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(defun display-line-numbers ()
"Temporarily display line numbers in left margin of current buffer."
(interactive)
(or (eq (current-buffer) (window-buffer (selected-window)))
(error "Current buffer, %s, is not the selected window's buffer"
(buffer-name)))
(let ((buffer-read-only nil)
(modified (buffer-modified-p))
(name buffer-file-name)
(point (point-marker))
format-string
line-number
(count 0)
nlines
first-line)
(save-restriction
(widen)
(save-excursion
(setq first-line (window-start (selected-window)))
(goto-char first-line)
(setq line-number (1+ (count-lines (point-min) (point))))
(move-to-window-line -1)
(beginning-of-line)
(setq nlines (count-lines first-line (point)))
(let ((max (+ line-number nlines)))
(setq format-string (cond ((< max 100) "%2d ")
((< max 1000) "%3d ")
((< max 10000) "%4d ")
(t "%7d "))))))
(save-excursion
(unwind-protect
(progn
(goto-char first-line)
(setq buffer-file-name nil)
(while (<= count nlines)
(insert-before-markers (format format-string line-number))
(setq line-number (1+ line-number))
(setq count (1+ count))
(forward-line 1))
(set-window-start (selected-window) first-line)
(goto-char point)
(set-buffer-modified-p modified)
(message "<<< Press SPACE to continue >>>")
(let ((char (read-char)))
(or (eql char ?\ )
(setq unread-command-events (list char))))
)
(goto-char first-line)
(let ((n (1+ (- (aref format-string 1) ?0))))
(while (> count 0)
(setq count (1- count))
(delete-char n)
(forward-line 1)))
(setq buffer-file-name name)
(set-buffer-modified-p modified)))))
(defvar displaying-line-numbers-p nil)
(make-variable-buffer-local 'displaying-line-numbers-p)
(defvar display-line-numbers-format-string nil)
(make-variable-buffer-local 'display-line-numbers-format-string)
(defvar display-line-numbers-first-line nil)
(make-variable-buffer-local 'display-line-numbers-first-line)
(defvar display-line-numbers-count 0)
(make-variable-buffer-local 'display-line-numbers-count)
(defvar display-line-numbers-buffer-name nil)
(make-variable-buffer-local 'display-line-numbers-buffer-name)
(defvar display-line-numbers-modified-p nil)
(make-variable-buffer-local 'display-line-numbers-modified-p)
(defun toggle-line-numbers-display (arg)
"Display/clear line numbers in left margin of current buffer.
With prefix ARG, just number lines in current window, not all lines in
buffer."
(interactive "P")
(if displaying-line-numbers-p
(turn-off-line-numbers-display)
(turn-on-line-numbers-display arg)))
(defun turn-on-line-numbers-display (arg)
"Display line numbers in left margin of current buffer.
With prefix ARG, just number lines in current window, not all lines in
buffer."
(interactive "P")
(or (eq (current-buffer) (window-buffer (selected-window)))
(error "Current buffer, %s, is not the selected window's buffer"
(buffer-name)))
(let ((buffer-read-only nil)
(point (point-marker))
line-number
nlines)
(setq display-line-numbers-buffer-name buffer-file-name)
(setq display-line-numbers-modified-p (buffer-modified-p))
(save-restriction
(widen)
(save-excursion
(setq display-line-numbers-first-line
(if arg
(window-start (selected-window))
(point-min)))
(goto-char display-line-numbers-first-line)
(setq line-number (1+ (count-lines (point-min) (point))))
(if arg
(move-to-window-line -1)
(goto-char (point-max)))
(beginning-of-line)
(setq nlines (count-lines display-line-numbers-first-line (point)))
(let ((max (+ line-number nlines)))
(setq display-line-numbers-format-string (cond ((< max 100) "%2d ")
((< max 1000) "%3d ")
((< max 10000) "%4d ")
(t "%7d "))))))
(save-excursion
(condition-case nil
(progn
(goto-char display-line-numbers-first-line)
(setq buffer-file-name nil)
(setq displaying-line-numbers-p t)
(while (<= display-line-numbers-count nlines)
(insert-before-markers
(format display-line-numbers-format-string line-number))
(setq line-number (1+ line-number))
(setq display-line-numbers-count (1+ display-line-numbers-count))
(forward-line 1))
(when arg
(set-window-start (selected-window) display-line-numbers-first-line))
(goto-char point)
(set-buffer-modified-p display-line-numbers-modified-p))
(error
(progn
(goto-char display-line-numbers-first-line)
(let ((n (1+ (- (aref display-line-numbers-format-string 1) ?0))))
(while (> display-line-numbers-count 0)
(setq display-line-numbers-count (1- display-line-numbers-count))
(delete-char n)
(forward-line 1)))
(setq buffer-file-name display-line-numbers-buffer-name)
(set-buffer-modified-p display-line-numbers-modified-p)
(setq displaying-line-numbers-p nil))))))
(let ((curr-line (count-lines (window-start) (point))))
(when (> curr-line 0) (setq curr-line (1+ curr-line)))
(recenter curr-line)))
(defun turn-off-line-numbers-display ()
"Clear displayed line numbers from left margin of current buffer."
(interactive)
(unless (eq (current-buffer) (window-buffer (selected-window)))
(error "Current buffer, `%s', is not the selected window's buffer"
(buffer-name)))
(unless displaying-line-numbers-p
(error "Not displaying line numbers in buffer `%s'" (buffer-name)))
(let ((buffer-read-only nil))
(save-excursion
(when (boundp 'display-line-numbers-buffer-name)
(setq buffer-file-name display-line-numbers-buffer-name))
(goto-char display-line-numbers-first-line)
(let ((n (1+ (- (aref display-line-numbers-format-string 1) ?0))))
(while (> display-line-numbers-count 0)
(setq display-line-numbers-count (1- display-line-numbers-count))
(delete-char n)
(forward-line 1)))
(when (boundp 'display-line-numbers-modified-p)
(set-buffer-modified-p display-line-numbers-modified-p))
(setq displaying-line-numbers-p nil))))
(provide 'line-num)