;;; echistory.el --- Electric Command History Mode

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

;; Author: K. Shane Hartman
;; Maintainer: FSF

;; This file is part of GNU Emacs.

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

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

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

;;; Code:

(require 'electric)			; command loop
(require 'chistory)			; history lister

;;;###autoload
(defun Electric-command-history-redo-expression (&optional noconfirm)
  "Edit current history line in minibuffer and execute result.
With prefix argument NOCONFIRM, execute current line as-is without editing."
  (interactive "P")
  (let (todo)
    (save-excursion
      (set-buffer "*Command History*")
      (beginning-of-line)
      (setq todo (read (current-buffer)))
      (if (boundp 'electric-history-in-progress)
	  (if todo (throw 'electric-history-quit (list noconfirm todo)))))))

(defvar electric-history-map ())
(if electric-history-map
    ()
  (setq electric-history-map (make-keymap))
  (set-keymap-name electric-history-map 'electric-history-map)
  (let ((i 0))
    (while (< i 128)
      (define-key electric-history-map (make-string 1 i)
	'Electric-history-undefined)
      (setq i (1+ i))))
  (let ((map (make-keymap))
	(i 0))
    ;;>>> Urk!  There should be a better way in Lucid Emacs!
    (define-key electric-history-map "\e" map)
    (while (< i 128)
      (define-key map (make-string 1 i) 'Electric-history-undefined)
      (setq i (1+ i))))
  (define-key electric-history-map "\C-u" 'universal-argument)
  (define-key electric-history-map " " 'Electric-command-history-redo-expression)
  (define-key electric-history-map "!" 'Electric-command-history-redo-expression)
  (define-key electric-history-map "\e\C-x" 'eval-sexp)
  (define-key electric-history-map "\e\C-d" 'down-list)
  (define-key electric-history-map "\e\C-u" 'backward-up-list)
  (define-key electric-history-map "\e\C-b" 'backward-sexp)
  (define-key electric-history-map "\e\C-f" 'forward-sexp)
  (define-key electric-history-map "\e\C-a" 'beginning-of-defun)
  (define-key electric-history-map "\e\C-e" 'end-of-defun)
  (define-key electric-history-map "\e\C-n" 'forward-list)
  (define-key electric-history-map "\e\C-p" 'backward-list)
  (define-key electric-history-map "q" 'Electric-history-quit)
  (define-key electric-history-map "\C-c" nil)
  (define-key electric-history-map "\C-c\C-c" 'Electric-history-quit)
  (define-key electric-history-map "\C-]" 'Electric-history-quit)
  (define-key electric-history-map "\C-z" 'suspend-emacs)
;;  (define-key electric-history-map "\C-h" 'Helper-help)
  (define-key electric-history-map '(control h) 'Helper-help)
  (define-key electric-history-map 'backspace 'previous-line)
  (define-key electric-history-map "?" 'Helper-describe-bindings)
  (define-key electric-history-map "\e>" 'end-of-buffer)
  (define-key electric-history-map "\e<" 'beginning-of-buffer)
  (define-key electric-history-map "\n" 'next-line)
  (define-key electric-history-map "\r" 'next-line)
  (define-key electric-history-map "\177" 'previous-line)  
  (define-key electric-history-map "\C-n" 'next-line)
  (define-key electric-history-map "\C-p" 'previous-line)
  (define-key electric-history-map "\ev" 'scroll-down)
  (define-key electric-history-map "\C-v" 'scroll-up)
  (define-key electric-history-map [home] 'beginning-of-buffer)
  (define-key electric-history-map [down] 'next-line)
  (define-key electric-history-map [up] 'previous-line)
  (define-key electric-history-map [prior] 'scroll-down)
  (define-key electric-history-map [next] 'scroll-up)
  (define-key electric-history-map "\C-l" 'recenter)
  (define-key electric-history-map "\e\C-v" 'scroll-other-window))

(defvar electric-command-history-hook nil
  "If non-nil, its value is called by `electric-command-history'.")

;;;###autoload
(defun electric-command-history ()
  "\\<electric-history-map>Major mode for examining and redoing commands from `command-history'.
This pops up a window with the Command History listing.
The number of command listed is controlled by `list-command-history-max'.
The command history is filtered by `list-command-history-filter' if non-nil.
Combines typeout Command History list window with menu like selection
of an expression from the history for re-evaluation in the *original* buffer.

The history displayed is filtered by `list-command-history-filter' if non-nil.

This pops up a window with the Command History listing.  If the very
next character typed is Space, the listing is killed and the previous
window configuration is restored.  Otherwise, you can browse in the
Command History with  Return  moving down and  Delete  moving up, possibly
selecting an expression to be redone with Space or quitting with `Q'.

Like Emacs-Lisp mode except that characters do not insert themselves and
Tab and Linefeed do not indent.  Instead these commands are provided:
\\{electric-history-map}

Calls the value of `electric-command-history-hook' if that is non-nil.
The Command History listing is recomputed each time this mode is invoked."
  (interactive)
  (let ((electric-history-in-progress t)
	(old-buffer (current-buffer))
	(todo))
    (unwind-protect
	(setq todo
	      (catch 'electric-history-quit
		(save-window-excursion
		  (save-window-excursion
		    (list-command-history)
		    (set-buffer "*Command History*")
		    (Command-history-setup 'electric-command-history
					   "Electric History"
					   electric-history-map))
		  (Electric-pop-up-window "*Command History*")
		  (run-hooks 'electric-command-history-hook)
		  (if (eobp)
		      (progn (ding)
			     (message "No command history.")
			     (throw 'electric-history-quit nil))
		    (let ((Helper-return-blurb "return to History"))
		      (Electric-command-loop 'electric-history-quit
					     "->" t))))))
      (set-buffer "*Command History*")
      (Command-history-setup)
      (bury-buffer (current-buffer)))
    (if (consp todo)
	(progn (set-buffer old-buffer)
	       (if (car todo)
		   (apply (car (car (cdr todo))) (cdr (car (cdr todo))))
		 (edit-and-eval-command "Redo: " (car (cdr todo))))))))

(defun Electric-history-undefined ()
  (interactive)
  (ding)
  (message (substitute-command-keys "Type \\[Help-for-help] for help, ? for commands, C-c to quit, Space to execute"))
  (sit-for 4))

(defun Electric-history-quit ()
  "Quit Electric Command History, restoring previous window configuration."
  (interactive)
  (if (boundp 'electric-history-in-progress)
      (progn (message nil)
	     (throw 'electric-history-quit nil))))

;;; echistory.el ends here