From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.help Subject: Re: How to test for native JSON support? Date: Tue, 04 May 2021 15:50:23 +0300 Message-ID: <834kfi64ts.fsf@gnu.org> References: <87k0ohuybx.fsf@fastmail.fm> <785b4132-da32-0da8-519d-b39a58270f32@gmail.com> <87y2cuybeu.fsf@passepartout.tim-landscheidt.de> <838s4u66f0.fsf@gnu.org> <87fsz2n075.fsf@fastmail.fm> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="8689"; mail-complaints-to="usenet@ciao.gmane.io" To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Tue May 04 14:51:10 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 1lduW6-00026c-5B for geh-help-gnu-emacs@m.gmane-mx.org; Tue, 04 May 2021 14:51:10 +0200 Original-Received: from localhost ([::1]:59614 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lduW5-0007EN-7p for geh-help-gnu-emacs@m.gmane-mx.org; Tue, 04 May 2021 08:51:09 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:34018) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lduVZ-0007E4-TN for help-gnu-emacs@gnu.org; Tue, 04 May 2021 08:50:37 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:50946) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lduVZ-00042Z-LY for help-gnu-emacs@gnu.org; Tue, 04 May 2021 08:50:37 -0400 Original-Received: from 84.94.185.95.cable.012.net.il ([84.94.185.95]:4487 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1lduVY-0000VG-7G for help-gnu-emacs@gnu.org; Tue, 04 May 2021 08:50:36 -0400 In-Reply-To: <87fsz2n075.fsf@fastmail.fm> (message from Joost Kremers on Tue, 04 May 2021 14:29:53 +0200) 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:129421 Archived-At: > From: Joost Kremers > Cc: help-gnu-emacs@gnu.org > Date: Tue, 04 May 2021 14:29:53 +0200 > > > It actually displays an error message, in addition to returning nil > > (as do all other JSON primitives in that case). > > So should I wrap my call to `(json-serialize '((test . 1)))` in `ignore-errors` It doesn't signal an error, just displays a message. So it effectively already does ignore-errors. > if I don't want to worry unsuspecting users with a (possibly to them arcane) > error message? (Unfortunately, I don't have access to a Windows machine so I > can't test this myself.) The message is "jansson library not found". But to answer your question, you should allow the user to determine whether the built-in or the Lisp implementation will be used, because only the user knows whether the library is installed. > And is there a reason why the native json-functions do not gracefully degrade to > their counterparts in the `json.el` library? First, because no one wrote the code to do that; patches welcome. Second, because the implementations are not 100% equivalent, neither in the API names nor in some aspects of the functionality. So automatic replacement is not trivial, not in general anyway.