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From: admin@dcs.exeter.ac.uk (System Administrator)
Newsgroups: comp.emacs
Subject: Re: <None>
Message-ID: <3813@izar.dcs.exeter.ac.uk>
Date: 3 Jun 91 12:48:17 GMT
References: <1991May30.142750.9342@bronze.ucs.indiana.edu>
Sender: news@dcs.exeter.ac.uk
Organization: Computer Science Dept. - University of Exeter. UK
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In-reply-to: ury@cosmos.huji.ac.il's message of 30 May 91 14:27:50 GMT

>>>>>  In article <1991May30.142750.9342@bronze.ucs.indiana.edu> ury segal writes:
ury> I'm a programmer. I need the line numbers 'cause the compiler give
ury> them to me to tell me where the errors are.

If it is standard C compiler error message then like other people have
said that you can use other environments that will get you the line you
want provided you compiled from emacs - typically

	M-x compile

and then using C-x ` to get emacs to place you on the line where the
error is (if you are compiling with many sourec files, this
'parse-error command will also load the files if needed.)  Try also

	M-x grep

The above features combined with M-x goto-line I get by all my
requirements for getting to a specific line but I can understand that
in some cases it would be nice if emacs did infact display line
numbers.  So here is a article I dug up that appeared looong ago.  It
is not perfect but it might help

fist put a small shell script called "peep" in your path somewhere,
peep contains

while [ 1 ]
do
 echo -n x
 sleep $1
done

Then load this...

;; display-line-numbers:  Show line-numbers for an Emacs buffer.
;; Copyright (C) 1989 Wayne Mesard
;;
;; This file is not officially part of GNU EMACS.  But it is being 
;; distributed under the terms of the GNU Emacs General Public License.
;; The copyright notice and this notice must be preserved in all copies.

;; Call M-x display-line-nums  to show 'em.
;;      M-x hide-line-nums     to make 'em go away.
;; Or bind these guys to keys in your .emacs file.

;; [N.B.  I haven't tested this rigorously.  It may be buggy.]
;; I will get around to these things eventually.  Other suggestions
;; are welcome.  Mail to Mesard@BBN.COM.   -wsm
;; To do:  [wsm060289]
;;     o Support for line numbers in multiple windows is not adequate.
;;       Things like this should be possible and fool proof:
;;
;;                          +---------------------+
;;                          | 1| GNU, which stands|
;;                          | 2|for Gnu's not Unix|
;;                          | 3|is the name for   |
;;                          | 4|the complete ...  |
;;                          +---------------------+
;;                          |20|I canna change the|
;;                          |21|laws o physics    |
;;                          |22|Cap'n!            |
;;                          +---------------------+
;;
;;     o  Ctrl-X 1 hides the line number window, but doesn't kill
;;        The line-num process.  It should.  (Have the filter function
;;        check for the case when the line num window isn't on screen.)
;;     o  Ctrl-X o should not go to the num buf.
;;     o  Similarly, The *Help* buffer should NOT be allowed to come
;;        up in the line number window!
;;     o  Some function documentation would be nice.


(defvar *win-min-width* 6)
(defvar *line-num-update* 1)
(defvar line-num-process nil)
(defvar *line-num-buf* nil)

(defun display-line-nums ()
  (interactive)
  (if (> window-min-width *win-min-width*)
	(setq window-min-width *win-min-width*))
    (split-window-horizontally *win-min-width*)
    (switch-to-buffer " Line-Numbers" t)
    (setq *line-num-buf* (current-buffer))
    (other-window 1)

    (if (not (and line-num-process
		  (eq (process-status line-num-process) 'run)))
	(progn
	  (setq line-num-process
		(start-process "line-nums" nil "peep"
			       (int-to-string *line-num-update*)))
	  (set-process-sentinel line-num-process 'line-num-sentinel)
	  (set-process-filter line-num-process 'update-when-scrolled)))
	  (process-kill-without-query line-num-process)
    )

  
(defun line-num-sentinel (ignore reason)
  (hide-line-nums)
  (message "The line number process died unexpectedly: %s." reason))


(defun hide-line-nums ()
  (interactive)
  (if (and line-num-process
	   (eq (process-status line-num-process) 'run))
      (progn
	(set-process-sentinel line-num-process nil)
	(delete-process line-num-process)))
  (let ((first-window (current-buffer))
	(first-time t))
    (while (or (not (eq first-window (current-buffer)))
	       first-time)
      (setq first-time nil)
      (if (eq *line-num-buf* (current-buffer))
	  (delete-window)
	(other-window 1)))
    ))



(defvar prev-top -99)

(defun update-when-scrolled (ignore ignore)
  "When window has been scrolled, do something."
  (save-excursion
      (move-to-window-line 0)
      (if (and (not (eq (current-buffer) *line-num-buf*))
	       (/= (point) prev-top))
	  (let* ((cur-line-num  (count-lines (point-min) (point)))
		 (i (+ cur-line-num (window-height))))
	    (setq prev-top (point))
	    (other-window -1)
	    (if (eq (current-buffer) *line-num-buf*)
		(progn 
		  (newline (goto-line i))
		  (while (> i cur-line-num)
		    (setq i (1- i))
		    (forward-line -1)
		    (if (looking-at "$")
			(progn
			  (if (< i 10)
			      (insert "  ")
			    (if (< i 100)
				(insert ?\040)))
			  (insert (int-to-string i))))
		    )
		  (move-to-window-line 0)
		  (scroll-up (- i (count-lines (point-min) (point))))
		  (move-to-window-line 0)
		  ))
	    (other-window 1))
	)))

--
Khalid Sattar                   JANET   : admin@uk.ac.ex.dcs 
Computer Science Dept.          UUCP    : admin@ex-dcs.uucp
University of Exeter            INTERNET: admin%dcs.ex.ac.uk
Exeter, UK.                     Tel     : +44 392 264062