lisp/linum.el

   1 ;;; linum.el --- display line numbers in the left margin -*- lexical-binding: t -*-
   2
   3 ;; Copyright (C) 2008-2014 Free Software Foundation, Inc.
   4
   5 ;; Author: Markus Triska <markus.triska@gmx.at>
   6 ;; Maintainer: emacs-devel@gnu.org
   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 (defcustom linum-format 'dynamic
  48   "Format used to display line numbers.
  49 Either a format string like \"%7d\", `dynamic' to adapt the width
  50 as needed, or a function that is called with a line number as its
  51 argument and should evaluate to a string to be shown on that line.
  52 See also `linum-before-numbering-hook'."
  53   :group 'linum
  54   :type '(choice (string :tag "Format string")
  55                  (const :tag "Dynamic width" dynamic)
  56                  (function :tag "Function")))
  57
  58 (defface linum
  59   '((t :inherit (shadow default)))
  60   "Face for displaying line numbers in the display margin."
  61   :group 'linum)
  62
  63 (defcustom linum-eager t
  64   "Whether line numbers should be updated after each command.
  65 The conservative setting `nil' might miss some buffer changes,
  66 and you have to scroll or press \\[recenter-top-bottom] to update the numbers."
  67   :group 'linum
  68   :type 'boolean)
  69
  70 (defcustom linum-delay nil
  71   "Delay updates to give Emacs a chance for other changes."
  72   :group 'linum
  73   :type 'boolean)
  74
  75 ;;;###autoload
  76 (define-minor-mode linum-mode
  77   "Toggle display of line numbers in the left margin (Linum mode).
  78 With a prefix argument ARG, enable Linum mode if ARG is positive,
  79 and disable it otherwise.  If called from Lisp, enable the mode
  80 if ARG is omitted or nil.
  81
  82 Linum mode is a buffer-local minor mode."
  83   :lighter ""                           ; for desktop.el
  84   (if linum-mode
  85       (progn
  86         (if linum-eager
  87             (add-hook 'post-command-hook (if linum-delay
  88                                              'linum-schedule
  89                                            'linum-update-current) nil t)
  90           (add-hook 'after-change-functions 'linum-after-change nil t))
  91         (add-hook 'window-scroll-functions 'linum-after-scroll nil t)
  92         ;; Using both window-size-change-functions and
  93         ;; window-configuration-change-hook seems redundant. --Stef
  94         ;; (add-hook 'window-size-change-functions 'linum-after-size nil t)
  95         (add-hook 'change-major-mode-hook 'linum-delete-overlays nil t)
  96         (add-hook 'window-configuration-change-hook
  97                   ;; FIXME: If the buffer is shown in N windows, this
  98                   ;; will be called N times rather than once.  We should use
  99                   ;; something like linum-update-window instead.
 100                   'linum-update-current nil t)
 101         (linum-update-current))
 102     (remove-hook 'post-command-hook 'linum-update-current t)
 103     (remove-hook 'post-command-hook 'linum-schedule t)
 104     ;; (remove-hook 'window-size-change-functions 'linum-after-size t)
 105     (remove-hook 'window-scroll-functions 'linum-after-scroll t)
 106     (remove-hook 'after-change-functions 'linum-after-change t)
 107     (remove-hook 'window-configuration-change-hook 'linum-update-current t)
 108     (remove-hook 'change-major-mode-hook 'linum-delete-overlays t)
 109     (linum-delete-overlays)))
 110
 111 ;;;###autoload
 112 (define-globalized-minor-mode global-linum-mode linum-mode linum-on)
 113
 114 (defun linum-on ()
 115   (unless (minibufferp)
 116     (linum-mode 1)))
 117
 118 (defun linum-delete-overlays ()
 119   "Delete all overlays displaying line numbers for this buffer."
 120   (mapc #'delete-overlay linum-overlays)
 121   (setq linum-overlays nil)
 122   (dolist (w (get-buffer-window-list (current-buffer) nil t))
 123     (set-window-margins w 0 (cdr (window-margins w)))))
 124
 125 (defun linum-update-current ()
 126   "Update line numbers for the current buffer."
 127   (linum-update (current-buffer)))
 128
 129 (defun linum-update (buffer)
 130   "Update line numbers for all windows displaying BUFFER."
 131   (with-current-buffer buffer
 132     (when linum-mode
 133       (setq linum-available linum-overlays)
 134       (setq linum-overlays nil)
 135       (save-excursion
 136         (mapc #'linum-update-window
 137               (get-buffer-window-list buffer nil 'visible)))
 138       (mapc #'delete-overlay linum-available)
 139       (setq linum-available nil))))
 140
 141 (defun linum-update-window (win)
 142   "Update line numbers for the portion visible in window WIN."
 143   (goto-char (window-start win))
 144   (let ((line (line-number-at-pos))
 145         (limit (window-end win t))
 146         (fmt (cond ((stringp linum-format) linum-format)
 147                    ((eq linum-format 'dynamic)
 148                     (let ((w (length (number-to-string
 149                                       (count-lines (point-min) (point-max))))))
 150                       (concat "%" (number-to-string w) "d")))))
 151         (width 0))
 152     (run-hooks 'linum-before-numbering-hook)
 153     ;; Create an overlay (or reuse an existing one) for each
 154     ;; line visible in this window, if necessary.
 155     (while (and (not (eobp)) (< (point) limit))
 156       (let* ((str (if fmt
 157                       (propertize (format fmt line) 'face 'linum)
 158                     (funcall linum-format line)))
 159              (visited (catch 'visited
 160                         (dolist (o (overlays-in (point) (point)))
 161                           (when (equal-including-properties
 162                                  (overlay-get o 'linum-str) str)
 163                             (unless (memq o linum-overlays)
 164                               (push o linum-overlays))
 165                             (setq linum-available (delq o linum-available))
 166                             (throw 'visited t))))))
 167         (setq width (max width (length str)))
 168         (unless visited
 169           (let ((ov (if (null linum-available)
 170                         (make-overlay (point) (point))
 171                       (move-overlay (pop linum-available) (point) (point)))))
 172             (push ov linum-overlays)
 173             (overlay-put ov 'before-string
 174                          (propertize " " 'display `((margin left-margin) ,str)))
 175             (overlay-put ov 'linum-str str))))
 176       ;; Text may contain those nasty intangible properties, but that
 177       ;; shouldn't prevent us from counting those lines.
 178       (let ((inhibit-point-motion-hooks t))
 179         (forward-line))
 180       (setq line (1+ line)))
 181     (set-window-margins win width (cdr (window-margins win)))))
 182
 183 (defun linum-after-change (beg end _len)
 184   ;; update overlays on deletions, and after newlines are inserted
 185   (when (or (= beg end)
 186             (= end (point-max))
 187             (string-match-p "\n" (buffer-substring-no-properties beg end)))
 188     (linum-update-current)))
 189
 190 (defun linum-after-scroll (win _start)
 191   (linum-update (window-buffer win)))
 192
 193 ;; (defun linum-after-size (frame)
 194 ;;   (linum-after-config))
 195
 196 (defun linum-schedule ()
 197   ;; schedule an update; the delay gives Emacs a chance for display changes
 198   (run-with-idle-timer 0 nil #'linum-update-current))
 199
 200 ;; (defun linum-after-config ()
 201 ;;   (walk-windows (lambda (w) (linum-update (window-buffer w))) nil 'visible))
 202
 203 (defun linum-unload-function ()
 204   "Unload the Linum library."
 205   (global-linum-mode -1)
 206   ;; continue standard unloading
 207   nil)
 208
 209 (provide 'linum)
 210
 211 ;;; linum.el ends here