Re: Convenient way to set "root of my project"?

[Andreas Politz <politza@fh-trier.de>]

Brett Hoerner wrote:
> I'd like for commands like "grep" and "find file" to open at the root
> of my "project" (I know emacs has no knowledge of projects).  Does
> anyone do / use something similar?
> 
> For example, I'm in /foo/bar/blah/doo/woo/file and I M-x grep, it's
> based in /foo/bar/blah/doo/woo/ and I don't want to take the time to
> change the path every time - 99% of the time I want to search my
> current project (let's say /foo) for something.  Ditto for find-file,
> changes are the file I want isn't in /foo/bar/blah/doo/woo/, but
> somewhere further up the tree (and down another branch), I'd love to
> start at /foo.
> 
> Ideas?  Or maybe I'm using both of these wrong and someone can tell me
> the proper emacs-foo?
> 
> Thanks,
> Brett


Here is some code to play around with. The problem I thinks is,
there is no hook into the post process of M-x commands. By
the time you know which command is running, it is to late to
set up a directory.
The solution I've made is to rebind M-x and artifically trigger
post/pre-command-hooks. I don't know exactly what sideeffects
this has, but I also don't see any other convenient solution.
(For the problem of setting up a special directory for certain
commands, regardless of how (M-x or keys) they where invoked.)

-ap

------------%<---------------------
(defvar project-directory-commands-hash nil)
(defvar project-directory-temp nil)
(make-variable-buffer-local 'project-directory-temp)

(defvar project-directory-commands '(rgrep))

(define-minor-mode project-directory-commands-mode
   "Use `project-directory' instead of `default-directory' for
certain commands"
   nil nil nil
   :global t
   (cond
    (project-directory-commands-mode
     (add-hook 'pre-command-hook 'project-directory-pre-command)
     (add-hook 'post-command-hook 'project-directory-post-command)
     (setq project-directory-commands-hash (make-hash-table))
     (global-set-key (kbd "M-x") 'extended-execute-extended-command)
     (dolist (c project-directory-commands)
       (puthash c t project-directory-commands-hash)))

    (t
     (global-set-key (kbd "M-x") 'execute-extended-command)
     (remove-hook 'pre-command-hook 'project-directory-pre-command)
     (remove-hook 'post-command-hook 'project-directory-post-command)
     (clrhash project-directory-commands-hash))))

(defun project-directory-pre-command ()
   (when (and (gethash this-command project-directory-commands-hash)
              (boundp 'project-directory)
              project-directory)
     (setq project-directory-temp default-directory)
     (setq default-directory project-directory)))

(defun project-directory-post-command ()
   (when project-directory-temp
     (setq default-directory project-directory-temp)
     (setq project-directory-temp nil)))



(defun extended-execute-extended-command (command)
   (interactive (list
                 (intern
                  (completing-read
                   (concat
                    (cond
                     ((eq '- current-prefix-arg) "- ")
                     ((equal current-prefix-arg '(4)) "C-u ")
                     (current-prefix-arg (format "%d " (prefix-numeric-value current-prefix-arg))))
                    "M-x ")
                   obarray 'commandp t nil 'extended-command-history))))
   (let ((this-command command))
     (run-hooks 'pre-command-hook))
   (condition-case nil
       (command-execute command)
     (error nil))
   (let ((this-command command))
     (run-hooks 'post-command-hook)))


;;(set (make-local-variable 'project-directory) "/")
(provide 'project-directory-commands)
------------%<---------------------