(describe_syntax): Add code for comment and string fences.
[emacs.git] / lisp / which-func.el
blob1a52b1c167ed38aadc11b614c6aa59325ad388b5
1 ;;; which-func.el --- Print current function in mode line
3 ;; Copyright (C) 1994, 1997, 1998 Free Software Foundation, Inc.
5 ;; Author: Alex Rezinsky <alexr@msil.sps.mot.com>
6 ;; Keywords: mode-line, imenu, tools
8 ;; This file is part of GNU Emacs.
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 2, or (at your option)
13 ;; any later version.
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.
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs; see the file COPYING. If not, write to the
22 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23 ;; Boston, MA 02111-1307, USA.
25 ;;; Commentary:
27 ;; This package prints name of function where your current point is
28 ;; located in mode line. It assumes that you work with imenu package
29 ;; and imenu--index-alist is up to date.
31 ;; KNOWN BUGS
32 ;; ----------
33 ;; Really this package shows not "function where the current point is
34 ;; located now", but "nearest function which defined above the current
35 ;; point". So if your current point is located after end of function
36 ;; FOO but before begin of function BAR, FOO will be displayed in mode
37 ;; line.
39 ;; TODO LIST
40 ;; ---------
41 ;; 1. Dependence on imenu package should be removed. Separate
42 ;; function determination mechanism should be used to determine the end
43 ;; of a function as well as the beginning of a function.
44 ;; 2. This package should be realized with the help of overlay
45 ;; properties instead of imenu--index-alist variable.
47 ;;; History:
49 ;; THANKS TO
50 ;; ---------
51 ;; Per Abrahamsen <abraham@iesd.auc.dk>
52 ;; Some ideas (inserting in mode-line, using of post-command hook
53 ;; and toggling this mode) have been borrowed from his package
54 ;; column.el
55 ;; Peter Eisenhauer <pipe@fzi.de>
56 ;; Bug fixing in case nested indexes.
57 ;; Terry Tateyama <ttt@ursa0.cs.utah.edu>
58 ;; Suggestion to use find-file-hooks for first imenu
59 ;; index building.
61 ;;; Code:
63 ;; Variables for customization
64 ;; ---------------------------
65 ;;
66 (defvar which-func-unknown "???"
67 "String to display in the mode line when current function is unknown.")
69 (defgroup which-func nil
70 "Mode to display the current function name in the modeline."
71 :group 'tools
72 :version "20.3")
74 (defcustom which-func-modes
75 '(emacs-lisp-mode c-mode c++-mode perl-mode makefile-mode sh-mode
76 fortran-mode)
77 "List of major modes for which Which Function mode should be used.
78 For other modes it is disabled. If this is equal to t,
79 then Which Function mode is enabled in any major mode that supports it."
80 :group 'which-func
81 :type '(choice (const :tag "All modes" t)
82 (repeat (symbol :tag "Major mode"))))
84 (defcustom which-func-non-auto-modes nil
85 "List of major modes where Which Function mode is inactive till Imenu is used.
86 This means that Which Function mode won't really do anything
87 until you use Imenu, in these modes. Note that files
88 larger than `which-func-maxout' behave in this way too;
89 Which Function mode doesn't do anything until you use Imenu."
90 :group 'which-func
91 :type '(repeat (symbol :tag "Major mode")))
93 (defcustom which-func-maxout 100000
94 "Don't automatically compute the Imenu menu if buffer is this big or bigger.
95 Zero means compute the Imenu menu regardless of size."
96 :group 'which-func
97 :type 'integer)
99 (defcustom which-func-format '("[" which-func-current "]")
100 "Format for displaying the function in the mode line."
101 :group 'which-func
102 :type 'sexp)
104 ;;;###autoload
105 (defcustom which-func-mode-global nil
106 "*Toggle `which-func-mode' globally.
107 Setting this variable directly does not take effect;
108 use either \\[customize] or the function `which-func-mode'."
109 :set #'(lambda (symbol value)
110 (which-func-mode (if value 1 0)))
111 :initialize 'custom-initialize-default
112 :type 'boolean
113 :group 'which-func
114 :require 'which-func)
116 (defvar which-func-cleanup-function nil
117 "Function to transform a string before displaying it in the mode line.
118 The function is called with one argument, the string to display.
119 Its return value is displayed in the modeline.
120 If nil, no function is called. The default value is nil.
122 This feature can be useful if Imenu is set up to make more
123 detailed entries (e.g., containing the argument list of a function),
124 and you want to simplify them for the mode line
125 \(e.g., removing the parameter list to just have the function name.)")
127 ;;; Code, nothing to customize below here
128 ;;; -------------------------------------
130 (require 'imenu)
132 (defvar which-func-current which-func-unknown)
133 (defvar which-func-previous which-func-unknown)
134 (make-variable-buffer-local 'which-func-current)
135 (make-variable-buffer-local 'which-func-previous)
137 (defvar which-func-mode nil
138 "Non-nil means display current function name in mode line.
139 This makes a difference only if `which-func-mode-global' is non-nil")
140 (make-variable-buffer-local 'which-func-mode)
141 ;;(put 'which-func-mode 'permanent-local t)
143 (add-hook 'find-file-hooks 'which-func-ff-hook t)
145 (defun which-func-ff-hook ()
146 "File find hook for Which Function mode.
147 It creates the Imenu index for the buffer, if necessary."
148 (setq which-func-mode
149 (and which-func-mode-global
150 (or (eq which-func-modes t) (member major-mode which-func-modes))))
152 (condition-case nil
153 (if (and which-func-mode
154 (not (member major-mode which-func-non-auto-modes))
155 (or (null which-func-maxout)
156 (< buffer-saved-size which-func-maxout)
157 (= which-func-maxout 0)))
158 (setq imenu--index-alist
159 (save-excursion (funcall imenu-create-index-function))))
160 (error
161 (setq which-func-mode nil))))
163 (defun which-func-update ()
164 ;; Update the string containing the current function.
165 (when which-func-mode
166 (condition-case info
167 (progn
168 (setq which-func-current (or (which-function) which-func-unknown))
169 (unless (string= which-func-current which-func-previous)
170 (force-mode-line-update)
171 (setq which-func-previous which-func-current)))
172 (error
173 (which-func-mode -1)
174 (error "Error in which-func-update: %s" info)))))
176 ;; This is the name people would normally expect.
177 ;;;###autoload
178 (defalias 'which-function-mode 'which-func-mode)
180 ;;;###autoload
181 (defun which-func-mode (&optional arg)
182 "Toggle Which Function mode, globally.
183 When Which Function mode is enabled, the current function name is
184 continuously displayed in the mode line, in certain major modes.
186 With prefix ARG, turn Which Function mode on iff arg is positive,
187 and off otherwise."
188 (interactive "P")
189 (setq which-func-mode-global
190 (or (and (null arg) which-func-mode-global)
191 (<= (prefix-numeric-value arg) 0)))
192 (if which-func-mode-global
193 ;; Turn it off
194 (progn
195 (remove-hook 'post-command-idle-hook 'which-func-update)
196 (dolist (buf (buffer-list))
197 (with-current-buffer buf (setq which-func-mode nil))))
198 ;;Turn it on
199 (add-hook 'post-command-idle-hook 'which-func-update)
200 (dolist (buf (buffer-list))
201 (with-current-buffer buf
202 (setq which-func-mode
203 (or (eq which-func-modes t)
204 (member major-mode which-func-modes)))))))
206 (defun which-function ()
207 "Return current function name based on point.
208 If `imenu--index-alist' does not exist, or is empty or if point
209 is located before first function, returns nil."
210 (let (name)
211 ;; First try using imenu support.
212 (when (and (boundp 'imenu--index-alist) imenu--index-alist)
213 (let ((pair (car-safe imenu--index-alist))
214 (rest (cdr-safe imenu--index-alist)))
215 (while (and (or rest pair)
216 (or (not (number-or-marker-p (cdr pair)))
217 (> (point) (cdr pair))))
218 (setq name (car pair))
219 (setq pair (car-safe rest))
220 (setq rest (cdr-safe rest)))))
221 ;; Try using add-log support.
222 (when (and (null name) (boundp 'add-log-current-defun-function)
223 add-log-current-defun-function)
224 (setq name (funcall add-log-current-defun-function)))
225 ;; Filter the name if requested.
226 (when name
227 (if which-func-cleanup-function
228 (funcall which-func-cleanup-function name)
229 name))))
231 (provide 'which-func)
233 ;; which-func.el ends here