From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.bugs Subject: bug#42147: 28.0.50; pure vs side-effect-free, missing optimizations? Date: Sat, 25 Jul 2020 14:10:31 -0400 Message-ID: References: <3A9CC2A3-8307-47B2-8D80-795C0AF020E1@acm.org> <0433A879-C98D-4B1A-B85C-A15DA9289099@acm.org> <1621669100.2102667.1593639091621@mail.yahoo.com> <33C2E2C8-16A6-47A9-B3A4-8A5F43648E04@acm.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="4025"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Cc: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= , Paul Eggert , Andrea Corallo , 42147@debbugs.gnu.org To: Philipp Stephani Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sat Jul 25 20:12:10 2020 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 1jzOeX-0000uG-Hj for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 25 Jul 2020 20:12:09 +0200 Original-Received: from localhost ([::1]:33326 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jzOeW-0004AV-3h for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 25 Jul 2020 14:12:08 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54938) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jzOeQ-0004AN-Gc for bug-gnu-emacs@gnu.org; Sat, 25 Jul 2020 14:12:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:39546) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jzOeP-0002LE-Ri for bug-gnu-emacs@gnu.org; Sat, 25 Jul 2020 14:12:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1jzOeP-0007pf-Lj for bug-gnu-emacs@gnu.org; Sat, 25 Jul 2020 14:12:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Stefan Monnier Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sat, 25 Jul 2020 18:12:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 42147 X-GNU-PR-Package: emacs Original-Received: via spool by 42147-submit@debbugs.gnu.org id=B42147.159570066530043 (code B ref 42147); Sat, 25 Jul 2020 18:12:01 +0000 Original-Received: (at 42147) by debbugs.gnu.org; 25 Jul 2020 18:11:05 +0000 Original-Received: from localhost ([127.0.0.1]:51092 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jzOdV-0007oV-EI for submit@debbugs.gnu.org; Sat, 25 Jul 2020 14:11:05 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:26296) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jzOdS-0007o0-GZ for 42147@debbugs.gnu.org; Sat, 25 Jul 2020 14:11:04 -0400 Original-Received: from pmg3.iro.umontreal.ca (localhost [127.0.0.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id EA2D54407C3; Sat, 25 Jul 2020 14:10:56 -0400 (EDT) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id B2A4144073B; Sat, 25 Jul 2020 14:10:32 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1595700632; bh=oaQxZ9mWaWUH4UucRq8Nr+QKfsAR9t0kejfetfYOXmM=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=adzHZOmSsf1QYuZ5xtk+BsoVk4gV9R1kt2gi+QGGRVkRRKYWddcT0Wma7Spyf/wfZ UDRVKH81s+o2wshCGlmdO9819X2ibiG5Ob0eKpE9/b95973xIBwr6324vxRKyVIt+P F95IgeKo+GCgGaQH2l+RfQgASFSqimf+z1aTelXsSb/nexNJXN2S0jz3+iCJbhvBm3 sI0bFuMRlzsKAMZt5i9v4S0Us10DHmct8veY+6XcP9ZnTbCy5Hgdkcl/H9ASJ5YseJ 3njQaP4vP+NVaiKKIV85jxsnq4dK7mD8P06kOIYfGwlPp7RcWsepL4EDU293VZ7At/ exISwc9cUCkmQ== Original-Received: from milanesa (unknown [104.247.229.155]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 6CD581202C1; Sat, 25 Jul 2020 14:10:32 -0400 (EDT) In-Reply-To: (Philipp Stephani's message of "Sat, 25 Jul 2020 19:09:30 +0200") 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:183537 Archived-At: > and "side-effect free" is like GCC's "pure." That is, a side-effect > free function can dereference pointers stored in Lisp_Objects, but a > pure function can't. I think it's still not very satisfactory since it's written in terms of low-level operations in the C code. I think the current intention of our "pure" goes something along the lines of: the function will always return the "same" (the sense of `eql`) value (or signal the same error) when called with `eql` arguments. IOW "the function preserves `eql`ity". Stefan