Re: etags: M-. looks for an uncompressed Emacs Lisp source file, but make install installs it gzipped

["Robert J. Chassell" <bob@rattlesnake.com>]

    Francesco Potorti wrote:
    >> When looking up a tag referring a compressed ELisp file with M-.,
    >> Emacs fails to find the correct file, as it tries to open a non-existing
    >> *uncompressed* version.

Today's GNU Emacs CVS snapshot, Thu, 2007 Apr 26  09:50 UTC
GNU Emacs 22.1.50.1 (i686-pc-linux-gnu, GTK+ Version 2.8.20)
started with

    /usr/local/src/emacs/src/emacs -Q -D

For success with compressed source files, you have to evaluate

    (auto-compression-mode t)

even when report-emacs-bug says auto-compression-mode is t,
and evaluate the defun for uncompress-while-visiting,
which is in the CVS for  emacs/lisp/obsolete/uncompress.el
and then evaluate 

    (progn (cd "/usr/local/share/emacs/22.0.92/lisp")
           (compile "etags *.el")
           (visit-tags-table "/usr/local/share/emacs/22.0.92/lisp/TAGS" nil))

for compressed sources.  I had to evaluate that last expression twice.  (My
CVS sources in /usr/local/src/emacs/ are not compressed.)

Then I had no trouble running M-.  (find-tag)  on
    grep-setup-hook


Here is the information for 

    /usr/local/src/emacs/src/emacs -Q -D

without any inclusions.  This is the same as the instance with
inclusions, that is to say, with the evaluation of the two extra
expressions, except I evaluated the expressions in *scratch* so it
reports     Major mode: Emacs-Lisp

Note, it says:       auto-compression-mode: t


    In GNU Emacs 22.1.50.1 (i686-pc-linux-gnu, GTK+ Version 2.8.20)
     of 2007-04-26 on benthic
    Windowing system distributor `The X.Org Foundation', version 11.0.70101000
    configured using `configure  '--with-type1' '--with-x-toolkit=gtk' '--prefix=/usr/local' '--with-sound=yes''

    Important settings:
      value of $LC_ALL: nil
      value of $LC_COLLATE: nil
      value of $LC_CTYPE: nil
      value of $LC_MESSAGES: nil
      value of $LC_MONETARY: nil
      value of $LC_NUMERIC: nil
      value of $LC_TIME: nil
      value of $LANG: en_US
      locale-coding-system: iso-8859-1
      default-enable-multibyte-characters: nil

    Major mode: Fundamental

    Minor modes in effect:
      mouse-wheel-mode: t
      file-name-shadow-mode: t
      unify-8859-on-encoding-mode: t
      utf-translate-cjk-mode: t
      auto-compression-mode: t
      line-number-mode: t



In detail, with an instance started with emacs -Q -D, I evaluated both

    (auto-compression-mode t)

    (defun uncompress-while-visiting ()
      "Temporary \"major mode\" used for .Z and .gz files, to uncompress them.
    It then selects a major mode from the uncompressed file name and contents."
      (if (and (not (null buffer-file-name))
               (string-match "\\.Z$" buffer-file-name))
          (set-visited-file-name
           (substring buffer-file-name 0 (match-beginning 0)))
        (if (and (not (null buffer-file-name))
                 (string-match "\\.gz$" buffer-file-name))
            (set-visited-file-name
             (substring buffer-file-name 0 (match-beginning 0)))
          (if (and (not (null buffer-file-name))
                   (string-match "\\.tgz$" buffer-file-name))
              (set-visited-file-name
               (concat (substring buffer-file-name 0 (match-beginning 0)) ".tar")))))
      (message "Uncompressing...")
      (let ((buffer-read-only nil)
            (coding-system-for-write 'no-conversion)
            (coding-system-for-read
             (car (find-operation-coding-system
                   'insert-file-contents
                   buffer-file-name t))))
        (shell-command-on-region (point-min) (point-max) uncompress-program t))
      (goto-char (point-min))
      (message "Uncompressing...done")
      (set-buffer-modified-p nil)
      (add-hook 'write-file-functions 'uncompress-backup-file nil t)
      (normal-mode))

and then

    (progn (cd "/usr/local/share/emacs/22.0.92/lisp")
           (compile "etags *.el")
           (visit-tags-table "/usr/local/share/emacs/22.0.92/lisp/TAGS" nil))

I had to evaluate that last expression twice.  

I then had no trouble running M-.  (find-tag)  on
    grep-setup-hook

(When I specified its TAGS table, I had no trouble at all using
M-.  (find-tag) with the uncompressed CVS sources.)

-- 
    Robert J. Chassell                          GnuPG Key ID: 004B4AC8
    bob@rattlesnake.com                         bob@gnu.org
    http://www.rattlesnake.com                  http://www.teak.cc