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;; chistory -- List command history
;; Copyright (C) 1985 Free Software Foundation, Inc.
;; Principal author K. Shane Hartman

;; 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 1, 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
;; 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.

(provide 'chistory)

;; This really has nothing to do with list-command-history per se, but
;; its a nice alternative to C-x ESC (repeat-complex-command) and
;; functions as a lister if given no pattern.  It's not important
;; enough to warrant a file of its own.

(defun repeat-matching-complex-command (&optional pattern)
  "Edit and re-evaluate complex command with name matching PATTERN.
Matching occurrences are displayed, most recent first, until you
select a form for evaluation.  If PATTERN is empty (or nil), every form
in the command history is offered.  The form is placed in the minibuffer
for editing and the result is evaluated."
  (interactive "sRedo Command (regexp): ")
  (if pattern
      (if (equal (setq pattern
		       (substring pattern
				  (or (string-match "[ \t]*[^ \t]" pattern)
				      (length pattern))))
	  (setq pattern nil)))
  (let ((history command-history)
    (while (and history (not what))
      (setq temp (car history))
      (if (and (or (not pattern) (string-match pattern (symbol-name (car temp))))
	       (y-or-n-p (format "Redo %s? " (setq temp (prin1-to-string temp)))))
	  (setq what (car history))
	(setq history (cdr history))))
    (if (not what)
	(error "Command history exhausted.")
      (edit-and-eval-command "Redo: " what))))

(defvar default-command-history-filter-garbage
  "*A list of symbols.  If  default-list-command-history-filter  is
given a list whose car is an element of this list, then it will return
non-nil (indicating the list should be discarded from the history).
Initially, all commands related to the command history are discarded.")

(defvar list-command-history-filter 'default-command-history-filter
  "If non-nil, should be the name of a function of one argument.
It is passed each element of the command history when
\\[list-command-history] is called.  If the filter returns non-nil for
some element, that element is excluded from the history listing.  The
default filter removes commands associated with the command-history.")

(defun default-command-history-filter (frob)
  "Filter commands matching  default-command-history-filter-garbage  list
from the command history."
  (or (not (consp frob))
      (memq (car frob) default-command-history-filter-garbage)))

(defvar list-command-history-max 32
  "*If non-nil, should be a positive number which specifies the maximum
length of the Command History listing produced by list-command-history.")

(defun list-command-history ()
  "List history of commands typed to minibuffer.
The number of commands listed is controlled by  list-command-history-max.
Calls value of  list-command-history-filter  (if non-nil) on each history
element to judge if that element should be excluded from the list.

The buffer is left in Command History mode."
      "*Command History*"
    (let ((history command-history)
	  (buffer-read-only nil)
	  (count (or list-command-history-max -1)))
      (while (and (/= count 0) history)
	(if (and (boundp 'list-command-history-filter)
		 (funcall list-command-history-filter (car history)))
	  (setq count (1- count))
	  (prin1 (car history))
	(setq history (cdr history))))
      (set-buffer "*Command History*")
      (goto-char (point-min))
      (if (eobp)
	  (error "No command history.")

(defun Command-history-setup (&optional majormode modename keymap)
  (set-buffer "*Command History*")
  (use-local-map (or keymap command-history-map))
  (lisp-mode-variables nil)
  (set-syntax-table emacs-lisp-mode-syntax-table)
  (setq buffer-read-only t)
  (use-local-map (or keymap command-history-map))
  (setq major-mode (or majormode 'command-history-mode))
  (setq mode-name (or modename "Command History")))

(defvar command-history-hook nil
  "If non-nil, its value is called on entry to  command-history-mode.")

(defvar command-history-map nil)
(if command-history-map
  (setq command-history-map (make-keymap))
  (lisp-mode-commands command-history-map)
  (suppress-keymap command-history-map)
  (define-key command-history-map "\n" 'next-line)
  (define-key command-history-map "\r" 'next-line)
  (define-key command-history-map "\177" 'previous-line))

(defun command-history-mode ()
  "Major mode for examining commands from  command-history.
The number of commands listed is controlled by  list-command-history-max.
The command history is filtered by  list-command-history-filter  if non-nil.

Like Emacs-Lisp Mode except that characters do not insert themselves and
Digits provide prefix arguments.  Tab does not indent.
Calls the value of  command-history-hook  if that is non-nil
The Command History listing is recomputed each time this mode is
  (pop-to-buffer "*Command History*")
  (run-hooks 'command-history-hook))