Re: Don't concat directories to file names

["Juanma Barranquero" <lekktu@gmail.com>]

On 6/15/07, Stephen J. Turnbull <stephen@xemacs.org> wrote:

> XEmacs doesn't enforce it (we can't without imposing a gratuitous
> incompatibility, since until now Emacs hasn't really had the concept),

Aha.

> but the variable `user-init-directory' is available to any library
> that wants an Emacs-specific place to put things.  This is normally
> initialized to "~/.xemacs" by startup.el.

Then the recently introduced `user-emacs-directory' should be renamed
to `user-init-directory', or aliased, I think (but it doesn't make
much sense to alias a just created var). The variable currently must
end with a directory separator, but that could be fixed.

But all in all, what I'm interested is having a public function so
modules that currently do

  (defvar my-module-setup-file "~/.my-module-data")

or

  (defvar my-module-setup-file
   (cond ((file-exists-p "~/.my-module-data") "~/.my-module-data")
         ((file-directory-p "~/.emacs.d/" "~/.emacs.d/my-module-setup"))
         (t ...)))

can be easily transformed to

  (defvar my-module-setup-file
   (user-emacs-file "my-module-data"  ; back-compatible
                    "my-module-setup" ; optional, default to above
                    ))

i.e. (it's a reworked version):

(defun user-emacs-file (name &optional new-name)
  "Convert NAME to an absolute per-user Emacs-specific path.
If \"~/NAME\" exists, or `user-emacs-directory' is nil, return \"~/NAME\".
Else, return \"`user-emacs-directory'/NEW-NAME\", or /NAME if NEW-NAME is nil."
  (convert-standard-filename
   (let ((at-home (expand-file-name name (concat "~" init-file-user))))
     (if (or (file-readable-p at-home)
             (null user-emacs-directory))
         at-home
       (or (file-accessible-directory-p (directory-file-name
user-emacs-directory))
           (progn (make-directory user-emacs-directory) t)  ;; don't
catch errors
           (expand-file-name (or new-name name) user-emacs-directory))))))

That function makes use of `user-emacs-directory' (that'd be
`user-init-directory', in XEmacs); uses `convert-standard-filename'
and, as requested, creates the ~/.emacs.d (~/.xemacs) directory on the
fly.

People wanting to use the same setup files in X?Emacs will have to
make user-(emacs|init)-directory point to the right place, or perhaps
set it to nil (and then `user-emacs-file' defers to ~/ and does not
try to create any dir).

WDYT?

             Juanma