root/trunk/lisp/emulation/edt.el

;;; edt.el --- enhanced EDT keypad mode emulation for GNU Emacs 19

;; Copyright (C) 1986, 1992, 1993, 1994, 1995, 2000, 2001, 2002, 2003,
;;   2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.

;; Author: Kevin Gallagher <Kevin.Gallagher@boeing.com>
;; Maintainer: Kevin Gallagher <Kevin.Gallagher@boeing.com>
;; 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, 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, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.



;;; Commentary:
;;

;; This is Version 4.0 of the EDT Emulation for Emacs 19 and above.
;; 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 .emacs file:
;;
;;    (add-hook term-setup-hook 'edt-emulation-on)

;; IMPORTANT: Be sure to read the file, edt-user.doc, located in the
;; Emacs "etc" directory.  It contains very helpful user information.

;; The EDT emulation consists of the following files:
;;
;; edt-user.doc     - User Instructions and Sample Customization File
;; 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 .emacs 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 (not available in Emacs 19) 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 edt-user.doc
;;      for details.

;;  3.  EDT Emulation now also works in XEmacs, including the
;;      highlighting of selected text.

;;  4.  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.

;;  5.  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.)

;;  6.  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
;;;;

;; For backward compatibility to Emacs 19.
(or (fboundp 'defgroup)
    (defmacro defgroup (&rest rest)))

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

;; To silence the byte-compiler
(eval-when-compile
  (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)
  (defvar time-string)
  (defvar zmacs-region-stays))

;;;
;;;  Version Information
;;;
(defconst edt-version "4.0" "EDT Emulation version number.")

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

;; For backward compatibility to Emacs 19.
(or (fboundp 'defcustom)
    (defmacro defcustom (var value doc &rest ignore)
      `(defvar ,var ,value ,doc)))

(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-emacs19-p (not (string-lessp emacs-version "19"))
  "Non-nil if we are running GNU Emacs or XEmacs version 19, or higher.")

(defconst edt-x-emacs19-p
  (and edt-emacs19-p (string-match "XEmacs" emacs-version))
  "Non-nil if we are running XEmacs version 19, or higher.")

(defconst edt-gnu-emacs19-p (and edt-emacs19-p (not edt-x-emacs19-p))
  "Non-nil if we are running GNU Emacs version 19, or higher.")

(defconst edt-emacs-variant (if edt-gnu-emacs19-p "gnu" "xemacs")
  "Indicates Emacs variant:  GNU Emacs or XEmacs \(aka Lucid Emacs\).")

(defconst edt-window-system (if edt-gnu-emacs19-p window-system (console-type))
  "Indicates window system \(in GNU Emacs\) or console type \(in XEmacs\).")

(defconst edt-xserver (if (eq edt-window-system 'x)
                          (if edt-x-emacs19-p
                              ;; 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-in-string (x-server-vendor) "[ /]" "-")
                            (subst-char-in-string ?/ ?- (subst-char-in-string ?  ?- (x-server-vendor))))
                        nil)
  "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.")

(defvar zmacs-region-stays)

;;;;
;;;; 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 .emacs 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)
          (if edt-x-emacs19-p (setq zmacs-region-stays t)))))

(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))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))


;;;
;;; 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))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))


(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))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))


(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 where ever 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))))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))

(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)))))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))

(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))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))

;;;
;;; 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))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))

(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)))
    (next-line num)
    (edt-bottom-check beg num))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))

(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)))
    (previous-line num)
    (edt-top-check beg num))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))


;;;
;;; TOP
;;;

(defun edt-top ()
  "Move cursor to the beginning of buffer."
  (interactive)
  (goto-char (point-min))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))

;;;
;;; BOTTOM
;;;

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

;;;
;;; 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)
  (if (not find)
      (set 'edt-find-last-text (read-string "Search forward: ")))
  (let* ((left nil)
         (beg (edt-current-line))
         (height (window-height))
         (top-percent
          (if (= 0 edt-top-scroll-margin) 10 edt-top-scroll-margin))
         (bottom-percent
          (if (= 0 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) (forward-line (- height 2)) (point))))
    (if (search-forward edt-find-last-text)
        (progn
          (search-backward edt-find-last-text)
          (edt-set-match)
          (cond((> (point) far)
                (setq left (save-excursion (forward-line height)))
                (if (= 0 left) (recenter top-margin)
                  (recenter (- left bottom-up-margin))))
               (t
                (and (> (point) bottom) (recenter bottom-margin)))))))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))

(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)
  (if (not find)
      (set 'edt-find-last-text (read-string "Search backward: ")))
  (let* ((left nil)
         (beg (edt-current-line))
         (height (window-height))
         (top-percent
          (if (= 0 edt-top-scroll-margin) 10 edt-top-scroll-margin))
         (bottom-percent
          (if (= 0 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) (forward-line (- height 2)) (point))))
    (if (search-backward edt-find-last-text)
        (edt-set-match))
    (and (< (point) top) (recenter (min beg top-margin))))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))

(defun edt-find ()
  "Find first occurrence of string in current direction and save it."
  (interactive)
  (set '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)
  (let* ((left nil)
         (beg (edt-current-line))
         (height (window-height))
         (top-percent
          (if (= 0 edt-top-scroll-margin) 10 edt-top-scroll-margin))
         (bottom-percent
          (if (= 0 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) (forward-line (- height 2)) (point))))
    (forward-char 1)
    (if (search-forward edt-find-last-text nil t)
        (progn
          (search-backward edt-find-last-text)
          (edt-set-match)
          (cond((> (point) far)
                (setq left (save-excursion (forward-line height)))
                (if (= 0 left) (recenter top-margin)
                  (recenter (- left bottom-up-margin))))
               (t
                (and (> (point) bottom) (recenter bottom-margin)))))
      (progn
        (backward-char 1)
        (error "Search failed: \"%s\"" edt-find-last-text))))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))

(defun edt-find-next-backward ()
  "Find next occurrence of a string in backward direction."
  (interactive)
  (let* ((left nil)
         (beg (edt-current-line))
         (height (window-height))
         (top-percent
          (if (= 0 edt-top-scroll-margin) 10 edt-top-scroll-margin))
         (bottom-percent
          (if (= 0 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) (forward-line (- height 2)) (point))))
    (if (not (search-backward edt-find-last-text nil t))
        (error "Search failed: \"%s\"" edt-find-last-text)
      (progn
        (edt-set-match)
        (and (< (point) top) (recenter (min beg top-margin))))))
  (if edt-x-emacs19-p (setq zmacs-region-stays t)))

(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