From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Jean Louis Newsgroups: gmane.emacs.help Subject: Re: Better way to make sure external command exists in the system? Date: Sun, 21 Mar 2021 17:07:18 +0300 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="13918"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mutt/2.0.6 (2021-03-06) Cc: Help GNU Emacs To: Daniel =?utf-8?Q?Mart=C3=ADn?= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sun Mar 21 15:08:55 2021 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lNylC-0003WU-S0 for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 21 Mar 2021 15:08:54 +0100 Original-Received: from localhost ([::1]:36082 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lNylB-0001H2-RZ for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 21 Mar 2021 10:08:53 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:56298) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lNyk5-0001GL-Kp for help-gnu-emacs@gnu.org; Sun, 21 Mar 2021 10:07:47 -0400 Original-Received: from stw1.rcdrun.com ([217.170.207.13]:51107) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lNyk2-0002Nc-HO for help-gnu-emacs@gnu.org; Sun, 21 Mar 2021 10:07:45 -0400 Original-Received: from localhost ([::ffff:41.202.241.53]) (AUTH: PLAIN securesender, TLS: TLS1.3,256bits,ECDHE_RSA_AES_256_GCM_SHA384) by stw1.rcdrun.com with ESMTPSA id 000000000001E082.000000006057532B.0000561D; Sun, 21 Mar 2021 07:07:39 -0700 Mail-Followup-To: Daniel =?utf-8?Q?Mart=C3=ADn?= , Help GNU Emacs Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=217.170.207.13; envelope-from=bugs@gnu.support; helo=stw1.rcdrun.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.io gmane.emacs.help:128473 Archived-At: * Daniel Martín [2021-03-19 16:59]: > > - before variables get defined, I would use `executable-find' but I > > would like for the program loading to fail if those external > > programs cannot be found. > > Why do you think that checking for the existence of programs on load is > better? I think it would slow down loading the module, and the benefits > are not clear to me. For example, the Elisp module may still be useful > even if it cannot call external programs. > > Why is it better than simply calling `executable-find' when invoking a > command that depends on an external program? I would not like later invoking functions that don't work. But I do the checks in the functions. Sometimes majority of functions belong in the same domain that uses external commands. (defun rcd-which-list (command-list) "Verifies that list of shell commands COMMAND-LIST exist in user's $PATH" (let ((all-exist t)) (dolist (command command-list all-exist) (unless (executable-find command) (setq all-exist nil) (rcd-warning-message "Shell command `%s' does not exist" command))))) (defun optimize-image-jpg (file) "Optimizes the JPG image with quality 70%" (if (rcd-which-list '("mogrify")) (let ((extension (file-name-extension file))) (when (equal (downcase extension) "jpg") (let* ((file (shell-double-quote file)) (command (format "mogrify -sampling-factor 4:2:0 -strip -interlace JPEG -colorspace RGB -quality 70 \"%s\"" file))) (message command) (shell-command command)))) (rcd-warning-message "RCD ERROR: `mogrify' not found in $PATH"))) (defun optimize-jpg-images-dired () "Optimizes JPG images inside of Dired" (interactive) (let ((files (dired-get-marked-files))) (dolist (file files) (optimize-image-jpg file)) (revert-buffer))) (defun image-resize (file &optional size) "Resizes the JPG image with default size" (if (rcd-which-list '("mogrify")) (let ((extension (file-name-extension file))) (when (or (equal (downcase extension) "jpg") (equal (downcase extension) "png")) (let* ((file (shell-double-quote file)) (command (format "mogrify -resize %s \"%s\"" size file))) (message command) (call-process-shell-command command)))) (rcd-warning-message "RCD ERROR: `mogrify' not found in `$PATH'"))) (defun image-resize-dired () "Resizes images" (interactive) (let ((files (dired-get-marked-files)) (size (read-number "Size: " *image-default-resize-size* '(*image-resize-sizes*)))) (dolist (file files) (image-resize file size)) (revert-buffer))) (defun rcd-play-sound-bg (file) "Plays found file in background" (let ((play (executable-find "play"))) (if play (let ((command (format "play \"%s\"" file))) (async-shell-command command)) (message "RCD ERROR: `play' not found in $PATH")))) (defun rcd-warning-message (format-string &rest message) "Plays a warning sound while using function `message' as usual." (rcd-play-sound-bg rcd-warning-message-sound-file) (apply 'message format-string message))