93 lines
3.1 KiB
EmacsLisp
93 lines
3.1 KiB
EmacsLisp
|
;;; guix-history.el --- History of buffer information
|
||
|
|
|
||
|
|
;; Copyright © 2014 Alex Kost <alezost@gmail.com>
|
||
|
|
|
||
|
|
;; This file is part of GNU Guix.
|
||
|
|
|
||
|
|
;; GNU Guix 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 Guix 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 this program. If not, see <http://www.gnu.org/licenses/>.
|
||
|
|
|
||
|
|
;;; Commentary:
|
||
|
|
|
||
|
|
;; This file provides support for history of buffers similar to the
|
||
|
|
;; history of a `help-mode' buffer.
|
||
|
|
|
||
|
|
;;; Code:
|
||
|
|
|
||
|
|
(require 'cl-macs)
|
||
|
|
|
||
|
|
(defvar-local guix-history-stack-item nil
|
||
|
|
"Current item of the history.
|
||
|
|
A list of the form (FUNCTION [ARGS ...]).
|
||
|
|
The item is used by calling (apply FUNCTION ARGS).")
|
||
|
|
(put 'guix-history-stack-item 'permanent-local t)
|
||
|
|
|
||
|
|
(defvar-local guix-history-back-stack nil
|
||
|
|
"Stack (list) of visited items.
|
||
|
|
Each element of the list has a form of `guix-history-stack-item'.")
|
||
|
|
(put 'guix-history-back-stack 'permanent-local t)
|
||
|
|
|
||
|
|
(defvar-local guix-history-forward-stack nil
|
||
|
|
"Stack (list) of items visited with `guix-history-back'.
|
||
|
|
Each element of the list has a form of `guix-history-stack-item'.")
|
||
|
|
(put 'guix-history-forward-stack 'permanent-local t)
|
||
|
|
|
||
|
|
(defvar guix-history-size 0
|
||
|
|
"Maximum number of items saved in history.
|
||
|
|
If 0, the history is disabled.")
|
||
|
|
|
||
|
|
(defun guix-history-add (item)
|
||
|
|
"Add ITEM to history."
|
||
|
|
(and guix-history-stack-item
|
||
|
|
(push guix-history-stack-item guix-history-back-stack))
|
||
|
|
(setq guix-history-forward-stack nil
|
||
|
|
guix-history-stack-item item)
|
||
|
|
(when (>= (length guix-history-back-stack)
|
||
|
|
guix-history-size)
|
||
|
|
(setq guix-history-back-stack
|
||
|
|
(cl-loop for elt in guix-history-back-stack
|
||
|
|
for i from 1 to guix-history-size
|
||
|
|
collect elt))))
|
||
|
|
|
||
|
|
(defun guix-history-replace (item)
|
||
|
|
"Replace current item in history with ITEM."
|
||
|
|
(setq guix-history-stack-item item))
|
||
|
|
|
||
|
|
(defun guix-history-goto (item)
|
||
|
|
"Go to the ITEM of history.
|
||
|
|
ITEM should have the form of `guix-history-stack-item'."
|
||
|
|
(or (listp item)
|
||
|
|
(error "Wrong value of history element"))
|
||
|
|
(setq guix-history-stack-item item)
|
||
|
|
(apply (car item) (cdr item)))
|
||
|
|
|
||
|
|
(defun guix-history-back ()
|
||
|
|
"Go back to the previous element of history in the current buffer."
|
||
|
|
(interactive)
|
||
|
|
(or guix-history-back-stack
|
||
|
|
(user-error "No previous element in history"))
|
||
|
|
(push guix-history-stack-item guix-history-forward-stack)
|
||
|
|
(guix-history-goto (pop guix-history-back-stack)))
|
||
|
|
|
||
|
|
(defun guix-history-forward ()
|
||
|
|
"Go forward to the next element of history in the current buffer."
|
||
|
|
(interactive)
|
||
|
|
(or guix-history-forward-stack
|
||
|
|
(user-error "No next element in history"))
|
||
|
|
(push guix-history-stack-item guix-history-back-stack)
|
||
|
|
(guix-history-goto (pop guix-history-forward-stack)))
|
||
|
|
|
||
|
|
(provide 'guix-history)
|
||
|
|
|
||
|
|
;;; guix-history.el ends here
|