lisp/linum.el

   1 ;;; linum.el --- display line numbers in the left margin -*- lexical-binding: t -*-
   2
   3 ;; Copyright (C) 2008-2012 Free Software Foundation, Inc.
   4
   5 ;; Author: Markus Triska <markus.triska@gmx.at>
   6 ;; Maintainer: FSF
   7 ;; Keywords: convenience
   8 ;; Version: 0.9x
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software: you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation, either version 3 of the License, or
  15 ;; (at your option) any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;; Display line numbers for the current buffer.
  28 ;;
  29 ;; Toggle display of line numbers with M-x linum-mode.  To enable
  30 ;; line numbering in all buffers, use M-x global-linum-mode.
  31
  32 ;;; Code:
  33
  34 (defconst linum-version "0.9x")
  35
  36 (defvar linum-overlays nil "Overlays used in this buffer.")
  37 (defvar linum-available nil "Overlays available for reuse.")
  38 (defvar linum-before-numbering-hook nil
  39   "Functions run in each buffer before line numbering starts.")
  40
  41 (mapc #'make-variable-buffer-local '(linum-overlays linum-available))
  42
  43 (defgroup linum nil
  44   "Show line numbers in the left margin."
  45   :group 'convenience)
  46
  47 ;;;###autoload
  48 (defcustom linum-format 'dynamic
  49   "Format used to display line numbers.
  50 Either a format string like \"%7d\", `dynamic' to adapt the width
  51 as needed, or a function that is called with a line number as its
  52 argument and should evaluate to a string to be shown on that line.
  53 See also `linum-before-numbering-hook'."
  54   :group 'linum
  55   :type 'sexp)
  56
  57 (defface linum
  58   '((t :inherit (shadow default)))
  59   "Face for displaying line numbers in the display margin."
  60   :group 'linum)
  61
  62 (defcustom linum-eager t
  63   "Whether line numbers should be updated after each command.
  64 The conservative setting `nil' might miss some buffer changes,
  65 and you have to scroll or press \\[recenter-top-bottom] to update the numbers."
  66   :group 'linum
  67   :type 'boolean)
  68
  69 (defcustom linum-delay nil
  70   "Delay updates to give Emacs a chance for other changes."
  71   :group 'linum
  72   :type 'boolean)
  73
  74 ;;;###autoload
  75 (define-minor-mode linum-mode
  76   "Toggle display of line numbers in the left margin (Linum mode).
  77 With a prefix argument ARG, enable Linum mode if ARG is positive,
  78 and disable it otherwise.  If called from Lisp, enable the mode
  79 if ARG is omitted or nil.
  80
  81 Linum mode is a buffer-local minor mode."
  82   :lighter ""                           ; for desktop.el
  83   (if linum-mode
  84       (progn
  85         (if linum-eager
  86             (add-hook 'post-command-hook (if linum-delay
  87                                              'linum-schedule
  88                                            'linum-update-current) nil t)
  89           (add-hook 'after-change-functions 'linum-after-change nil t))
  90         (add-hook 'window-scroll-functions 'linum-after-scroll nil t)
  91         ;; Using both window-size-change-functions and
  92         ;; window-configuration-change-hook seems redundant. --Stef
  93         ;; (add-hook 'window-size-change-functions 'linum-after-size nil t)
  94         (add-hook 'change-major-mode-hook 'linum-delete-overlays nil t)
  95         (add-hook 'window-configuration-change-hook
  96                   ;; FIXME: If the buffer is shown in N windows, this
  97                   ;; will be called N times rather than once.  We should use
  98                   ;; something like linum-update-window instead.
  99                   'linum-update-current nil t)
 100         (linum-update-current))
 101     (remove-hook 'post-command-hook 'linum-update-current t)
 102     (remove-hook 'post-command-hook 'linum-schedule t)
 103     ;; (remove-hook 'window-size-change-functions 'linum-after-size t)
 104     (remove-hook 'window-scroll-functions 'linum-after-scroll t)
 105     (remove-hook 'after-change-functions 'linum-after-change t)
 106     (remove-hook 'window-configuration-change-hook 'linum-update-current t)
 107     (remove-hook 'change-major-mode-hook 'linum-delete-overlays t)
 108     (linum-delete-overlays)))
 109
 110 ;;;###autoload
 111 (define-globalized-minor-mode global-linum-mode linum-mode linum-on)
 112
 113 (defun linum-on ()
 114   (unless (minibufferp)
 115     (linum-mode 1)))
 116
 117 (defun linum-delete-overlays ()
 118   "Delete all overlays displaying line numbers for this buffer."
 119   (mapc #'delete-overlay linum-overlays)
 120   (setq linum-overlays nil)
 121   (dolist (w (get-buffer-window-list (current-buffer) nil t))
 122     (set-window-margins w 0 (cdr (window-margins w)))))
 123
 124 (defun linum-update-current ()
 125   "Update line numbers for the current buffer."
 126   (linum-update (current-buffer)))
 127
 128 (defun linum-update (buffer)
 129   "Update line numbers for all windows displaying BUFFER."
 130   (with-current-buffer buffer
 131     (when linum-mode
 132       (setq linum-available linum-overlays)
 133       (setq linum-overlays nil)
 134       (save-excursion
 135         (mapc #'linum-update-window
 136               (get-buffer-window-list buffer nil 'visible)))
 137       (mapc #'delete-overlay linum-available)
 138       (setq linum-available nil))))
 139
 140 (defun linum-update-window (win)
 141   "Update line numbers for the portion visible in window WIN."
 142   (goto-char (window-start win))
 143   (let ((line (line-number-at-pos))
 144         (limit (window-end win t))
 145         (fmt (cond ((stringp linum-format) linum-format)
 146                    ((eq linum-format 'dynamic)
 147                     (let ((w (length (number-to-string
 148                                       (count-lines (point-min) (point-max))))))
 149                       (concat "%" (number-to-string w) "d")))))
 150         (width 0))
 151     (run-hooks 'linum-before-numbering-hook)
 152     ;; Create an overlay (or reuse an existing one) for each
 153     ;; line visible in this window, if necessary.
 154     (while (and (not (eobp)) (<= (point) limit))
 155       (let* ((str (if fmt
 156                       (propertize (format fmt line) 'face 'linum)
 157                     (funcall linum-format line)))
 158              (visited (catch 'visited
 159                         (dolist (o (overlays-in (point) (point)))
 160                           (when (equal-including-properties
 161                                  (overlay-get o 'linum-str) str)
 162                             (unless (memq o linum-overlays)
 163                               (push o linum-overlays))
 164                             (setq linum-available (delq o linum-available))
 165                             (throw 'visited t))))))
 166         (setq width (max width (length str)))
 167         (unless visited
 168           (let ((ov (if (null linum-available)
 169                         (make-overlay (point) (point))
 170                       (move-overlay (pop linum-available) (point) (point)))))
 171             (push ov linum-overlays)
 172             (overlay-put ov 'before-string
 173                          (propertize " " 'display `((margin left-margin) ,str)))
 174             (overlay-put ov 'linum-str str))))
 175       ;; Text may contain those nasty intangible properties, but that
 176       ;; shouldn't prevent us from counting those lines.
 177       (let ((inhibit-point-motion-hooks t))
 178         (forward-line))
 179       (setq line (1+ line)))
 180     (set-window-margins win width (cdr (window-margins win)))))
 181
 182 (defun linum-after-change (beg end _len)
 183   ;; update overlays on deletions, and after newlines are inserted
 184   (when (or (= beg end)
 185             (= end (point-max))
 186             (string-match-p "\n" (buffer-substring-no-properties beg end)))
 187     (linum-update-current)))
 188
 189 (defun linum-after-scroll (win _start)
 190   (linum-update (window-buffer win)))
 191
 192 ;; (defun linum-after-size (frame)
 193 ;;   (linum-after-config))
 194
 195 (defun linum-schedule ()
 196   ;; schedule an update; the delay gives Emacs a chance for display changes
 197   (run-with-idle-timer 0 nil #'linum-update-current))
 198
 199 ;; (defun linum-after-config ()
 200 ;;   (walk-windows (lambda (w) (linum-update (window-buffer w))) nil 'visible))
 201
 202 (defun linum-unload-function ()
 203   "Unload the Linum library."
 204   (global-linum-mode -1)
 205   ;; continue standard unloading
 206   nil)
 207
 208 (provide 'linum)
 209
 210 ;;; linum.el ends here