lisp/mb-depth.el

   1 ;;; mb-depth.el --- Indicate minibuffer-depth in prompt -*- lexical-binding: t -*-
   2 ;;
   3 ;; Copyright (C) 2006-2018 Free Software Foundation, Inc.
   4 ;;
   5 ;; Author: Miles Bader <miles@gnu.org>
   6 ;; Keywords: convenience
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24 ;;
  25 ;; Defines the minor mode `minibuffer-depth-indicate-mode'.
  26 ;;
  27 ;; When active, any recursive use of the minibuffer will show
  28 ;; the recursion depth in the minibuffer prompt.  This is only
  29 ;; useful if `enable-recursive-minibuffers' is non-nil.
  30
  31 ;;; Code:
  32
  33 (defvar minibuffer-depth-indicator-function nil
  34   "If non-nil, function to set up the minibuffer depth indicator.
  35 It is called with one argument, the minibuffer depth,
  36 and must return a string.")
  37
  38 ;; An overlay covering the prompt.  This is a buffer-local variable in
  39 ;; each affected minibuffer.
  40 ;;
  41 (defvar minibuffer-depth-overlay)
  42 (make-variable-buffer-local 'minibuffer-depth-overlay)
  43
  44 ;; This function goes on minibuffer-setup-hook
  45 (defun minibuffer-depth-setup ()
  46   "Set up a minibuffer for `minibuffer-depth-indicate-mode'.
  47 The prompt should already have been inserted."
  48   (let ((depth (minibuffer-depth)))
  49     (when (> depth 1)
  50       (let ((pos (point-min)))
  51         (setq minibuffer-depth-overlay (make-overlay pos (1+ pos))))
  52       (overlay-put minibuffer-depth-overlay 'before-string
  53                    (if minibuffer-depth-indicator-function
  54                        (funcall minibuffer-depth-indicator-function depth)
  55                      (propertize (format "[%d]" depth) 'face 'highlight)))
  56       (overlay-put minibuffer-depth-overlay 'evaporate t))))
  57
  58 ;;;###autoload
  59 (define-minor-mode minibuffer-depth-indicate-mode
  60   "Toggle Minibuffer Depth Indication mode.
  61
  62 Minibuffer Depth Indication mode is a global minor mode.  When
  63 enabled, any recursive use of the minibuffer will show the
  64 recursion depth in the minibuffer prompt.  This is only useful if
  65 `enable-recursive-minibuffers' is non-nil."
  66   :global t
  67   :group 'minibuffer
  68   (if minibuffer-depth-indicate-mode
  69       ;; Enable the mode
  70       (add-hook 'minibuffer-setup-hook 'minibuffer-depth-setup)
  71     ;; Disable the mode
  72     (remove-hook 'minibuffer-setup-hook 'minibuffer-depth-setup)))
  73
  74 (provide 'mb-depth)
  75
  76 ;;; mb-depth.el ends here