From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Naoya Yamashita Newsgroups: gmane.emacs.devel Subject: [PATCH] * src/eval.c: Stop checking for nvars, and use only CONSP Date: Tue, 02 Mar 2021 11:10:43 +0900 (JST) Message-ID: <20210302.111043.609653289571449353.conao3@gmail.com> Mime-Version: 1.0 Content-Type: Multipart/Mixed; boundary="--Next_Part(Tue_Mar__2_11_10_43_2021_296)--" Content-Transfer-Encoding: 7bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="20487"; mail-complaints-to="usenet@ciao.gmane.io" To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue Mar 02 03:18:26 2021 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 1lGucE-0005FP-OH for ged-emacs-devel@m.gmane-mx.org; Tue, 02 Mar 2021 03:18:26 +0100 Original-Received: from localhost ([::1]:34708 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lGucD-0001z2-O9 for ged-emacs-devel@m.gmane-mx.org; Mon, 01 Mar 2021 21:18:25 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:45102) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lGuW1-0006DF-BS for emacs-devel@gnu.org; Mon, 01 Mar 2021 21:12:01 -0500 Original-Received: from mail-pj1-x102f.google.com ([2607:f8b0:4864:20::102f]:37744) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lGuVz-0005hg-7I for emacs-devel@gnu.org; Mon, 01 Mar 2021 21:12:00 -0500 Original-Received: by mail-pj1-x102f.google.com with SMTP id u12so889144pjr.2 for ; Mon, 01 Mar 2021 18:11:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:message-id:to:subject:from:mime-version :content-transfer-encoding; bh=3G9rchLOCH/e3Id1cwQEFYPBS8kaDJLPhXNwtS61dOI=; b=FDu73s0Lc6JvDonywnPx4iAFFIeAC3isuCFOiLx+VeOqdYy5rlIvq1E8hirMuiRN1v cPl0ve59Bia0ugaXR40mf2waGkM2Vziap5HljuQ5FVMDpKkBBljxMHxY40GTbD9FjFSf aZMrS/dAgwKk7M4F2RrGPQwtwUj/KNPUDMMMBX1kBW/akLrI6NkHb0rOt4F0Oc8FHgR4 8MYfjURkMyTfyT7sjGEyk8AjHcq/PoV5jtPjp7gvpa6vbFz5XHUmoDKuxSniuA9O3LqQ cTBVwExkdIgr9/he+ELsmkOQQLA6wVDkyc6wTQsgYNZ2lCbvDlv3TuaQiB6e8y7eeErv dUJg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:to:subject:from:mime-version :content-transfer-encoding; bh=3G9rchLOCH/e3Id1cwQEFYPBS8kaDJLPhXNwtS61dOI=; b=BdRZCivAKYOfMgcjK8zHFJH+xrZr4aTVUHvoqDcAb+Zhj0oIobrzCe1P+VxYrob7Ao uBogg/7Q6D+jDL396guADsWtnqNCYK0dCNZx2IiRKtoxKQVfhSpU24j7yyNAB0DZfXrt M5mMf/3rkDMvCMoI9IjdAJI2LfOXa8TBgAQgzQRcnlD+e5GYlhkPlIQUBrdJO33Qb4Vu rmoXAMIkrfYz8fTBw5Rf0nVEFTtUn+NGYHBcPcnGfHn/HyaFIiWOYCNgJOLeEMW4BvMO WCfHvoZOg8C/ph+PVubT7PqHHsiXd/f1mUuX4C10whh1v3edF/2vR9KlqPnYxXIfGSI1 nskw== X-Gm-Message-State: AOAM533rt9ti5LzKrk7tpGqHdzb9j1a9JJAw1WY3Sivq8dvCT6ia2SPj QKw+GRJPVV03gupOKQg1PzzbZFcgMiVkMQ== X-Google-Smtp-Source: ABdhPJy1YKLsR1+oFd1hu82nYPC4XMVGtAHQJup9qdqcfBRCXnfxs3fzkktNTApfjiXVWUJ8jjbW5Q== X-Received: by 2002:a17:90a:ab09:: with SMTP id m9mr2027020pjq.122.1614651114792; Mon, 01 Mar 2021 18:11:54 -0800 (PST) Original-Received: from localhost (p210141-ipngn200407niho.hiroshima.ocn.ne.jp. [118.4.79.141]) by smtp.gmail.com with ESMTPSA id f3sm18410527pfe.25.2021.03.01.18.11.53 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Mar 2021 18:11:54 -0800 (PST) X-Mailer: Mew version 6.8 on Emacs 27.1 Received-SPF: pass client-ip=2607:f8b0:4864:20::102f; envelope-from=conao3@gmail.com; helo=mail-pj1-x102f.google.com X-Spam_score_int: -17 X-Spam_score: -1.8 X-Spam_bar: - X-Spam_report: (-1.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 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" Xref: news.gmane.io gmane.emacs.devel:265796 Archived-At: ----Next_Part(Tue_Mar__2_11_10_43_2021_296)-- Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hi! I found src/eval.c (let) has redundant conditions, that compares the length of the list with the current index and also checks if the current list is cons. I remove latter check, and it compiled fine and passed all the tests I added. However, in such cases, Lisper prefers to compare that the current list is cons, rather than comparing indices. Taking a `cdr` and checking that it is cons is a Lisp idiom in situations where `mapc` and `dolist` are not available. The concern is it may be faster to check the index than CONSP. This would be fast enough because CONSP in C is a macro, which is eventually converted to a bitwise operation. The code is considered to be easier to read and less prone to bugs than the current code that includes variable reuse and reassignment. Regards, Naoya. ----Next_Part(Tue_Mar__2_11_10_43_2021_296)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="0001-src-eval.c-Stop-checking-for-nvars-and-use-only-CONS.patch" >From 622c96bdb41bda2727242f8a8078bb8114ef667f Mon Sep 17 00:00:00 2001 From: Naoya Yamashita Date: Tue, 2 Mar 2021 10:17:29 +0900 Subject: [PATCH] * src/eval.c: Stop checking for nvars, and use only CONSP * src/eval.c (let): Remove checking nvars (length of arglist), and use only CONSP check. --- src/eval.c | 6 ++---- test/src/eval-tests.el | 27 +++++++++++++++++++++++++++ 2 files changed, 29 insertions(+), 4 deletions(-) diff --git a/src/eval.c b/src/eval.c index 542d7f686e..30783f204a 100644 --- a/src/eval.c +++ b/src/eval.c @@ -1001,11 +1001,10 @@ DEFUN ("let", Flet, Slet, 1, UNEVALLED, 0, /* Make space to hold the values to give the bound variables. */ EMACS_INT varlist_len = list_length (varlist); SAFE_ALLOCA_LISP (temps, varlist_len); - ptrdiff_t nvars = varlist_len; /* Compute the values and store them in `temps'. */ - for (argnum = 0; argnum < nvars && CONSP (varlist); argnum++) + for (argnum = 0; CONSP (varlist); argnum++) { maybe_quit (); elt = XCAR (varlist); @@ -1017,12 +1016,11 @@ DEFUN ("let", Flet, Slet, 1, UNEVALLED, 0, else temps[argnum] = eval_sub (Fcar (Fcdr (elt))); } - nvars = argnum; lexenv = Vinternal_interpreter_environment; varlist = XCAR (args); - for (argnum = 0; argnum < nvars && CONSP (varlist); argnum++) + for (argnum = 0; CONSP (varlist); argnum++) { Lisp_Object var; diff --git a/test/src/eval-tests.el b/test/src/eval-tests.el index b2b7dfefda..3576254d7d 100644 --- a/test/src/eval-tests.el +++ b/test/src/eval-tests.el @@ -226,4 +226,31 @@ eval-tests/backtrace-in-batch-mode/demoted-errors (should (equal (string-trim (buffer-string)) "Error: (error \"Boo\")"))))) +(ert-deftest eval-tests/let () + (should (equal (let (a) + a) + nil)) + + (should (equal (let (a b) + (list a b)) + '(nil nil))) + + (should (equal (let ((a 1)) + a) + 1)) + + (should (equal (let ((a 1) b) + (list a b)) + '(1 nil))) + + ;; (error "`let' bindings can have only one value-form" a 1 2) + (should-error (let ((a 1 2)) + a) + :type 'error) + + ;; (wrong-type-argument symbolp (a)) + (should-error (let (((a) 1)) + a) + :type 'wrong-type-argument)) + ;;; eval-tests.el ends here -- 2.30.1 ----Next_Part(Tue_Mar__2_11_10_43_2021_296)----