TAB, C-i
            ?\\n  specifies  LFD, C-j
            ?\\v  specifies  VTAB, C-k
            ?\\f  specifies  FF, C-l
            ?\\r  specifies  CR, C-m
            ?\\e  specifies  ESC, C-[
            ?\\\\  specifies  \\

In EDT Emulation movement-by-word commands, each character in the list
will be treated as if it were a separate word."
  :type '(repeat integer)
  :group 'edt)

(defcustom edt-top-scroll-margin 10
  "Scroll margin at the top of the screen.
Interpreted as a percent of the current window size with a default
setting of 10%.  If set to 0, top scroll margin is disabled."
  :type 'integer
  :group 'edt)

(defcustom edt-bottom-scroll-margin 15
  "Scroll margin at the bottom of the screen.
Interpreted as a percent of the current window size with a default
setting of 15%.  If set to 0, bottom scroll margin is disabled."
  :type 'integer
  :group 'edt)

;;;
;;; Internal Variables
;;;

(defvar edt-last-deleted-lines ""
  "Last text deleted by the EDT emulation DEL L command.")

(defvar edt-last-deleted-words ""
  "Last text deleted by the EDT emulation DEL W command.")

(defvar edt-last-deleted-chars ""
  "Last text deleted by the EDT emulation DEL C command.")

(defvar edt-find-last-text ""
  "Last text found by the EDT emulation FIND command.")

(defvar edt-match-beginning-mark (make-marker)
  "Used internally by the EDT emulation SUBS command.")

(defvar edt-match-end-mark (make-marker)
  "Used internally by the EDT emulation SUBS command.")

(defvar edt-last-replaced-key-definition nil
  "Key definition replaced with `edt-define-key' or `edt-learn' command.")

(defvar edt-direction-string ""
  "String indicating current direction of movement.")

(defvar edt-select-mode nil
  "Non-nil means select mode is active.")

(defvar edt-select-mode-current ""
  "Text displayed in mode line to indicate the state of EDT select mode.
When select mode is inactive, it is set to an empty string.")

(defconst edt-select-mode-string " Select"
  "Used in mode line to indicate select mode is active.")

(defconst edt-forward-string " ADVANCE"
  "Direction string in mode line to indicate forward movement.")

(defconst edt-backward-string "  BACKUP"
  "Direction string in mode line to indicate backward movement.")

(defvar edt-default-map-active nil
  "Non-nil indicates that default EDT emulation key bindings are active.
nil means user-defined custom bindings are active.")

(defvar edt-user-map-configured nil
  "Non-nil indicates that user custom EDT key bindings are configured.
This means that an edt-user.el file was found in the user's `load-path'.")

(defvar edt-term nil
  "Specifies the terminal type, if applicable.")

;;;
;;;  Emacs version identifiers - currently referenced by
;;;
;;;     o edt-emulation-on      o edt-load-keys
;;;
(defconst edt-xserver (when (eq window-system 'x)
			;; The Cygwin window manager has a `/' in its
			;; name, which breaks the generated file name of
			;; the custom key map file.  Replace `/' with a
			;; `-' to work around that.
                        (replace-regexp-in-string "[ /]" "-"
                                                  (x-server-vendor)))
  "Indicates X server vendor name, if applicable.")

(defvar edt-keys-file nil
  "User's custom keypad and function keys mappings to emulate LK-201 keyboard.")

(defvar edt-last-copied-word nil
  "Last word that the user copied.")


;;;;
;;;; EDT Emulation Commands
;;;;

;;; Almost all of EDT's keypad mode commands have equivalent Emacs
;;; function counterparts.  But many of these counterparts behave
;;; somewhat differently in Emacs.
;;;
;;; So, the following Emacs functions emulate, where practical, the
;;; exact behavior of the corresponding EDT keypad mode commands.  In
;;; a few cases, the emulation is not exact, but it should be close
;;; enough for most EDT die-hards.
;;;

;;;
;;; PAGE
;;;
;;; Emacs uses the regexp assigned to page-delimiter to determine what
;;; marks a page break.  This is normally "^\f", which causes the
;;; edt-page command to ignore form feeds not located at the beginning
;;; of a line.  To emulate the EDT PAGE command exactly,
;;; page-delimiter is set to "\f" when EDT emulation is turned on, and
;;; restored to its original value when EDT emulation is turned off.
;;; But this can be overridden if the EDT definition is not desired by
;;; placing
;;;
;;;         (setq edt-keep-current-page-delimiter t)
;;;
;;; in your init file.

(defun edt-page-forward (num)
  "Move forward to just after next page delimiter.
Argument NUM is the number of page delimiters to move."
  (interactive "p")
  (edt-check-prefix num)
  (if (eobp)
      (error "End of buffer")
	(progn
	  (forward-page num)
	  (if (eobp)
		  (edt-line-to-bottom-of-window)
		(edt-line-to-top-of-window)))))

(defun edt-page-backward (num)
  "Move backward to just after previous page delimiter.
Argument NUM is the number of page delimiters to move."
  (interactive "p")
  (edt-check-prefix num)
  (if (bobp)
      (error "Beginning of buffer")
	(progn
	  (backward-page num)
      (edt-line-to-top-of-window))))

(defun edt-page (num)
  "Move in current direction to next page delimiter.
Argument NUM is the number of page delimiters to move."
  (interactive "p")
  (if (equal edt-direction-string edt-forward-string)
      (edt-page-forward num)
    (edt-page-backward num)))

;;;
;;; SECT
;;;
;;; EDT defaults a section size to be 16 lines of its one and only
;;; 24-line window.  That's two-thirds of the window at a time.  The
;;; EDT SECT commands moves the cursor, not the window.
;;;
;;; This emulation of EDT's SECT moves the cursor approximately
;;; two-thirds of the current window at a time.

(defun edt-sect-forward (num)
  "Move cursor forward two-thirds of a window's number of lines.
Argument NUM is the number of sections to move."
  (interactive "p")
  (edt-check-prefix num)
  (edt-line-forward (* (* (/ (- (window-height) 1) 3) 2) num)))


(defun edt-sect-backward (num)
  "Move cursor backward two-thirds of a window.
Argument NUM is the number of sections to move."
  (interactive "p")
  (edt-check-prefix num)
  (edt-line-backward (* (* (/ (- (window-height) 1) 3) 2) num)))

(defun edt-sect (num)
  "Move in current direction a full window.
Argument NUM is the number of sections to move."
  (interactive "p")
  (if (equal edt-direction-string edt-forward-string)
      (edt-sect-forward num)
    (edt-sect-backward num)))

;;;
;;; BEGINNING OF LINE
;;;
;;; EDT's beginning-of-line command is not affected by current
;;; direction, for some unknown reason.

(defun edt-beginning-of-line (num)
  "Move backward to next beginning of line mark.
Argument NUM is the number of BOL marks to move."
  (interactive "p")
  (edt-check-prefix num)
  (let ((beg (edt-current-line)))
    (if (bolp)
	(forward-line (* -1 num))
      (progn
	(setq num (1- num))
	(forward-line (* -1 num))))
    (edt-top-check beg num)))


;;;
;;; EOL (End of Line)
;;;

(defun edt-end-of-line-forward (num)
  "Move forward to next end of line mark.
Argument NUM is the number of EOL marks to move."
  (interactive "p")
  (edt-check-prefix num)
  (let ((beg (edt-current-line)))
    (forward-char)
    (end-of-line num)
    (edt-bottom-check beg num)))


(defun edt-end-of-line-backward (num)
  "Move backward to next end of line mark.
Argument NUM is the number of EOL marks to move."
  (interactive "p")
  (edt-check-prefix num)
  (let ((beg (edt-current-line)))
    (end-of-line (1- num))
    (edt-top-check beg num)))


(defun edt-end-of-line (num)
  "Move in current direction to next end of line mark.
Argument NUM is the number of EOL marks to move."
  (interactive "p")
  (if (equal edt-direction-string edt-forward-string)
      (edt-end-of-line-forward num)
    (edt-end-of-line-backward num)))

;;;
;;; WORD
;;;
;;; This one is a tad messy.  To emulate EDT's behavior everywhere in
;;; the file (beginning of file, end of file, beginning of line, end
;;; of line, etc.) it takes a bit of special handling.
;;;
;;; The variable edt-word-entities contains a list of characters which
;;; are to be viewed as distinct words wherever they appear in the
;;; buffer.  This emulates the EDT line mode command SET ENTITY WORD.


(defun edt-one-word-forward ()
  "Move forward to first character of next word."
  (interactive)
  (if (eobp)
      (error "End of buffer"))
  (if (eolp)
      (forward-char)
    (progn
      (if (memq (following-char) edt-word-entities)
	  (forward-char)
	(while (and
		(not (eolp))
		(not (eobp))
		(not (eq ?\  (char-syntax (following-char))))
		(not (memq (following-char) edt-word-entities)))
	  (forward-char)))
      (while (and
	      (not (eolp))
	      (not (eobp))
	      (eq ?\  (char-syntax (following-char)))
	      (not (memq (following-char) edt-word-entities)))
	(forward-char)))))

(defun edt-one-word-backward ()
  "Move backward to first character of previous word."
  (interactive)
  (if (bobp)
      (error "Beginning of buffer"))
  (if (bolp)
      (backward-char)
    (progn
      (backward-char)
      (while (and
	      (not (bolp))
	      (not (bobp))
	      (eq ?\  (char-syntax (following-char)))
	      (not (memq (following-char) edt-word-entities)))
	(backward-char))
      (if (not (memq (following-char) edt-word-entities))
	  (while (and
		  (not (bolp))
		  (not (bobp))
		  (not (eq ?\  (char-syntax (preceding-char))))
		  (not (memq (preceding-char) edt-word-entities)))
	    (backward-char))))))

(defun edt-word-forward (num)
  "Move forward to first character of next word.
Argument NUM is the number of words to move."
  (interactive "p")
  (edt-check-prefix num)
  (while (> num 0)
    (edt-one-word-forward)
    (setq num (1- num))))

(defun edt-word-backward (num)
  "Move backward to first character of previous word.
Argument NUM is the number of words to move."
  (interactive "p")
  (edt-check-prefix num)
  (while (> num 0)
    (edt-one-word-backward)
    (setq num (1- num))))

(defun edt-word (num)
  "Move in current direction to first character of next word.
Argument NUM is the number of words to move."
  (interactive "p")
  (if (equal edt-direction-string edt-forward-string)
      (edt-word-forward num)
    (edt-word-backward num)))

;;;
;;; CHAR
;;;

(defun edt-character (num)
  "Move in current direction to next character.
Argument NUM is the number of characters to move."
  (interactive "p")
  (edt-check-prefix num)
  (if (equal edt-direction-string edt-forward-string)
      (forward-char num)
    (backward-char num)))

;;;
;;; LINE
;;;
;;; When direction is set to BACKUP, LINE behaves just like BEGINNING
;;; OF LINE in EDT.  So edt-line-backward is not really needed as a
;;; separate function.

(defun edt-line-backward (num)
  "Move backward to next beginning of line mark.
Argument NUM is the number of BOL marks to move."
  (interactive "p")
  (edt-beginning-of-line num))

(defun edt-line-forward (num)
  "Move forward to next beginning of line mark.
Argument NUM is the number of BOL marks to move."
  (interactive "p")
  (edt-check-prefix num)
  (let ((beg (edt-current-line)))
    (forward-line num)
    (edt-bottom-check beg num)))

(defun edt-line (num)
  "Move in current direction to next beginning of line mark.
Argument NUM is the number of BOL marks to move."
  (interactive "p")
  (if (equal edt-direction-string edt-forward-string)
      (edt-line-forward num)
    (edt-line-backward num)))

;;;
;;; UP and DOWN Arrows
;;;

(defun edt-next-line (num)
  "Move cursor down one line.
Argument NUM is the number of lines to move."
  (interactive "p")
  (edt-check-prefix num)
  (let ((beg (edt-current-line)))
    ;; We're deliberately using next-line instead of forward-line.
    (with-no-warnings (next-line num))
    (edt-bottom-check beg num)))

(defun edt-previous-line (num)
  "Move cursor up one line.
Argument NUM is the number of lines to move."
  (interactive "p")
  (edt-check-prefix num)
  (let ((beg (edt-current-line)))
    ;; We're deliberately using previous-line instead of forward-line.
    (with-no-warnings (previous-line num))
    (edt-top-check beg num)))


;;;
;;; TOP
;;;

(defun edt-top ()
  "Move cursor to the beginning of buffer."
  (interactive)
  (goto-char (point-min)))

;;;
;;; BOTTOM
;;;

(defun edt-bottom ()
  "Move cursor to the end of buffer."
  (interactive)
  (goto-char (point-max))
  (edt-line-to-bottom-of-window))

(defmacro edt-with-position (&rest body)
  "Execute BODY with some position-related variables bound."
  `(let* ((left nil)
          (beg (edt-current-line))
          (height (window-height))
          (top-percent
           (if (zerop edt-top-scroll-margin) 10 edt-top-scroll-margin))
          (bottom-percent
           (if (zerop edt-bottom-scroll-margin) 15 edt-bottom-scroll-margin))
          (top-margin (/ (* height top-percent) 100))
          (bottom-up-margin (1+ (/ (* height bottom-percent) 100)))
          (bottom-margin (max beg (- height bottom-up-margin 1)))
          (top (save-excursion (move-to-window-line top-margin) (point)))
          (bottom (save-excursion (move-to-window-line bottom-margin) (point)))
          (far (save-excursion
                 (goto-char bottom)
                 (point-at-bol (1- height)))))
     ,@body))

;;;
;;; FIND
;;;

(defun edt-find-forward (&optional find)
  "Find first occurrence of a string in forward direction and save it.
Optional argument FIND is t is this function is called from `edt-find'."
  (interactive)
  (or find
      (setq edt-find-last-text (read-string "Search forward: ")))
  (edt-with-position
   (when (search-forward edt-find-last-text) ; FIXME noerror?
     (search-backward edt-find-last-text)
     (edt-set-match)
     (if (> (point) far)
         (if (zerop (setq left (save-excursion (forward-line height))))
             (recenter top-margin)
           (recenter (- left bottom-up-margin)))
       (and (> (point) bottom) (recenter bottom-margin))))))

(defun edt-find-backward (&optional find)
  "Find first occurrence of a string in the backward direction and save it.
Optional argument FIND is t if this function is called from `edt-find'."
  (interactive)
  (or find
      (setq edt-find-last-text (read-string "Search backward: ")))
  (edt-with-position
   (if (search-backward edt-find-last-text)
       (edt-set-match))
   (and (< (point) top) (recenter (min beg top-margin)))))

(defun edt-find ()
  "Find first occurrence of string in current direction and save it."
  (interactive)
  (setq edt-find-last-text (read-string "Search: "))
  (if (equal edt-direction-string edt-forward-string)
      (edt-find-forward t)
      (edt-find-backward t)))


;;;
;;; FNDNXT
;;;

(defun edt-find-next-forward ()
  "Find next occurrence of a string in forward direction."
  (interactive)
  (edt-with-position
   (forward-char 1)
   (if (search-forward edt-find-last-text nil t)
       (progn
         (search-backward edt-find-last-text)
         (edt-set-match)
         (if (> (point) far)
             (if (zerop (setq left (save-excursion (forward-line height))))
                 (recenter top-margin)
               (recenter (- left bottom-up-margin)))
           (and (> (point) bottom) (recenter bottom-margin))))
     (backward-char 1)
     (error "Search failed: \"%s\"" edt-find-last-text))))

(defun edt-find-next-backward ()
  "Find next occurrence of a string in backward direction."
  (interactive)
  (edt-with-position
   (if (not (search-backward edt-find-last-text nil t))
       (error "Search failed: \"%s\"" edt-find-last-text)
     (edt-set-match)
     (and (< (point) top) (recenter (min beg top-margin))))))

(defun edt-find-next ()
  "Find next occurrence of a string in current direction."
  (interactive)
  (if (equal edt-direction-string edt-forward-string)
      (edt-find-next-forward)
    (edt-find-next-backward)))

;;;
;;; APPEND
;;;

(defun edt-append ()
  "Append this kill region to last killed region."
  (interactive "*")
  (edt-check-selection)
  (append-next-kill)
  (kill-region (mark) (point))
  (message "Selected text APPENDED to kill ring"))

;;;
;;; DEL L
;;;

(defun edt-delete-line (num)
  "Delete from cursor up to and including the end of line mark.
Argument NUM is the number of lines to delete."
  (interactive "*p")
  (edt-check-prefix num)
  (let ((beg (point)))
    (forward-line num)
    (if (not (eq (preceding-char) ?\n))
        (insert "\n"))
    (setq edt-last-deleted-lines
          (buffer-substring beg (point)))
    (delete-region beg (point))))

;;;
;;; DEL EOL
;;;

(defun edt-delete-to-end-of-line (num)
  "Delete from cursor up to but excluding the end of line mark.
Argument NUM is the number of lines to delete."
  (interactive "*p")
  (edt-check-prefix num)
  (let ((beg (point)))
    (forward-char 1)
    (end-of-line num)
    (setq edt-last-deleted-lines
          (buffer-substring beg (point)))
    (delete-region beg (point))))

;;;
;;; SELECT
;;;

(defun edt-select-mode (arg)
  "Turn EDT select mode off if ARG is nil; otherwise, turn EDT select mode on.
In select mode, selected text is highlighted."
  (if arg
      (progn
        (setq-local edt-select-mode 'edt-select-mode-current)
	(setq rect-start-point (window-point)))
    (progn
      (kill-local-variable 'edt-select-mode)))
  (force-mode-line-update))

(defun edt-select ()
  "Set mark at cursor and start text selection."
  (interactive)
  (set-mark-command nil))

(defun edt-reset ()
  "Cancel text selection."
  (interactive)
  (deactivate-mark))

;;;
;;; CUT
;;;

(defun edt-cut ()
  "Deletes selected text but copies to kill ring."
  (interactive "*")
  (edt-check-selection)
  (kill-region (mark) (point))
  (message "Selected text CUT to kill ring"))

;;;
;;; DELETE TO BEGINNING OF LINE
;;;

(defun edt-delete-to-beginning-of-line (num)
  "Delete from cursor to beginning of line.
Argument NUM is the number of lines to delete."
  (interactive "*p")
  (edt-check-prefix num)
  (let ((beg (point)))
    (edt-beginning-of-line num)
    (setq edt-last-deleted-lines
          (buffer-substring (point) beg))
    (delete-region beg (point))))

;;;
;;; DEL W
;;;

(defun edt-delete-word (num)
  "Delete from cursor up to but excluding first character of next word.
Argument NUM is the number of words to delete."
  (interactive "*p")
  (edt-check-prefix num)
  (let ((beg (point)))
    (edt-word-forward num)
    (setq edt-last-deleted-words (buffer-substring beg (point)))
    (delete-region beg (point))))

;;;
;;; DELETE TO BEGINNING OF WORD
;;;

(defun edt-delete-to-beginning-of-word (num)
  "Delete from cursor to beginning of word.
Argument NUM is the number of words to delete."
  (interactive "*p")
  (edt-check-prefix num)
  (let ((beg (point)))
    (edt-word-backward num)
    (setq edt-last-deleted-words (buffer-substring (point) beg))
    (delete-region beg (point))))

;;;
;;; DEL C
;;;

(defun edt-delete-character (num)
  "Delete character under cursor.
Argument NUM is the number of characters to delete."
  (interactive "*p")
  (edt-check-prefix num)
  (setq edt-last-deleted-chars
        (buffer-substring (point) (min (point-max) (+ (point) num))))
  (delete-region (point) (min (point-max) (+ (point) num))))

;;;
;;; DELETE CHAR
;;;

(defun edt-delete-previous-character (num)
  "Delete character in front of cursor.
Argument NUM is the number of characters to delete."
  (interactive "*p")
  (edt-check-prefix num)
  (setq edt-last-deleted-chars
        (buffer-substring (max (point-min) (- (point) num)) (point)))
  (delete-region (max (point-min) (- (point) num)) (point)))

;;;
;;; UND L
;;;

(defun edt-undelete-line ()
  "Undelete previous deleted line(s)."
  (interactive "*")
  (point-to-register 1)
  (insert edt-last-deleted-lines)
  (register-to-point 1))

;;;
;;; UND W
;;;

(defun edt-undelete-word ()
  "Undelete previous deleted word(s)."
  (interactive "*")
  (point-to-register 1)
  (insert edt-last-deleted-words)
  (register-to-point 1))

;;;
;;; UND C
;;;

(defun edt-undelete-character ()
  "Undelete previous deleted character(s)."
  (interactive "*")
  (point-to-register 1)
  (insert edt-last-deleted-chars)
  (register-to-point 1))

;;;
;;; REPLACE
;;;

(defun edt-replace ()
  "Replace marked section with last CUT (killed) text."
  (interactive "*")
  (if (edt-check-match)
      (replace-match (car kill-ring-yank-pointer))
    (progn
      (exchange-point-and-mark)
      (let ((beg (point)))
	(exchange-point-and-mark)
	(delete-region beg (point)))
      (yank))))

;;;
;;; SUBS
;;;

(defun edt-substitute (num)
  "Replace the selected region with the contents of the CUT buffer and.
Repeat the most recent FIND command.  (The Emacs kill ring is used as
the CUT buffer.)
Argument NUM is the repeat count.  A positive value indicates the of times
to repeat the substitution.  A negative argument means replace all occurrences
of the search text."
  (interactive "p")
  (cond ((or edt-select-mode (edt-check-match))
	 (while (and (not (= num 0)) (or edt-select-mode (edt-check-match)))
	   (edt-replace)
	   (edt-find-next)
	   (setq num (1- num))))
	(t
	 (error "No selection active"))))

(defun edt-set-match nil
  "Set markers at match beginning and end."
  ;; Add one to beginning mark so it stays with the first character of
  ;;   the string even if characters are added just before the string.
  (setq edt-match-beginning-mark (copy-marker (1+ (match-beginning 0))))
  (setq edt-match-end-mark (copy-marker (match-end 0))))

(defun edt-unset-match nil
  "Unset match beginning and end markers."
  (set-marker edt-match-beginning-mark nil)
  (set-marker edt-match-end-mark nil))

(defun edt-match-beginning nil
  "Return the location of the last match beginning."
  (1- (marker-position edt-match-beginning-mark)))

(defun edt-match-end nil
  "Return the location of the last match end."
  (marker-position edt-match-end-mark))

(defun edt-check-match nil
  "Return t if point is between edt-match markers.
Otherwise sets the edt-match markers to nil and returns nil."
  ;; make sure 1- marker is in this buffer
  ;;           2- point is at or after beginning marker
  ;;           3- point is before ending marker, or in the case of
  ;;              zero length regions (like bol, or eol) that the
  ;;              beginning, end, and point are equal.
  (cond ((and
	  (equal (marker-buffer edt-match-beginning-mark) (current-buffer))
	  (>= (point) (1- (marker-position edt-match-beginning-mark)))
	  (or
	   (< (point) (marker-position edt-match-end-mark))
	   (and (= (1- (marker-position edt-match-beginning-mark))
		   (marker-position edt-match-end-mark))
		(= (marker-position edt-match-end-mark) (point))))) t)
	(t
	 (edt-unset-match) nil)))

(defun edt-show-match-markers nil
  "Show the values of the match markers."
  (interactive)
  (if (markerp edt-match-beginning-mark)
      (let ((beg (marker-position edt-match-beginning-mark)))
	(message "(%s, %s) in %s -- current %s in %s"
		 (if beg (1- beg) nil)
		 (marker-position edt-match-end-mark)
		 (marker-buffer edt-match-end-mark)
		 (point) (current-buffer)))))


;;;
;;; ADVANCE
;;;

(defun edt-advance ()
  "Set movement direction forward.
Also, execute command specified if in Minibuffer."
  (interactive)
  (setq edt-direction-string edt-forward-string)
  (force-mode-line-update)
  (if (string-equal " *Minibuf"
                    (substring (buffer-name) 0 (min (length (buffer-name)) 9)))
      (exit-minibuffer)))


;;;
;;; BACKUP
;;;

(defun edt-backup ()
  "Set movement direction backward.
Also, execute command specified if in Minibuffer."
  (interactive)
  (setq edt-direction-string edt-backward-string)
  (force-mode-line-update)
  (if (string-equal " *Minibuf"
                    (substring (buffer-name) 0 (min (length (buffer-name)) 9)))
      (exit-minibuffer)))


;;;
;;; CHNGCASE
;;;
;; This function is based upon Jeff Kowalski's case-flip function in his
;; tpu.el.

(defun edt-change-case (num)
  "Change the case of specified characters.
If text selection IS active, then characters between the cursor and mark are
changed.  If text selection is NOT active, there are two cases.  First, if the
current direction is ADVANCE, then the prefix number of character(s) under and
following cursor are changed.  Second, if the current direction is BACKUP, then
the prefix number of character(s) before the cursor are changed.  Accepts a
positive prefix for the number of characters to change, but the prefix is
ignored if text selection is active.
Argument NUM is the numbers of consecutive characters to change."
  (interactive "*p")
  (edt-check-prefix num)
  (if edt-select-mode
      (let ((end (max (mark) (point)))
            (point-save (point)))
        (goto-char (min (point) (mark)))
        (while (not (eq (point) end))
          (funcall (if (<= ?a (following-char))
                       'upcase-region 'downcase-region)
                   (point) (1+ (point)))
          (forward-char 1))
        (goto-char point-save))
    (progn
      (if (string= edt-direction-string edt-backward-string)
	  (backward-char num))
      (while (> num 0)
	(funcall (if (<= ?a (following-char))
		     'upcase-region 'downcase-region)
		 (point) (1+ (point)))
	(forward-char 1)
	(setq num (1- num))))))

;;;
;;; DEFINE KEY
;;;

(defun edt-define-key ()
  "Assign an interactively-callable function to a specified key sequence.
The current key definition is saved in `edt-last-replaced-key-definition'.
Use `edt-restore-key' to restore last replaced key definition."
  (interactive)
  (let (edt-function
	edt-key-definition)
    (setq edt-key-definition
	  (read-key-sequence "Press the key to be defined: "))
    (if (string-equal "\C-m" edt-key-definition)
        (message "Key not defined")
      (progn
	(setq edt-function (read-command "Enter command name: "))
	(if (string-equal "" edt-function)
	    (message "Key not defined")
	  (progn
	    (setq edt-last-replaced-key-definition
		  (lookup-key (current-global-map) edt-key-definition))
	    (define-key (current-global-map)
	      edt-key-definition edt-function)))))))

;;;
;;; FORM FEED INSERT
;;;

(defun edt-form-feed-insert (num)
  "Insert form feed character at cursor position.
Argument NUM is the number of form feeds to insert."
  (interactive "*p")
  (edt-check-prefix num)
  (while (> num 0)
    (insert ?\f)
    (setq num (1- num))))

;;;
;;; TAB INSERT
;;;

(defun edt-tab-insert (num)
  "Insert tab character at cursor position.
Argument NUM is the number of tabs to insert."
  (interactive "*p")
  (edt-check-prefix num)
  (while (> num 0)
    (insert ?\t)
    (setq num (1- num))))

;;;
;;; Check Prefix
;;;

(defun edt-check-prefix (num)
  "Indicate error if prefix is not positive.
Argument NUM is the prefix value tested."
  (if (<= num 0)
      (error "Prefix must be positive")))

;;;
;;; Check Selection
;;;

(defun edt-check-selection ()
  "Indicate error if EDT selection is not active."
  (if (not edt-select-mode)
      (error "Selection NOT active")))

;;;
;;; Scroll Margins
;;;

(defun edt-top-check (beg lines)
  "Enforce scroll margin at the top of screen.
Argument BEG is the starting line number before cursor was moved.
Argument LINES is the number of lines the cursor moved toward the top."
  (let ((margin	 (/ (* (window-height) edt-top-scroll-margin) 100)))
    (cond ((< beg margin) (recenter beg))
	  ((< (- beg lines) margin) (recenter margin)))))

(defun edt-bottom-check (beg lines)
  "Enforce scroll margin at the bottom of screen.
Argument BEG is the starting line number before cursor was moved.
Argument LINES is the number of lines the cursor moved toward the bottom."
  (let* ((height (window-height))
		 (margin (+ 1 (/ (* height edt-bottom-scroll-margin) 100)))
		 ;; subtract 1 from height because it includes mode line
		 (difference (- height margin 1)))
    (cond ((> beg difference) (recenter beg))
		  ((> (+ beg lines) difference) (recenter (- margin))))))

(defun edt-current-line nil
  "Return the vertical position of point in the selected window.
Top line is 0.  Counts each text line only once, even if it wraps."
  (+ (count-lines (window-start) (point)) (if (= (current-column) 0) 1 0) -1))

;;;###autoload
(defun edt-set-scroll-margins (top bottom)
  "Set scroll margins.
Argument TOP is the top margin in number of lines or percent of window.
Argument BOTTOM is the bottom margin in number of lines or percent of window."
  (interactive
   "sEnter top scroll margin (N lines or N%% or RETURN for current value): \
\nsEnter bottom scroll margin (N lines or N%% or RETURN for current value): ")
  ;; set top scroll margin
  (or (string= top "")
      (if (string= "%" (substring top -1))
	  (setq edt-top-scroll-margin (string-to-number top))
	(setq edt-top-scroll-margin
	      (/ (1- (+ (* (string-to-number top) 100) (window-height)))
		 (window-height)))))
  ;; set bottom scroll margin
  (or (string= bottom "")
      (if (string= "%" (substring bottom -1))
	  (setq edt-bottom-scroll-margin (string-to-number bottom))
	(setq edt-bottom-scroll-margin
	      (/ (1- (+ (* (string-to-number bottom) 100) (window-height)))
		 (window-height)))))
  ;; report scroll margin settings if running interactively
  (and (called-interactively-p 'interactive)
       (message "Scroll margins set.  Top = %s%%, Bottom = %s%%"
		edt-top-scroll-margin edt-bottom-scroll-margin)))


;;;;
;;;; ENHANCEMENTS AND ADDITIONS FOR EDT KEYPAD MODE
;;;;

;;;
;;; Several enhancements and additions to EDT keypad mode commands are
;;; provided here.  Some of these have been motivated by similar
;;; TPU/EVE and EVE-Plus commands.  Others are new.

;;;
;;; CHANGE DIRECTION
;;;

(defun edt-change-direction ()
  "Toggle movement direction."
  (interactive)
  (if (equal edt-direction-string edt-forward-string)
      (edt-backup)
    (edt-advance)))

;;;
;;; TOGGLE SELECT
;;;

(defun edt-toggle-select ()
  "Toggle to start (or cancel) text selection."
  (interactive)
  (if edt-select-mode
      (edt-reset)
    (edt-select)))

;;;
;;; SENTENCE
;;;

(defun edt-sentence-forward (num)
  "Move forward to start of next sentence.
Argument NUM is the positive number of sentences to move."
  (interactive "p")
  (edt-check-prefix num)
  (edt-with-position
   (if (eobp)
       (error "End of buffer")
     (forward-sentence num)
     (forward-word 1)
     (backward-sentence))
   (if (> (point) far)
       (if (zerop (setq left (save-excursion (forward-line height))))
           (recenter top-margin)
         (recenter (- left bottom-up-margin)))
     (and (> (point) bottom) (recenter bottom-margin)))))

(defun edt-sentence-backward (num)
  "Move backward to next sentence beginning.
Argument NUM is the positive number of sentences to move."
  (interactive "p")
  (edt-check-prefix num)
  (edt-with-position
   (if (eobp)
       (error "End of buffer")
     (backward-sentence num))
   (and (< (point) top) (recenter (min beg top-margin)))))

(defun edt-sentence (num)
  "Move in current direction to next sentence.
Argument NUM is the positive number of sentences to move."
  (interactive "p")
  (if (equal edt-direction-string edt-forward-string)
      (edt-sentence-forward num)
    (edt-sentence-backward num)))

;;;
;;; PARAGRAPH
;;;

(defun edt-paragraph-forward (num)
  "Move forward to beginning of paragraph.
Argument NUM is the positive number of paragraphs to move."
  (interactive "p")
  (edt-check-prefix num)
  (edt-with-position
   (while (> num 0)
     (forward-paragraph (+ num 1))
     (start-of-paragraph-text)
     (if (eolp)
         (forward-line 1))
     (setq num (1- num)))
   (if (> (point) far)
       (if (zerop (setq left (save-excursion (forward-line height))))
           (recenter top-margin)
         (recenter (- left bottom-up-margin)))
     (and (> (point) bottom) (recenter bottom-margin)))))

(defun edt-paragraph-backward (num)
  "Move backward to beginning of paragraph.
Argument NUM is the positive number of paragraphs to move."
  (interactive "p")
  (edt-check-prefix num)
  (edt-with-position
   (while (> num 0)
     (start-of-paragraph-text)
     (setq num (1- num)))
   (and (< (point) top) (recenter (min beg top-margin)))))

(defun edt-paragraph (num)
  "Move in current direction to next paragraph.
Argument NUM is the positive number of paragraphs to move."
  (interactive "p")
  (if (equal edt-direction-string edt-forward-string)
      (edt-paragraph-forward num)
    (edt-paragraph-backward num)))

;;;
;;; RESTORE KEY
;;;

(defun edt-restore-key ()
  "Restore last replaced key definition.
Definition is stored in `edt-last-replaced-key-definition'."
  (interactive)
  (if edt-last-replaced-key-definition
      (progn
        (let (edt-key-definition)
          (setq edt-key-definition
                (read-key-sequence "Press the key to be restored: "))
          (if (string-equal "\C-m" edt-key-definition)
              (message "Key not restored")
	    (progn
	      (define-key (current-global-map)
		edt-key-definition edt-last-replaced-key-definition)
              (message "Key definition for %s has been restored."
                       edt-key-definition)))))
    (error "No replaced key definition to restore!")))

;;;
;;; WINDOW TOP
;;;

(defun edt-window-top ()
  "Move the cursor to the top of the window."
  (interactive)
  (let ((start-column (current-column)))
    (move-to-window-line 0)
    (move-to-column start-column)))

;;;
;;; WINDOW BOTTOM
;;;

(defun edt-window-bottom ()
  "Move the cursor to the bottom of the window."
  (interactive)
  (let ((start-column (current-column)))
    (move-to-window-line (- (window-height) 2))
    (move-to-column start-column)))

;;;
;;; SCROLL WINDOW LINE
;;;

(defun edt-scroll-window-forward-line ()
  "Move window forward one line leaving cursor at position in window."
  (interactive)
  (scroll-up 1))

(defun edt-scroll-window-backward-line ()
  "Move window backward one line leaving cursor at position in window."
  (interactive)
  (scroll-down 1))

(defun edt-scroll-line ()
  "Move window one line in current direction."
  (interactive)
  (if (equal edt-direction-string edt-forward-string)
      (edt-scroll-window-forward-line)
    (edt-scroll-window-backward-line)))

;;;
;;; SCROLL WINDOW
;;;
;;; Scroll a window (less one line) at a time.  Leave cursor in center of
;;; window.

(defun edt-scroll-window-forward (num)
  "Scroll forward one window in buffer, less one line.
Argument NUM is the positive number of windows to move."
  (interactive "p")
  (edt-check-prefix num)
  (scroll-up (- (* (window-height) num) 2))
  (edt-line-forward (/ (- (window-height) 1) 2)))

(defun edt-scroll-window-backward (num)
  "Scroll backward one window in buffer, less one line.
Argument NUM is the positive number of windows to move."
  (interactive "p")
  (edt-check-prefix num)
  (scroll-down (- (* (window-height) num) 2))
  (edt-line-backward (/ (- (window-height) 1) 2)))

(defun edt-scroll-window (num)
  "Scroll one window in buffer, less one line, in current direction.
Argument NUM is the positive number of windows to move."
  (interactive "p")
  (if (equal edt-direction-string edt-forward-string)
      (edt-scroll-window-forward num)
    (edt-scroll-window-backward num)))

;;;
;;; LINE TO BOTTOM OF WINDOW
;;;

(defun edt-line-to-bottom-of-window ()
  "Move the current line to the bottom of the window."
  (interactive)
  (recenter -1))

;;;
;;; LINE TO TOP OF WINDOW
;;;

(defun edt-line-to-top-of-window ()
  "Move the current line to the top of the window."
  (interactive)
  (recenter 0))

;;;
;;; LINE TO MIDDLE OF WINDOW
;;;

(defun edt-line-to-middle-of-window ()
  "Move window so line with cursor is in the middle of the window."
  (interactive)
  (recenter '(4)))

;;;
;;; GOTO PERCENTAGE
;;;

(defun edt-goto-percentage (num)
  "Move to specified percentage in buffer from top of buffer.
Argument NUM is the percentage into the buffer to move."
  (interactive "NGoto-percentage: ")
  (if (or (> num 100) (< num 0))
      (error "Percentage %d out of range 0 < percent < 100" num)
    (goto-char (/ (* (point-max) num) 100))))

;;;
;;; FILL REGION
;;;

(defun edt-fill-region ()
  "Fill selected text."
  (interactive "*")
  (edt-check-selection)
  (fill-region (point) (mark)))

;;;
;;; INDENT OR FILL REGION
;;;

(defun edt-indent-or-fill-region ()
  "Fill region in text modes, indent region in programming language modes."
  (interactive "*")
  (if (string= paragraph-start "$\\|\f")
      (indent-region (point) (mark) nil)
    (fill-region (point) (mark))))


(declare-function c-mark-function "cc-cmds" ())
;;;
;;; MARK SECTION WISELY
;;;

(defun edt-mark-section-wisely ()
  "Mark the section in a manner consistent with the `major-mode'.
Uses `mark-defun' for Emacs-Lisp and Lisp, and for Fortran,
`c-mark-function' for C,
and `mark-paragraph' for other modes."
  (interactive)
  (if edt-select-mode
      (progn
        (edt-reset))
    (progn
      (cond  ((or (eq major-mode 'emacs-lisp-mode)
		  (eq major-mode 'fortran-mode)
		  (eq major-mode 'lisp-mode))
	      (mark-defun)
	      (message "Lisp defun selected"))
	     ((eq major-mode 'c-mode)
	      (c-mark-function)
	      (message "C function selected"))
	     (t (mark-paragraph)
		(message "Paragraph selected"))))))

;;;
;;; COPY
;;;

(defun edt-copy ()
  "Copy selected region to kill ring, but don't delete it!"
  (interactive)
  (edt-check-selection)
  (copy-region-as-kill (mark) (point))
  (edt-reset)
  (message "Selected text COPIED to kill ring"))

;;;
;;; CUT or COPY
;;;

(defun edt-cut-or-copy ()
  "Cuts (or copies) selected text to kill ring.
Cuts selected text if `buffer-read-only' is nil.
Copies selected text if `buffer-read-only' is t."
  (interactive)
  (if buffer-read-only
      (edt-copy)
    (edt-cut)))

;;;
;;; DELETE ENTIRE LINE
;;;

(defun edt-delete-entire-line ()
  "Delete entire line regardless of cursor position in the line."
  (interactive "*")
  (beginning-of-line)
  (edt-delete-line 1))

;;;
;;; DUPLICATE LINE
;;;

(defun edt-duplicate-line (num)
  "Duplicate the line of text containing the cursor.
Argument NUM is the number of times to duplicate the line."
  (interactive "*p")
  (edt-check-prefix num)
  (let ((old-column (current-column))
        (count num))
    (edt-delete-entire-line)
    (edt-undelete-line)
    (while (> count 0)
      (edt-undelete-line)
      (setq count (1- count)))
    (edt-line-forward num)
    (move-to-column old-column)))

;;;
;;; DUPLICATE WORD
;;;

(defun edt-duplicate-word()
  "Duplicate word (or rest of word) found directly above cursor, if any."
  (interactive "*")
  (let ((start (point))
        (start-column (current-column)))
    (forward-line -1)
    (move-to-column start-column)
    (if (and (not (equal start (point)))
             (not (eolp)))
        (progn
          (if (and (equal ?\t (preceding-char))
                   (< start-column (current-column)))
              (backward-char))
          (let ((beg (point)))
            (edt-one-word-forward)
            (setq edt-last-copied-word (buffer-substring beg (point))))
          (forward-line)
          (move-to-column start-column)
          (insert edt-last-copied-word))
      (progn
	(if (not (equal start (point)))
	    (forward-line))
	(move-to-column start-column)
	(error "Nothing to duplicate!")))))

;;;
;;; KEY NOT ASSIGNED
;;;

(defun edt-key-not-assigned ()
  "Displays message that key has not been assigned to a function."
  (interactive)
  (error "Key not assigned"))

;;;
;;; TOGGLE CAPITALIZATION OF WORD
;;;

(defun edt-toggle-capitalization-of-word ()
  "Toggle the capitalization of the current word and move forward to next."
  (interactive "*")
  (edt-one-word-forward)
  (edt-one-word-backward)
  (edt-change-case 1)
  (edt-one-word-backward)
  (edt-one-word-forward))

;;;
;;; ELIMINATE ALL TABS
;;;

(defun edt-eliminate-all-tabs ()
  "Convert all tabs to spaces in the entire buffer."
  (interactive "*")
  (untabify (point-min) (point-max))
  (message "TABS converted to SPACES"))

;;;
;;; DISPLAY THE TIME
;;;

(defun edt-display-the-time ()
  "Display the current time."
  (interactive)
  (message "%s" (current-time-string)))

;;;
;;; LEARN
;;;

(defun edt-learn ()
  "Learn a sequence of key strokes to bind to a key."
  (interactive)
  (if (eq defining-kbd-macro t)
      (edt-remember)
    (start-kbd-macro nil)))

;;;
;;; REMEMBER
;;;

(defun edt-remember ()
  "Store the sequence of key strokes started by `edt-learn' to a key."
  (interactive)
  (if (eq defining-kbd-macro nil)
      (error "Nothing to remember!")
    (progn
      (end-kbd-macro nil)
      (let (edt-key-definition)
        (setq edt-key-definition
              (read-key-sequence "Enter key for binding: "))
	(if (string-equal "\C-m" edt-key-definition)
	    (message "Key sequence not remembered")
	  (progn
            (setq edt-learn-macro-count (+ edt-learn-macro-count 1))
	    (setq edt-last-replaced-key-definition
		  (lookup-key (current-global-map)
			      edt-key-definition))
	    (define-key (current-global-map) edt-key-definition
	      (name-last-kbd-macro
	       (intern (concat "last-learned-sequence-"
			       (int-to-string edt-learn-macro-count)))))))))))

;;;
;;; EXIT
;;;

(defun edt-exit ()
  "Save current buffer, ask to save other buffers, and then exit Emacs."
  (interactive)
  (save-buffer)
  (save-buffers-kill-emacs))

;;;
;;; QUIT
;;;

(defun edt-quit ()
  "Quit Emacs without saving buffer modifications.
Warn user that modifications will be lost."
  (interactive)
  (let ((list (buffer-list))
	(working t))
    (while (and list working)
      (let ((buffer (car list)))
	(if (and (buffer-file-name buffer) (buffer-modified-p buffer))
            (if (edt-y-or-n-p
		 "Modifications will not be saved, continue quitting? ")
		(kill-emacs)
	      (setq working nil)))
	(setq list (cdr list))))
    (if working (kill-emacs))))

;;;
;;; SPLIT WINDOW
;;;

(defun edt-split-window ()
  "Split current window and place cursor in the new window."
  (interactive)
  (split-window)
  (other-window 1))

;;;
;;; COPY RECTANGLE
;;;

(defun edt-copy-rectangle ()
  "Copy a rectangle of text between mark and cursor to register."
  (interactive)
  (edt-check-selection)
  (copy-rectangle-to-register 3 (region-beginning) (region-end) nil)
  (edt-reset)
  (message "Selected rectangle COPIED to register"))

;;;
;;; CUT RECTANGLE
;;;

(defun edt-cut-rectangle-overstrike-mode ()
  "Cut a rectangle of text between mark and cursor to register.
Replace cut characters with spaces and moving cursor back to
upper left corner."
  (interactive "*")
  (edt-check-selection)
  (setq edt-rect-start-point (region-beginning))
  (picture-clear-rectangle-to-register (region-beginning) (region-end) 3)
  (set-window-point (get-buffer-window (window-buffer)) edt-rect-start-point)
  (message "Selected rectangle CUT to register"))

(defun edt-cut-rectangle-insert-mode ()
  "Cut a rectangle of text between mark and cursor to register.
Move cursor back to upper left corner."
  (interactive "*")
  (edt-check-selection)
  (setq edt-rect-start-point (region-beginning))
  (picture-clear-rectangle-to-register (region-beginning) (region-end) 3 t)
  (fixup-whitespace)
  (set-window-point (get-buffer-window (window-buffer)) edt-rect-start-point)
  (message "Selected rectangle CUT to register"))

(defun edt-cut-rectangle ()
  "Cut a rectangular region of text to register.
If overwrite mode is active, cut text is replaced with whitespace."
  (interactive "*")
  (if overwrite-mode
      (edt-cut-rectangle-overstrike-mode)
    (edt-cut-rectangle-insert-mode)))

;;;
;;; PASTE RECTANGLE
;;;

(defun edt-paste-rectangle-overstrike-mode ()
  "Paste a rectangular region of text from register, replacing text at cursor."
  (interactive "*")
  (picture-yank-rectangle-from-register 3))

(defun edt-paste-rectangle-insert-mode ()
  "Paste previously deleted rectangular region, inserting text at cursor."
  (interactive "*")
  (picture-yank-rectangle-from-register 3 t))

(defun edt-paste-rectangle ()
  "Paste a rectangular region of text.
If overwrite mode is active, existing text is replace with text from register."
  (interactive)
  (if overwrite-mode
      (edt-paste-rectangle-overstrike-mode)
    (edt-paste-rectangle-insert-mode)))

;;;
;;; DOWNCASE REGION
;;;

(defun edt-lowercase ()
  "Change specified characters to lower case.
If text selection IS active, then characters between the cursor and
mark are changed.  If text selection is NOT active, there are two
situations.  If the current direction is ADVANCE, then the word under
the cursor is changed to lower case and the cursor is moved to rest at
the beginning of the next word.  If the current direction is BACKUP,
the word prior to the word under the cursor is changed to lower case
and the cursor is left to rest at the beginning of that word."
  (interactive "*")
  (if edt-select-mode
      (progn
	(downcase-region (mark) (point)))
    (progn
      ;; Move to beginning of current word.
      (if (and
	   (not (bobp))
	   (not (eobp))
	   (not (bolp))
	   (not (eolp))
	   (not (eq ?\  (char-syntax (preceding-char))))
	   (not (memq (preceding-char) edt-word-entities))
	   (not (memq (following-char) edt-word-entities)))
	  (edt-one-word-backward))
      (if (equal edt-direction-string edt-backward-string)
	  (edt-one-word-backward))
      (let ((beg (point)))
	(edt-one-word-forward)
	(downcase-region beg (point)))
      (if (equal edt-direction-string edt-backward-string)
	  (edt-one-word-backward)))))

;;;
;;; UPCASE REGION
;;;

(defun edt-uppercase ()
  "Change specified characters to upper case.
If text selection IS active, then characters between the cursor and
mark are changed.  If text selection is NOT active, there are two
situations.  If the current direction is ADVANCE, then the word under
the cursor is changed to upper case and the cursor is moved to rest at
the beginning of the next word.  If the current direction is BACKUP,
the word prior to the word under the cursor is changed to upper case
and the cursor is left to rest at the beginning of that word."
  (interactive "*")
  (if edt-select-mode
      (progn
	(upcase-region (mark) (point)))
    (progn
      ;; Move to beginning of current word.
      (if (and
	   (not (bobp))
	   (not (eobp))
	   (not (bolp))
	   (not (eolp))
	   (not (eq ?\  (char-syntax (preceding-char))))
	   (not (memq (preceding-char) edt-word-entities))
	   (not (memq (following-char) edt-word-entities)))
	  (edt-one-word-backward))
      (if (equal edt-direction-string edt-backward-string)
	  (edt-one-word-backward))
      (let ((beg (point)))
	(edt-one-word-forward)
	(upcase-region beg (point)))
      (if (equal edt-direction-string edt-backward-string)
	  (edt-one-word-backward)))))

;;;
;;;  Functions used in loading LK-201 key mapping file.
;;;
(defvar edt-last-answer nil
  "Most recent response to `edt-y-or-n-p'.")

(defun edt-y-or-n-p (prompt &optional not-yes)
  "Prompt for a y or n answer with positive default.
Like Emacs `y-or-n-p', also accepts space as y and DEL as n.
Argument PROMPT is the prompt string.
Optional argument NOT-YES changes the default to negative."
  (message "%s[%s]" prompt (if not-yes "n" "y"))
  (let ((doit t))
    (while doit
      (setq doit nil)
      (let ((ans (read-char)))
	(cond ((or (= ans ?y) (= ans ?Y) (= ans ?\ ))
	       (setq edt-last-answer t))
	      ((or (= ans ?n) (= ans ?N) (= ans ?\C-?))
	       (setq edt-last-answer nil))
	      ((= ans ?\r) (setq edt-last-answer (not not-yes)))
	      (t
	       (setq doit t) (beep)
	       (message "Please answer y or n.  %s[%s]"
			prompt (if not-yes "n" "y")))))))
  edt-last-answer)

;;;
;;; INITIALIZATION COMMANDS.
;;;

(declare-function edt-mapper "edt-mapper" ())

;;;
;;;  Function used to load LK-201 key mapping file generated by edt-mapper.el.
;;;
(defun edt-load-keys (file)
  "Load the LK-201 key mapping FILE generated by edt-mapper.el.
If FILE is nil, which is the normal case, try to load a default file.
The default file names are based upon the window system and terminal
type.  If a default file does not exist, ask user if one should be
created."
  (interactive "fKey definition file: ")
  (cond (file
	 (setq file (expand-file-name file)))
	(edt-keys-file
	 (setq file (expand-file-name edt-keys-file)))
	(t
	 (setq file
	       (expand-file-name
		(concat
                 "~/.edt-gnu"
		 (if edt-term (concat "-" edt-term))
		 (if edt-xserver (concat "-" edt-xserver))
                 (if window-system
                     (concat "-" (upcase (symbol-name window-system))))
		 "-keys")))))
  (cond ((file-readable-p file)
	 (load-file file))
	(t
	 (switch-to-buffer "*scratch*")
	 (erase-buffer)
	 (insert "

     Ack!!  You're running the Enhanced EDT Emulation without loading an
     EDT key mapping file.  To create an EDT key mapping file, run the
     edt-mapper program.  It is safest to run it from an Emacs loaded
     without any of your own customizations found in your init file, etc.
     The reason for this is that some user customizations confuse edt-mapper.
     You can do this by quitting Emacs and then invoking Emacs again as
     follows:

          emacs -q -l edt-mapper -f edt-mapper

     [NOTE:  If you do nothing out of the ordinary in your init file, and
     the search for edt-mapper is successful, you can try running it now.]

     The library edt-mapper includes these same directions on how to
     use it!  Perhaps it's lying around here someplace. \n     ")
         (let ((path (locate-library
                      "edt-mapper"
                      nil (append (list default-directory) load-path))))
           (if path
               (progn
                 (insert (format
                          "Ah yes, there it is, in \n\n       %s \n\n" path))
                 (if (edt-y-or-n-p "Do you want to run it now? ")
                     (progn
                       (load-file path)
                       (edt-mapper))
                   (error "EDT Emulation not configured")))
             (insert (substitute-command-keys
		      "Nope, I can't seem to find it.  :-(\n\n"))
             (sit-for 20)
             (error "EDT Emulation not configured"))))))

;;;
;;;  Turning the EDT Emulation on and off.
;;;

;;;###autoload
(defun edt-emulation-on ()
  "Turn on EDT Emulation."
  (interactive)
  ;; If using pc window system (MS-DOS), set terminal type to pc.
  ;; If not a window system, get terminal type.
  (if (eq window-system 'pc)
      (setq edt-term "pc")
    (if (not window-system)
	(setq edt-term (getenv "TERM"))))
  ;; Look for a terminal configuration file for this terminal type.
  ;; Otherwise, load the user's custom configuration file.
  (if (or (not window-system) (memq window-system '(pc tty)))
      (progn
	;; Load terminal-specific configuration file, if it exists for this
	;; terminal type.  Note: All DEC VT series terminals are supported
	;; by the same terminal configuration file: edt-vt100.el.
	(if (string-equal "vt" (substring edt-term 0 (min (length edt-term) 2)))
	    (setq edt-term "vt100"))
	(let ((term edt-term)
	      hyphend)
	  (while (and term
		      (not (load (concat "edt-" term) t t)))
	    ;; Strip off last hyphen and what follows, then try again
	    (if (setq hyphend (string-match "[-_][^-_]+$" term))
		(setq term (substring term 0 hyphend))
	      (setq term nil)))
	  ;; If no terminal-specific configuration file exists, load user's
	  ;; custom EDT terminal configuration file.
	  ;; If this is a pc running MS-DOS, then custom configuration files
	  ;; are not supported.  So, if the file is missing, issue an error
	  ;; message.
	  (if (null term)
	      (if (equal edt-term "pc")
		  (error "Unable to find EDT terminal specific file edt-pc.el")
		(edt-load-keys nil))
	    (setq edt-term term))))
    (edt-load-keys nil))
  ;; Make highlighting of selected text work properly for EDT commands.
  (setq edt-orig-transient-mark-mode
        (default-value 'transient-mark-mode))
  (add-hook 'activate-mark-hook
            (lambda ()
              (edt-select-mode t)))
  (add-hook 'deactivate-mark-hook
            (lambda ()
              (edt-select-mode nil)))
  ;;  Load user's EDT custom key bindings file, if it exists.
  ;;  Otherwise, use the default bindings.
  (if (load "edt-user" t t)
      (edt-user-emulation-setup)
      (edt-default-emulation-setup)))

(defun edt-emulation-off()
  "Select original global key bindings, disabling EDT Emulation."
  (interactive)
  (use-global-map global-map)
  (if (not edt-keep-current-page-delimiter)
      (setq page-delimiter edt-orig-page-delimiter))
  (setq edt-direction-string "")
  (setq edt-select-mode-current nil)
  (edt-reset)
  (force-mode-line-update t)
  (setq-default transient-mark-mode edt-orig-transient-mark-mode)
  (message "Original key bindings restored; EDT Emulation disabled"))

(defun edt-default-menu-bar-update-buffers ()
  ;; Update edt-default-global-map with latest copy of
  ;; `global-buffers-menu-map' each time `menu-bar-update-buffers'
  ;; updates global-map.
  (define-key edt-default-global-map [menu-bar buffer]
    (cons "Buffers" global-buffers-menu-map)))

(defun edt-user-menu-bar-update-buffers ()
  ;; We need to update edt-user-global-map with latest copy of
  ;; `global-buffers-menu-map' each time `menu-bar-update-buffers'
  ;; updates global-map.
  (define-key edt-user-global-map [menu-bar buffer]
    (cons "Buffers" global-buffers-menu-map)))

(defun edt-default-emulation-setup (&optional user-setup)
  "Setup emulation of DEC's EDT editor.
Optional argument USER-SETUP non-nil means  called from function
`edt-user-emulation-setup'."
  ;; Setup default EDT global map by copying global map bindings.
  ;; This preserves ESC and C-x prefix bindings and other bindings we
  ;; wish to retain in EDT emulation mode keymaps.  It also permits
  ;; customization of these bindings in the EDT global maps without
  ;; disturbing the original bindings in global-map.
  (fset 'edt-default-ESC-prefix (copy-keymap 'ESC-prefix))
  (setq edt-default-global-map (copy-keymap (current-global-map)))
  (define-key edt-default-global-map "\e" 'edt-default-ESC-prefix)
  (define-prefix-command 'edt-default-gold-map)
  (edt-setup-default-bindings)
  ;; If terminal has additional function keys, the terminal-specific
  ;; initialization file can assign bindings to them via the optional
  ;; function edt-setup-extra-default-bindings.
  (if (fboundp 'edt-setup-extra-default-bindings)
      (edt-setup-extra-default-bindings))
  ;; Variable needed by edt-learn.
  (setq edt-learn-macro-count 0)
  ;; Display EDT text selection active within the mode line
  (or (assq 'edt-select-mode minor-mode-alist)
      (setq minor-mode-alist
	    (cons '(edt-select-mode edt-select-mode) minor-mode-alist)))
  ;; Display EDT direction of motion within the mode line
  (or (assq 'edt-direction-string minor-mode-alist)
      (setq minor-mode-alist
	    (cons
	     '(edt-direction-string edt-direction-string) minor-mode-alist)))
  (if user-setup
      (progn
        (setq edt-user-map-configured t)
        (fset 'edt-emulation-on (symbol-function 'edt-select-user-global-map)))
    (progn
      (fset 'edt-emulation-on (symbol-function 'edt-select-default-global-map))
      (edt-select-default-global-map)))
  ;; Keep the menu bar Buffers menu up-to-date in edt-default-global-map.
  (add-hook 'menu-bar-update-hook 'edt-default-menu-bar-update-buffers))

(defun edt-user-emulation-setup ()
  "Setup user custom emulation of DEC's EDT editor."
  ;; Initialize EDT default bindings.
  (edt-default-emulation-setup t)
  ;; Setup user EDT global map by copying default EDT global map bindings.
  (fset 'edt-user-ESC-prefix (copy-keymap 'edt-default-ESC-prefix))
  (setq edt-user-global-map (copy-keymap edt-default-global-map))
  (define-key edt-user-global-map "\e" 'edt-user-ESC-prefix)
  ;; If terminal has additional function keys, the user's initialization
  ;; file can assign bindings to them via the optional
  ;; function edt-setup-extra-default-bindings.
  (define-prefix-command 'edt-user-gold-map)
  (fset 'edt-user-gold-map (copy-keymap 'edt-default-gold-map))
  ;; This is a function that the user can define for custom bindings.
  ;; See Info node `edt' for more details, and sample edt-user.el file.
  (if (fboundp 'edt-setup-user-bindings)
      (edt-setup-user-bindings))
  (edt-select-user-global-map)
  ;; Keep the menu bar Buffers menu up-to-date in edt-user-global-map.
  (add-hook 'menu-bar-update-hook 'edt-user-menu-bar-update-buffers))

(defun edt-select-default-global-map()
  "Select default EDT emulation key bindings."
  (interactive)
  (transient-mark-mode 1)
  (use-global-map edt-default-global-map)
  (if (not edt-keep-current-page-delimiter)
      (progn
        (setq edt-orig-page-delimiter page-delimiter)
        (setq page-delimiter "\f")))
  (setq edt-default-map-active t)
  (edt-advance)
  (setq edt-select-mode-current 'edt-select-mode-string)
  (edt-reset)
  (message "Default EDT keymap active"))

(defun edt-select-user-global-map()
  "Select user EDT emulation custom key bindings."
  (interactive)
  (if edt-user-map-configured
      (progn
        (transient-mark-mode 1)
        (use-global-map edt-user-global-map)
        (if (not edt-keep-current-page-delimiter)
            (progn
              (setq edt-orig-page-delimiter page-delimiter)
              (setq page-delimiter "\f")))
        (setq edt-default-map-active nil)
        (edt-advance)
	(setq edt-select-mode-current 'edt-select-mode-string)
        (edt-reset)
        (message "User EDT custom keymap active"))
    (error "User EDT custom keymap NOT configured!")))

(defun edt-switch-global-maps ()
  "Toggle between default EDT keymap and user EDT keymap."
  (interactive)
  (if edt-default-map-active
      (edt-select-user-global-map)
    (edt-select-default-global-map)))

;;
;;  Functions used to set up DEFAULT bindings to EDT emulation functions.
;;

(defun edt-bind-function-key-default (function-key binding gold-binding)
  "Binds LK-201 function keys to default bindings in the EDT Emulator.
Argument FUNCTION-KEY is the name of the function key or keypad function key.
Argument BINDING is the Emacs function to be bound to <KEY>.
Argument GOLD-BINDING is the Emacs function to be bound to GOLD <KEY>."
  (let ((key (cdr (assoc function-key *EDT-keys*))))
    (if (and key (not (equal key "")))
	(progn
	  (define-key edt-default-global-map key binding)
	  (define-key 'edt-default-gold-map key gold-binding)))))

(defun edt-bind-key-default (key binding)
  "Bind key sequences to default bindings in the EDT Emulator.
Argument KEY is the name of a standard key or a function key.
Argument BINDING is the Emacs function to be bound to <KEY>."
  (define-key edt-default-global-map key binding))

(defun edt-bind-gold-key-default (key gold-binding)
  "Binds <GOLD> key sequences to default bindings in the EDT Emulator.
Argument KEY is the name of a standard key or a function key.
Argument GOLD-BINDING is the Emacs function to be bound to GOLD <KEY>."
  (define-key 'edt-default-gold-map key gold-binding))

;;
;;  Functions used to set up USER CUSTOM bindings to EDT emulation functions.
;;
(defun edt-bind-function-key (function-key binding gold-binding)
  "Binds LK-201 function keys to custom bindings in the EDT Emulator.
Argument FUNCTION-KEY is the name of the function key or keypad function key.
Argument BINDING is the Emacs function to be bound to <KEY>.
Argument GOLD-BINDING is the Emacs function to be bound to GOLD <KEY>."
  (let ((key (cdr (assoc function-key *EDT-keys*))))
    (if (and key (not (equal key "")))
	(progn
	  (define-key edt-user-global-map key binding)
	  (define-key 'edt-user-gold-map key gold-binding)))))

(defun edt-bind-key (key binding)
  "Bind standard key sequences to custom bindings in the EDT Emulator.
Argument KEY is the name of a key.  It can be a standard key or a function key.
Argument BINDING is the Emacs function to be bound to <KEY>."
  (define-key edt-user-global-map key binding))

(define-obsolete-function-alias 'edt-bind-standard-key #'edt-bind-key "28.1")

(defun edt-bind-gold-key (key gold-binding)
  "Binds <GOLD> standard key sequences to custom bindings in the EDT Emulator.
Argument KEY is the name of a standard key or a function key.
Argument GOLD-BINDING is the Emacs function to be bound to GOLD <KEY>."
  (define-key 'edt-user-gold-map key gold-binding))

(defun edt-setup-default-bindings ()
  "Assigns default EDT Emulation keyboard bindings."

  ;; Function Key Bindings:  Regular and GOLD.

  ;; VT100/VT200/VT300 PF1 (GOLD), PF2, PF3, PF4 Keys
  (edt-bind-function-key-default "PF1"
       'edt-default-gold-map 'edt-mark-section-wisely)
  (edt-bind-function-key-default "PF2"
       'edt-electric-keypad-help 'describe-function)
  (edt-bind-function-key-default "PF3" 'edt-find-next 'edt-find)
  (edt-bind-function-key-default "PF4" 'edt-delete-line 'edt-undelete-line)

  ;; VT100/VT200/VT300 Arrow Keys
  (edt-bind-function-key-default "UP" 'edt-previous-line 'edt-window-top)
  (edt-bind-function-key-default "DOWN" 'edt-next-line 'edt-window-bottom)
  (edt-bind-function-key-default "LEFT" 'backward-char 'edt-sentence-backward)
  (edt-bind-function-key-default "RIGHT" 'forward-char 'edt-sentence-forward)

  ;; VT100/VT200/VT300 Keypad Keys
  (edt-bind-function-key-default "KP0" 'edt-line 'open-line)
  (edt-bind-function-key-default "KP1" 'edt-word 'edt-change-case)
  (edt-bind-function-key-default "KP2"
       'edt-end-of-line 'edt-delete-to-end-of-line)
  (edt-bind-function-key-default "KP3" 'edt-character 'quoted-insert)
  (edt-bind-function-key-default "KP4" 'edt-advance 'edt-bottom)
  (edt-bind-function-key-default "KP5" 'edt-backup 'edt-top)
  (edt-bind-function-key-default "KP6" 'edt-cut 'yank)
  (edt-bind-function-key-default "KP7" 'edt-page 'execute-extended-command)
  (edt-bind-function-key-default "KP8" 'edt-sect 'edt-fill-region)
  (edt-bind-function-key-default "KP9" 'edt-append 'edt-replace)
  (edt-bind-function-key-default "KP-" 'edt-delete-word 'edt-undelete-word)
  (edt-bind-function-key-default "KP,"
       'edt-delete-character 'edt-undelete-character)
  (edt-bind-function-key-default "KPP" 'edt-select 'edt-reset)
  (edt-bind-function-key-default "KPE" 'other-window 'edt-substitute)

  ;; VT200/VT300 Function Keys
  ;; (F1 through F5, on the VT220, are not programmable, so we skip
  ;; making default bindings to those keys.
  (edt-bind-function-key-default "FIND" 'edt-find-next 'edt-find)
  (edt-bind-function-key-default "INSERT" 'yank 'edt-key-not-assigned)
  (edt-bind-function-key-default "REMOVE" 'edt-cut 'edt-copy)
  (edt-bind-function-key-default "SELECT"
       'edt-toggle-select 'edt-key-not-assigned)
  (edt-bind-function-key-default "NEXT"
       'edt-sect-forward 'edt-key-not-assigned)
  (edt-bind-function-key-default "PREVIOUS"
       'edt-sect-backward 'edt-key-not-assigned)
  (edt-bind-function-key-default "F6"
       'edt-key-not-assigned 'edt-key-not-assigned)
  (edt-bind-function-key-default "F7"
       'edt-copy-rectangle 'edt-key-not-assigned)
  (edt-bind-function-key-default "F8"
       'edt-cut-rectangle-overstrike-mode 'edt-paste-rectangle-overstrike-mode)
  (edt-bind-function-key-default "F9"
       'edt-cut-rectangle-insert-mode 'edt-paste-rectangle-insert-mode)
  (edt-bind-function-key-default "F10" 'edt-cut-rectangle 'edt-paste-rectangle)
  ;; Under X, the F11 key can be bound.  If using a VT-200 or higher terminal,
  ;; the default emacs terminal support causes the VT F11 key to seem as if it
  ;; is an ESC key when in emacs.
  (edt-bind-function-key-default "F11"
       'edt-key-not-assigned 'edt-key-not-assigned)
  (edt-bind-function-key-default "F12"
       'edt-beginning-of-line 'delete-other-windows) ;BS
  (edt-bind-function-key-default "F13"
       'edt-delete-to-beginning-of-word 'edt-key-not-assigned) ;LF
  (edt-bind-function-key-default "F14"
       'edt-key-not-assigned 'edt-key-not-assigned)
  (edt-bind-function-key-default "HELP"
       'edt-electric-keypad-help 'edt-key-not-assigned)
  (edt-bind-function-key-default "DO"
       'execute-extended-command 'edt-key-not-assigned)
  (edt-bind-function-key-default "F17"
       'edt-key-not-assigned 'edt-key-not-assigned)
  (edt-bind-function-key-default "F18"
       'edt-key-not-assigned 'edt-key-not-assigned)
  (edt-bind-function-key-default "F19"
       'edt-key-not-assigned 'edt-key-not-assigned)
  (edt-bind-function-key-default "F20"
       'edt-key-not-assigned 'edt-key-not-assigned)

  ;; Control key bindings:  Regular and GOLD
  ;;
  ;; Standard EDT control key bindings conflict with standard Emacs
  ;; control key bindings.  Normally, the standard Emacs control key
  ;; bindings are left unchanged in the default EDT mode.  However, if
  ;; the variable edt-use-EDT-control-key-bindings is set to true
  ;; before invoking edt-emulation-on for the first time, then the
  ;; standard EDT bindings (with some enhancements) as defined here are
  ;; used, instead.
  (if edt-use-EDT-control-key-bindings
      (progn
        (edt-bind-key-default "\C-a" 'edt-key-not-assigned)
        (edt-bind-key-default "\C-b" 'edt-key-not-assigned)
        ;; Leave binding of C-c to an Emacs prefix key.
        (edt-bind-key-default "\C-d" 'edt-key-not-assigned)
        (edt-bind-key-default "\C-e" 'edt-key-not-assigned)
        (edt-bind-key-default "\C-f" 'edt-key-not-assigned)
        ;; Leave binding of C-g to the Emacs keyboard-quit
        (edt-bind-key-default "\C-h" 'edt-beginning-of-line)
        (edt-bind-key-default "\C-i" 'edt-tab-insert)
        (edt-bind-key-default "\C-j" 'edt-delete-to-beginning-of-word)
        (edt-bind-key-default "\C-k" 'edt-define-key)
        (edt-bind-gold-key-default  "\C-k" 'edt-restore-key)
        (edt-bind-key-default "\C-l" 'edt-form-feed-insert)
        ;; Leave binding of C-m to newline.
        (edt-bind-key-default "\C-n" 'edt-set-screen-width-80)
        (edt-bind-key-default "\C-o" 'edt-key-not-assigned)
        (edt-bind-key-default "\C-p" 'edt-key-not-assigned)
        (edt-bind-key-default "\C-q" 'edt-key-not-assigned)
        ;; Leave binding of C-r to isearch-backward.
        ;; Leave binding of C-s to isearch-forward.
        (edt-bind-key-default "\C-t" 'edt-display-the-time)
        (edt-bind-key-default "\C-u" 'edt-delete-to-beginning-of-line)
        (edt-bind-key-default "\C-v" 'redraw-display)
        (edt-bind-key-default "\C-w" 'edt-set-screen-width-132)
        ;; Leave binding of C-x as original prefix key.
        (edt-bind-key-default "\C-y" 'edt-key-not-assigned)
        ;; Leave binding of C-z to suspend-emacs.
        )
      )

  ;; GOLD bindings for a few keys.
  (edt-bind-gold-key-default  "\C-g" 'keyboard-quit); Just in case.
  (edt-bind-gold-key-default  "\C-h" 'help-for-help); Just in case.
  (edt-bind-gold-key-default  [f1] 'help-for-help)
  (edt-bind-gold-key-default  [help] 'help-for-help)
  (edt-bind-gold-key-default  "\C-\\" 'split-window-below)

  ;; GOLD bindings for regular keys.
  (edt-bind-gold-key-default "a" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "A" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "b" 'buffer-menu)
  (edt-bind-gold-key-default "B" 'buffer-menu)
  (edt-bind-gold-key-default "c" 'compile)
  (edt-bind-gold-key-default "C" 'compile)
  (edt-bind-gold-key-default "d" 'delete-window)
  (edt-bind-gold-key-default "D" 'delete-window)
  (edt-bind-gold-key-default "e" 'edt-exit)
  (edt-bind-gold-key-default "E" 'edt-exit)
  (edt-bind-gold-key-default "f" 'find-file)
  (edt-bind-gold-key-default "F" 'find-file)
  (edt-bind-gold-key-default "g" 'find-file-other-window)
  (edt-bind-gold-key-default "G" 'find-file-other-window)
  (edt-bind-gold-key-default "h" 'edt-electric-keypad-help)
  (edt-bind-gold-key-default "H" 'edt-electric-keypad-help)
  (edt-bind-gold-key-default "i" 'insert-file)
  (edt-bind-gold-key-default "I" 'insert-file)
  (edt-bind-gold-key-default "j" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "J" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "k" 'edt-toggle-capitalization-of-word)
  (edt-bind-gold-key-default "K" 'edt-toggle-capitalization-of-word)
  (edt-bind-gold-key-default "l" 'edt-lowercase)
  (edt-bind-gold-key-default "L" 'edt-lowercase)
  (edt-bind-gold-key-default "m" 'save-some-buffers)
  (edt-bind-gold-key-default "M" 'save-some-buffers)
  (edt-bind-gold-key-default "n" 'next-error)
  (edt-bind-gold-key-default "N" 'next-error)
  (edt-bind-gold-key-default "o" 'switch-to-buffer-other-window)
  (edt-bind-gold-key-default "O" 'switch-to-buffer-other-window)
  (edt-bind-gold-key-default "p" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "P" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "q" 'edt-quit)
  (edt-bind-gold-key-default "Q" 'edt-quit)
  (edt-bind-gold-key-default "r" 'revert-buffer)
  (edt-bind-gold-key-default "R" 'revert-buffer)
  (edt-bind-gold-key-default "s" 'save-buffer)
  (edt-bind-gold-key-default "S" 'save-buffer)
  (edt-bind-gold-key-default "t" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "T" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "u" 'edt-uppercase)
  (edt-bind-gold-key-default "U" 'edt-uppercase)
  (edt-bind-gold-key-default "v" 'find-file-other-window)
  (edt-bind-gold-key-default "V" 'find-file-other-window)
  (edt-bind-gold-key-default "w" 'write-file)
  (edt-bind-gold-key-default "W" 'write-file)
  (edt-bind-gold-key-default "x" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "X" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "y" 'edt-emulation-off)
  (edt-bind-gold-key-default "Y" 'edt-emulation-off)
  (edt-bind-gold-key-default "z" 'edt-switch-global-maps)
  (edt-bind-gold-key-default "Z" 'edt-switch-global-maps)
  (edt-bind-gold-key-default "1" 'delete-other-windows)
  (edt-bind-gold-key-default "!" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "2" 'edt-split-window)
  (edt-bind-gold-key-default "@" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "3" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "#" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "4" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "$" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "5" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "%" 'edt-goto-percentage)
  (edt-bind-gold-key-default "6" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "^" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "7" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "&" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "8" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "*" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "9" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "(" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "0" 'edt-key-not-assigned)
  (edt-bind-gold-key-default ")" 'edt-key-not-assigned)
  (edt-bind-gold-key-default " " 'undo)
  (edt-bind-gold-key-default "," 'edt-key-not-assigned)
  (edt-bind-gold-key-default "<" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "." 'edt-key-not-assigned)
  (edt-bind-gold-key-default ">" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "/" 'query-replace)
  (edt-bind-gold-key-default "?" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "\\" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "|" 'edt-key-not-assigned)
  (edt-bind-gold-key-default ";" 'edt-key-not-assigned)
  (edt-bind-gold-key-default ":" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "'" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "\"" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "-" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "_" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "=" 'goto-line)
  (edt-bind-gold-key-default "+" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "[" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "{" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "]" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "}" 'edt-key-not-assigned)
  (edt-bind-gold-key-default "`" 'what-line)
  (edt-bind-gold-key-default "~" 'edt-key-not-assigned)
)

;;;
;;; DEFAULT EDT KEYPAD HELP
;;;

;;
;; Upper case commands in the keypad diagram below indicate that the
;; emulation should look and feel very much like EDT.  Lower case
;; commands are enhancements and/or additions to the EDT keypad
;; commands or are native Emacs commands.
;;

(defun edt-keypad-help ()
  "DEFAULT EDT Keypad Active.

   F7: Copy Rectangle             +----------+----------+----------+----------+
   F8: Cut Rect Overstrike        |Prev Line |Next Line |Bkwd Char |Frwd Char |
 G-F8: Paste Rect Overstrike      |   (UP)   |  (DOWN)  |  (LEFT)  | (RIGHT)  |
   F9: Cut Rect Insert            |Window Top|Window Bot|Bkwd Sent |Frwd Sent |
 G-F9: Paste Rect Insert          +----------+----------+----------+----------+
  F10: Cut Rectangle
G-F10: Paste Rectangle
  F11: ESC
  F12: Beginning of Line          +----------+----------+----------+----------+
G-F12: Delete Other Windows       |   GOLD   |   HELP   |  FNDNXT  |  DEL L   |
  F13: Delete to Begin of Word    |   (PF1)  |   (PF2)  |   (PF3)  |  (PF4)   |
 HELP: Keypad Help                |Mark Wisel|Desc Funct|   FIND   |  UND L   |
G-HELP: Emacs Help                +----------+----------+----------+----------+
   DO: Execute extended command   |   PAGE   |   SECT   |  APPEND  |  DEL W   |
  C-g: Keyboard Quit              |    (7)   |    (8)   |    (9)   |   (-)    |
G-C-g: Keyboard Quit              |Ex Ext Cmd|Fill Regio| REPLACE  |  UND W   |
  C-h: Beginning of Line          +----------+----------+----------+----------+
G-C-h: Emacs Help                 |  ADVANCE |  BACKUP  |   CUT    |  DEL C   |
  C-i: Tab Insert                 |    (4)   |    (5)   |    (6)   |   (,)    |
  C-j: Delete to Begin of Word    |   BOTTOM |    TOP   |   Yank   |  UND C   |
  C-k: Define Key                 +----------+----------+----------+----------+
G-C-k: Restore Key                |   WORD   |    EOL   |   CHAR   |   Next   |
  C-l: Form Feed Insert           |    (1)   |    (2)   |    (3)   |  Window  |
  C-n: Set Screen Width 80        | CHNGCASE |  DEL EOL |Quoted Ins|          !
  C-r: Isearch Backward           +---------------------+----------+  (ENTER) |
  C-s: Isearch Forward            |         LINE        |  SELECT  |          !
  C-t: Display the Time           |         (0)         |    (.)   |   SUBS   |
  C-u: Delete to Begin of Line    |      Open Line      |   RESET  |          |
  C-v: Redraw Display             +---------------------+----------+----------+
  C-w: Set Screen Width 132
  C-z: Suspend Emacs                    +----------+----------+----------+
G-C-\\: Split Window                     |  FNDNXT  |   Yank   |   CUT    |
                                        |  (FIND)  | (INSERT) | (REMOVE) |
  G-b: Buffer Menu                      |   FIND   |          |   COPY   |
  G-c: Compile                          +----------+----------+----------+
  G-d: Delete Window                    |SELECT/RES|SECT BACKW|SECT FORWA|
  G-e: Exit                             | (SELECT) |(PREVIOUS)|  (NEXT)  |
  G-f: Find File                        |          |          |          |
  G-g: Find File Other Window           +----------+----------+----------+
  G-h: Keypad Help
  G-i: Insert File
  G-k: Toggle Capitalization Word
  G-l: Downcase Region
  G-m: Save Some Buffers
  G-n: Next Error
  G-o: Switch to Next Window
  G-q: Quit
  G-r: Revert File
  G-s: Save Buffer
  G-u: Upcase Region
  G-v: Find File Other Window
  G-w: Write file
  G-y: EDT Emulation OFF
  G-z: Switch to User EDT Key Bindings
  G-1: Delete Other Windows
  G-2: Split Window
  G-%: Go to Percentage
  G- : Undo  (GOLD Spacebar)
  G-=: Go to Line
  G-`: What line
  G-/: Query-Replace"

  (interactive)
  (describe-function 'edt-keypad-help))

(defun edt-electric-helpify (fun)
  (let ((name "*Help*"))
    (if (save-window-excursion
          (let* ((p (symbol-function 'help-print-return-message))
                 (b (get-buffer name))
                 (m (buffer-modified-p b)))
            (and b (not (get-buffer-window b))
                 (setq b nil))
            (unwind-protect
                (progn
                  (message "%s..." (capitalize (symbol-name fun)))
                  (and b
                       (with-current-buffer b
                         (set-buffer-modified-p t)))
                  (fset 'help-print-return-message 'ignore)
                  (call-interactively fun)
                  (and (get-buffer name)
                       (get-buffer-window (get-buffer name))
                       (or (not b)
                           (not (eq b (get-buffer name)))
                           (not (buffer-modified-p b)))))
              (fset 'help-print-return-message p)
              (and b (buffer-name b)
                   (with-current-buffer b
                     (set-buffer-modified-p m))))))
        (with-electric-help 'delete-other-windows name t))))

(defun edt-electric-keypad-help ()
  "Display default EDT bindings."
  (interactive)
  (edt-electric-helpify 'edt-keypad-help))

(defun edt-electric-user-keypad-help ()
  "Display user custom EDT bindings."
  (interactive)
  (edt-electric-helpify 'edt-user-keypad-help))

;;;
;;; EDT emulation screen width commands.
;;
;; Some terminals require modification of terminal attributes when
;; changing the number of columns displayed, hence the fboundp tests
;; below.  These functions are defined in the corresponding terminal
;; specific file, if needed.

(defun edt-set-screen-width-80 ()
  "Set screen width to 80 columns."
  (interactive)
  (if (fboundp 'edt-set-term-width-80)
      (edt-set-term-width-80))
  (set-frame-width nil 80)
  (message "Terminal width 80"))

(defun edt-set-screen-width-132 ()
  "Set screen width to 132 columns."
  (interactive)
  (if (fboundp 'edt-set-term-width-132)
      (edt-set-term-width-132))
  (set-frame-width nil 132)
  (message "Terminal width 132"))

(provide 'edt)

;;; edt.el ends here