From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Michael Heerdegen via "Emacs development discussions." Newsgroups: gmane.emacs.devel Subject: Re: pcase generates an unprintable expansion for a form in test erc--restore-initialize-priors Date: Sun, 26 May 2024 23:19:16 +0200 Message-ID: <87ed9oe0ff.fsf@web.de> References: Reply-To: Michael Heerdegen Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="4260"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: emacs-devel@gnu.org Cancel-Lock: sha1:1dNbraaDPB5TcS3B7c32J9N7P1o= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sun May 26 23:19:36 2024 Return-path: Envelope-to: ged-emacs-devel@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 1sBLHE-0000t8-42 for ged-emacs-devel@m.gmane-mx.org; Sun, 26 May 2024 23:19:36 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sBLGO-0004Ud-1r; Sun, 26 May 2024 17:18:44 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sBLGN-0004UM-5i for emacs-devel@gnu.org; Sun, 26 May 2024 17:18:43 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sBLGL-00011t-DV for emacs-devel@gnu.org; Sun, 26 May 2024 17:18:42 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1sBLGJ-000ADO-4Y for emacs-devel@gnu.org; Sun, 26 May 2024 23:18:39 +0200 X-Injected-Via-Gmane: http://gmane.org/ Received-SPF: pass client-ip=116.202.254.214; envelope-from=ged-emacs-devel@m.gmane-mx.org; helo=ciao.gmane.io 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, FREEMAIL_FORGED_FROMDOMAIN=0.001, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:319593 Archived-At: Alan Mackenzie writes: > The form being compared using pcase, although not tiny, is not all that > big, and it would be easy to increase its size to cause it to violate any > reasonable value of PRINT_CIRCLE. Even worse: if you try to compile a file consisting of only this defun (this is exactly one part of that test factored out): #+begin_src emacs-lisp (defun erc--restore-initialize-priors-1 (expansion) (pcase expansion (`(let* ((,p (or erc--server-reconnecting erc--target-priors)) (,q (and ,p (alist-get 'erc-my-mode ,p)))) (unless (local-variable-if-set-p 'erc-my-mode) (error "Not a local minor mode var: %s" 'erc-my-mode)) (setq foo (if ,q (alist-get 'foo ,p) (ignore 1 2 3)) bar (if ,q (alist-get 'bar ,p) #'spam) baz (if ,q (alist-get 'baz ,p) nil))) t))) #+end_src with a slightly reduced `max-lisp-eval-depth' (from 1600 to 1000) compilation fails. > Would it be possible and a good idea to amend pcase such that it > generates less deeply nested expansions for forms such as we have here? I think this todo in pcase.el is related: ;; - try and be more clever to reduce the size of the decision tree, and ;; to reduce the number of leaves that need to be turned into functions: > Or does anybody have any ideas how better to resolve the problem? Apart from trying to work around it somehow, I don't. Michael.