Path: utzoo!utgpu!attcan!uunet!yale!Ram-Ashwin
From: Ram-Ashwin@cs.yale.edu (Ashwin Ram)
Newsgroups: comp.emacs
Subject: Re: How to find 'defuns' in GNU Emacs source
Message-ID: <34466@yale-celray.yale.UUCP>
Date: 29 Jul 88 15:14:51 GMT
References: <638@novavax.UUCP> <27626@bbn.COM>
Sender: root@yale.UUCP
Reply-To: Ram-Ashwin@cs.yale.edu (Ashwin Ram)
Organization: Computer Science, Yale University, New Haven, CT 06520-2158
Lines: 36
In-reply-to: mesard@bbn.com (Wayne Mesard)

In article <27626@bbn.COM>, mesard@bbn (Wayne Mesard) writes:
> It does tag searches on Emacs source while preserving the current tags
> environment.  (So you can interleave tags searches on GNU code and your
> own code.)
>
> (defun find-emacs-tag (emacs-tagname &optional next other-window)
>   (interactive ...)
>   (let ((old-tags-file-name tags-file-name)
> 	(old-last-tag last-tag))
>     (setq tags-file-name "/usr/local/emacs/lisp/TAGS"
> 	  last-tag last-emacs-tag)
>     (unwind-protect
> 	(find-tag emacs-tagname next other-window)
>       (setq last-emacs-tag last-tag
> 	    last-tag old-last-tag
> 	    tags-file-name old-tags-file-name)
>       )
> ))

I like the idea; I use something similar myself but I hadn't thought of the
last-tag idea.  However, to improve on this code, one could do:

        (interactive ...)
        (let ((tags-file-name "/usr/local/emacs/lisp/TAGS")
              (last-tag last-emacs-tag))
           (find-tag emacs-tagname next other-window)
           (setq last-emacs-tag last-tag))

This is a lot simpler, doesn't require the old-* variables, and will do the same
thing.  There is no need to do the setq's explicitly since that's part of LET's job.

-- Ashwin.

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