Re: Overlay arrow in *compilation* and *grep* buffers

[Nick Roberts]

 >     SM> I recently realized that while the 0-context sometimes makes sense
 >     for SM> C-x `, the "don't move" behavior would be preferable when
 >     getting SM> to an error by using RET or mouse-2 on the actual error
 >     text.
 > 
 > That is true *if* we use the overlay arrow.  However, as has just been
 > pointed out, using the overlay arrow in error message lists is very
 > annoying on text consoles.  On text consoles, I think it would be
 > better to move to the top, even for RET or Mouse-2, than to display
 > the overlay arrow.

This patch does what you are suggesting. It doesn't do what Stefan suggested
(not because I don't think it is a good idea, but because I don't know how to
implement it cleanly). It might be better to change the condition for a text
terminal to one that checks for a left-hand fringe, if thats possible.


Nick


*** /home/nick/emacs/lisp/progmodes/compile.el.~1.352.~ 2005-04-24 
07:39:26.000000000 +1200
--- /home/nick/emacs/lisp/progmodes/compile.el  2005-04-30 00:15:11.000000000 
+1200
***************
*** 1247,1253 ****
    (make-local-variable 'compilation-messages-start)
    (make-local-variable 'compilation-error-screen-columns)
    (make-local-variable 'overlay-arrow-position)
!   (set (make-local-variable 'overlay-arrow-string) "=>")
    (setq next-error-overlay-arrow-position nil)
    (add-hook 'kill-buffer-hook
            (lambda () (setq next-error-overlay-arrow-position nil)) nil t)
--- 1247,1253 ----
    (make-local-variable 'compilation-messages-start)
    (make-local-variable 'compilation-error-screen-columns)
    (make-local-variable 'overlay-arrow-position)
!   (set (make-local-variable 'overlay-arrow-string) "")
    (setq next-error-overlay-arrow-position nil)
    (add-hook 'kill-buffer-hook
            (lambda () (setq next-error-overlay-arrow-position nil)) nil t)
***************
*** 1576,1593 ****
  
  (defcustom compilation-context-lines 0
    "*Display this many lines of leading context before message.
! If nil, don't scroll the compilation output window."
    :type '(choice integer (const :tag "No window scrolling" nil))
    :group 'compilation
    :version "22.1")
  
  (defsubst compilation-set-window (w mk)
    "Align the compilation output window W with marker MK near top."
!   (if (integerp compilation-context-lines)
!       (set-window-start w (save-excursion
!                             (goto-char mk)
!                             (beginning-of-line (- 1 
compilation-context-lines))
!                             (point))))
    (set-window-point w mk))
  
  (defvar next-error-highlight-timer)
--- 1576,1599 ----
  
  (defcustom compilation-context-lines 0
    "*Display this many lines of leading context before message.
! If nil, don't scroll the compilation output window. Text terminals never
! scroll because no overlay arrow is present."
    :type '(choice integer (const :tag "No window scrolling" nil))
    :group 'compilation
    :version "22.1")
  
  (defsubst compilation-set-window (w mk)
    "Align the compilation output window W with marker MK near top."
!   (if (display-graphic-p)
!       (if (integerp compilation-context-lines)
!         (set-window-start w (save-excursion
!                               (goto-char mk)
!                               (beginning-of-line (- 1 
compilation-context-lines))
!                               (point))))
!     (set-window-start w (save-excursion
!                         (goto-char mk)
!                         (beginning-of-line 1)
!                         (point))))
    (set-window-point w mk))
  
  (defvar next-error-highlight-timer)