Re: best practices for TAGS

[Peter Münster]

On Mon, Dec 05 2011, Xavier Noria wrote:

> For example, define the current tags file as the first one you find
> from the current directory up the hierarchy, nil if none found.
>
> If the tags file is outdated, I'd like to run some shell command
> automatically and revisit it, then do the find-tag.

--8<---------------cut here---------------start------------->8---
(defun pm/find-tags-file ()
  "Recursively searches each parent directory for a file named `TAGS'
   and returns the path to that file or nil if a tags file is not found.
   Returns nil if the buffer is not visiting a file.
   (from jds-find-tags-file in the emacs-wiki)"
  (labels ((find-tags-file-r
            (path)
            (let* ((parent (if path (file-name-directory path)
                             default-directory))
                   (possible-tags-file (concat parent "TAGS")))
              (cond
               ((file-exists-p possible-tags-file)
                (shell-command (concat "make -C" parent " TAGS"))
                (throw 'found-it possible-tags-file))
               ((string= "/TAGS" possible-tags-file)
                (error "no tags file found"))
               (t
                (find-tags-file-r (directory-file-name parent)))))))
    (catch 'found-it 
      (find-tags-file-r (buffer-file-name)))))

(defadvice find-tag (before pm/before-find-tag activate)
  (setq tags-file-name (pm/find-tags-file)))
--8<---------------cut here---------------end--------------->8---

-- 
           Peter