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In emacs you use the function “occur” to find all occurrences of a string (or regexp) in a buffer. The matching lines are listed in another buffer named “*Occur*”, and you can click them there to navigate to the corresponding lines in the original buffer. That is, buffer ‘*Occur*’ acts as a hypertext index to your buffer.

Here’s a little bit of elisp that I wrote inside the dot emacs (the configuration to customize stuff) to re-define occur (well it’s actually a sort of wrapper of the function since itself isn’t touched and you can still call it with M-x occur ).

As the code is already commented, I’ll put it here without much explanation.

(defun my-occur (&optional arg)
 "Make sure to always put occur in a vertical split, into a narrower buffer at the side.
I didn't like the default horizontal split, nor the way it messes up the arrangement of windows in the frame or 
the way in which the standard way uses a neighbor window."
  (interactive "P")
  (window-configuration-to-register ?y) ; store whatever frame configuratin we are currently in
  (occur (read-from-minibuffer "Regexp: "))
  (if (occur-check-existence)
        (enlarge-window-horizontally -10)
        (set-cursor-color "green")))

(defun occur-procede-accordingly ()
  "Switch to occur buffer or prevent opening of the occur window if no matches occured."
  (interactive "P")
  (if (not(get-buffer "*Occur*"))
      (message "There are no results.")
    (switch-to-buffer "*Occur*")))

(defun occur-check-existence()
  "Signal the existance of an occur buffer depending on the number of matches."
  (if (not(get-buffer "*Occur*"))

(define-key global-map (kbd "C-S-o") 'my-occur)

(defun occur-mode-quit ()
  "Quit and close occur window. I want to press 'q' and leave things as they were before in regard of the split of windows in the frame.
This is the equivalent of pressing C-x 0 and reset windows in the frame, in whatever way they were,
plus jumping to the latest position of the cursor which might have been changed by using the links out
of any of the matches found in occur."
  (switch-to-buffer "*Occur*")
  ;; in order to know where we put the cursor thay might have jumped from qoccur
  (other-window 1)                  ;; go to the main window
  (point-to-register ?1)            ;; store the latest cursor position
  (switch-to-buffer "*Occur*")      ;; go back to the occur window
  (kill-buffer "*Occur*")           ;; delete it
  (jump-to-register ?y)             ;; reset the original frame state
  (set-cursor-color "rgb:ff/fb/53") ;; reset cursor color
  (register-to-point ?1))           ;; re-position cursor

;; some key bindings defined below. Use "p" ans "n" as in dired mode (without Cntrl key) for previous and next line; just show occurrence without leaving the "occur" buffer; use RET to display the line of the given occurrence, instead of jumping to i,t which you do clicking instead;  also quit mode with Ctrl-g.
(define-key occur-mode-map (kbd "q") 'occur-mode-quit)
(define-key occur-mode-map (kbd "C-q") 'occur-mode-quit)
(define-key occur-mode-map (kbd "C-g") 'occur-mode-quit)
(define-key occur-mode-map (kbd "C-RET") 'occur-mode-goto-occurrence-other-window)
(define-key occur-mode-map (kbd "C-<up>") 'occur-mode-goto-occurrence-other-window)
(define-key occur-mode-map (kbd "RET") 'occur-mode-display-occurrence)
(define-key occur-mode-map (kbd "p") 'previous-line)
(define-key occur-mode-map (kbd "n") 'next-line)


2 Trackbacks/Pingbacks

  1. […] Here there is a mention of the fantastic occur command. […]

  2. By links for 2009-06-16 - Qbi's Weblog on 17 Jun 2009 at 4:04 am

    […] and modify the raw traffic passing in both directions. (tags: security debug proxy ssl https http) customizing emacs occur In emacs you use the function “occur” to find all occurrences of a string (or regexp) in a […]

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