From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Philipp Stephani Newsgroups: gmane.emacs.bugs Subject: bug#51368: 29.0.50; `cl-case' should error on incorrect use Date: Sun, 31 Oct 2021 19:53:53 +0100 Message-ID: References: <87a6iy71q1.fsf@gnus.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="1093"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 51368@debbugs.gnu.org To: Lars Ingebrigtsen Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sun Oct 31 19:55:32 2021 Return-path: Envelope-to: geb-bug-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 1mhFzP-000Ae1-4B for geb-bug-gnu-emacs@m.gmane-mx.org; Sun, 31 Oct 2021 19:55:31 +0100 Original-Received: from localhost ([::1]:44014 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mhFzN-0007zp-MV for geb-bug-gnu-emacs@m.gmane-mx.org; Sun, 31 Oct 2021 14:55:29 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:40760) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mhFyy-0007xa-Lr for bug-gnu-emacs@gnu.org; Sun, 31 Oct 2021 14:55:04 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:49807) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1mhFyw-0001w0-5t for bug-gnu-emacs@gnu.org; Sun, 31 Oct 2021 14:55:04 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1mhFyw-0000kJ-1d for bug-gnu-emacs@gnu.org; Sun, 31 Oct 2021 14:55:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Philipp Stephani Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 31 Oct 2021 18:55:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 51368 X-GNU-PR-Package: emacs Original-Received: via spool by 51368-submit@debbugs.gnu.org id=B51368.16357064512803 (code B ref 51368); Sun, 31 Oct 2021 18:55:01 +0000 Original-Received: (at 51368) by debbugs.gnu.org; 31 Oct 2021 18:54:11 +0000 Original-Received: from localhost ([127.0.0.1]:33120 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1mhFy6-0000j9-Tw for submit@debbugs.gnu.org; Sun, 31 Oct 2021 14:54:11 -0400 Original-Received: from mail-ot1-f43.google.com ([209.85.210.43]:46980) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1mhFy5-0000iw-KI for 51368@debbugs.gnu.org; Sun, 31 Oct 2021 14:54:10 -0400 Original-Received: by mail-ot1-f43.google.com with SMTP id x27-20020a9d459b000000b0055303520cc4so22221464ote.13 for <51368@debbugs.gnu.org>; Sun, 31 Oct 2021 11:54:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=9kVO8K1ANUg1/8pN5wZjmXObZ+hNrdW4ye31GTld0qQ=; b=lfGosQsY0J5XrtQnsGDj19Q/6EH4wn3gqPH22CxSPxRaKByERpuY908nw6Keg/cc7i PD2i+QK3oJOnmhKTitm1kuJkHDH5Onzwj3R/H4sYa/4USjl15Y3E8b7aqr/XWQYrTjH6 Rcmq/K0Jxo1iweeaZfEhJFVGU7rneZu5JPLEiYJpORjRje3nmyQOumF5kKpsLlWUDkWQ jMeUuu6tKcfD5tWw0eKVk040RLQrHZ6uQHmhbQJ3U3PAjevpDdzHWw8r9D2MFihtt8sF E/RtJNnH87x8P+hG5N1PRUiNFADxYKwr5+rxOiOTBSyklP/rCqBWjP4CKU/oYwNKc9kg uhXQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=9kVO8K1ANUg1/8pN5wZjmXObZ+hNrdW4ye31GTld0qQ=; b=tMlRMgKw6TzH1OlDjRzR/8CYUxPfPR/VPkAmtQXK7O2w+2LmANDutmBeQdw3I0PbsF V4U84WAQ2sItqm71O1SNsv50e8wIpKI8c22YpqwbACLOwVOQJxcdSJ3X+9HpkH2aapUw q+BpW0KMoB+yNFxFixMro8B586s2RI40iZVBA0Jyans9tpfgOdSmw4rwGMdseoCtZKq7 3MVWL5GwQ37OWGev68lX/tQKDvdmePrmOdJpyXbbET/CL1gxXwl3UccT5Ej/aEyVGquq FG5Kk1Dp5z4eRIgEJ9u51U2vKHGxgISEM/ubEVDjKe3hBjQZRE52G95n4iix2Y7NUhLa W+jg== X-Gm-Message-State: AOAM532Y5udyGN/Ogn/MueQMIckU8QGdqt8ATDEzeiQWmqM/V6YdV/uw mENOHLFaKjF+xQlEj1u1WFVZf/2ziXdz/mV7QbE= X-Google-Smtp-Source: ABdhPJyJmT5JJ18hTo9XrllZrCgyjznqOWYpxKvEFFCfdXQ6GnbFUof3OiIKh+rCYAWG/TcpSyfeLPnZV2B2RljO5OM= X-Received: by 2002:a9d:669:: with SMTP id 96mr18214145otn.224.1635706443845; Sun, 31 Oct 2021 11:54:03 -0700 (PDT) In-Reply-To: <87a6iy71q1.fsf@gnus.org> X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:218715 Archived-At: Am So., 24. Okt. 2021 um 19:48 Uhr schrieb Lars Ingebrigtsen : > > Philipp Stephani writes: > > > This form demonstrates a few incorrect uses of `cl-case': > > > > (cl-case a > > (nil 0) ; doesn't match anything > > (t 1) ; matches everything, but too early > > ('foo 2)) ; matches `quote' in addition to `foo' > > > > It would be nice if `cl-case' would signal an error or at least warn > > about these at macroexpansion time, since they are somewhat subtle and > > easy to get wrong. > > An error from the second case would be nice, and a warning on the first > case, but the third case: > > (macroexpand > '(cl-case a > ('foo (message "foo")))) > => (cond ((cl-member a ''foo) (message "foo"))) > > and > > (equal ''foo (list 'quote 'foo)) > > which, sure, whatever. But I guess the question is whether we can > actually warn about that, because to the reader, the two forms are > equivalent? Yes, but the problem only arises if the user wants to match the symbol `quote' plus exactly one other value. That should already be exceedingly rare, and can be trivially rewritten by swapping the two values (i.e. write (foo quote) instead of (quote foo)). So I think issuing a warning or error for that case is worth it. Assuming we'd want to prevent similar bugs with other reader constructs, I think the only real problematic case is matching exactly two of the symbols `function', `quote', `,', `,@', and `\`'. Maybe for those cases we should just instruct people to write (cond (memq ...)) or similar.