best practices for TAGS

best practices for TAGS

[Xavier Noria]

I would basically like to have a workflow for the TAGS file that makes
some assumptions, and thanks to them it works out of the box and it is
always in sync.

For example, define the current tags file as the first one you find
from the current directory up the hierarchy, nil if none found.

I'd like to define my own version of find-tag that looks for the
current tags file as defined above.

If the tags file is outdated, I'd like to run some shell command
automatically and revisit it, then do the find-tag.

No prompts whatsoever. If I find myself in a situation where the
conventions do not hold, I'll resort to the builtin functions.

You see, I'd like that find-tag and friends do automatically what
makes sense in 99% of my projects and be always in sync without my
intervention.

Does anybody work use a worflow like that?

Re: best practices for TAGS

[Xavier Noria]

On Mon, Dec 5, 2011 at 12:29 AM, Xavier Noria <fxn@hashref.com> wrote:

> If the tags file is outdated, I'd like to run some shell command
> automatically and revisit it, then do the find-tag.

Easier: regenerate and revisit always. Every invocation of find-tag
should do that.

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 If the tags file is outdated, I'd like to run some shell command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

Re: best practices for TAGS

[Bastian Beischer]

I use etags-table which assigns TAGS files to my projects and GNU Make
rules to update the TAGS file when I run make... The suggested
algorithms to update it always might work better, though.

On Mon, Dec 5, 2011 at 12:29 AM, Xavier Noria <fxn@hashref.com> wrote:
> I would basically like to have a workflow for the TAGS file that makes
> some assumptions, and thanks to them it works out of the box and it is
> always in sync.
>
> For example, define the current tags file as the first one you find
> from the current directory up the hierarchy, nil if none found.
>
> I'd like to define my own version of find-tag that looks for the
> current tags file as defined above.
>
> If the tags file is outdated, I'd like to run some shell command
> automatically and revisit it, then do the find-tag.
>
> No prompts whatsoever. If I find myself in a situation where the
> conventions do not hold, I'll resort to the builtin functions.
>
> You see, I'd like that find-tag and friends do automatically what
> makes sense in 99% of my projects and be always in sync without my
> intervention.
>
> Does anybody work use a worflow like that?
>



-- 
Bastian Beischer

I. Physikalisches Institut B (RWTH Aachen)
Sommerfeldstr. 14
52074 Aachen
GERMANY

Office: 28-C-203
Phone: +49 241 - 8027205

Re: best practices for TAGS

[Philipp Haselwarter]

I'd make a buffer local variable for the tags file name on your
`cc-mode-hook' or something suitable, using for example

(let ((dir (locate-dominating-file default-directory "TAGS")))
  (if dir
      (set (make-local-variable 'my-local-tags-fn)
        (expand-file-name "TAGS" dir))
    (message "TAGS not found")))

then call etags on your after-save-hook if the variable is set

(if (bound-and-true-p my-buffer-local-tags-filename)
 (start-process "regen-TAGS" nil "etags.emacs" "-o" my-buffer-local-tags-filename "-a"
  (buffer-file-name)))

-- 
Philipp Haselwarter