From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.bugs Subject: bug#65051: internal_equal manipulates symbols with position without checking symbols-with-pos-enabled. Date: Sun, 13 Aug 2023 16:14:56 +0000 Message-ID: References: <83h6pevnd0.fsf@gnu.org> <838raqvg91.fsf@gnu.org> <83r0ohsqmp.fsf@gnu.org> <83leepsn4t.fsf@gnu.org> <838rapskd2.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="2803"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 65051@debbugs.gnu.org, monnier@iro.umontreal.ca To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sun Aug 13 18:16:28 2023 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 1qVDlS-0000Qi-98 for geb-bug-gnu-emacs@m.gmane-mx.org; Sun, 13 Aug 2023 18:16:26 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qVDl9-00085U-4g; Sun, 13 Aug 2023 12:16:07 -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 1qVDl5-00085M-QE for bug-gnu-emacs@gnu.org; Sun, 13 Aug 2023 12:16:05 -0400 Original-Received: from debbugs.gnu.org ([2001:470:142:5::43]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qVDl4-00076q-Mx for bug-gnu-emacs@gnu.org; Sun, 13 Aug 2023 12:16:03 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1qVDl4-0005nT-Is for bug-gnu-emacs@gnu.org; Sun, 13 Aug 2023 12:16:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Alan Mackenzie Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 13 Aug 2023 16:16:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 65051 X-GNU-PR-Package: emacs Original-Received: via spool by 65051-submit@debbugs.gnu.org id=B65051.169194330622202 (code B ref 65051); Sun, 13 Aug 2023 16:16:02 +0000 Original-Received: (at 65051) by debbugs.gnu.org; 13 Aug 2023 16:15:06 +0000 Original-Received: from localhost ([127.0.0.1]:60133 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1qVDk9-0005m1-Sb for submit@debbugs.gnu.org; Sun, 13 Aug 2023 12:15:06 -0400 Original-Received: from mx3.muc.de ([193.149.48.5]:41404) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1qVDk8-0005lB-00 for 65051@debbugs.gnu.org; Sun, 13 Aug 2023 12:15:04 -0400 Original-Received: (qmail 66615 invoked by uid 3782); 13 Aug 2023 18:14:57 +0200 Original-Received: from acm.muc.de (p4fe152a2.dip0.t-ipconnect.de [79.225.82.162]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Sun, 13 Aug 2023 18:14:57 +0200 Original-Received: (qmail 23572 invoked by uid 1000); 13 Aug 2023 16:14:56 -0000 Content-Disposition: inline In-Reply-To: <838rapskd2.fsf@gnu.org> X-Submission-Agent: TMDA/1.3.x (Ph3nix) X-Primary-Address: acm@muc.de 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-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.bugs:267371 Archived-At: On Sat, Aug 05, 2023 at 16:13:13 +0300, Eli Zaretskii wrote: > > Date: Sat, 5 Aug 2023 13:04:07 +0000 > > Cc: 65051@debbugs.gnu.org, monnier@iro.umontreal.ca, acm@muc.de > > From: Alan Mackenzie > > > > No, only the bare symbol is in the obarray. The symbol with position > > > > itself is a pseudovector, with contents (i) a bare symbol (a Lisp_Object > > > > "pointing at" the obarray) and (ii) the unsigned integer position. > > > Please document this factoid in the ELisp manual, I think it's very > > > important, and having it undocumented is a Bad Thing. > > DONE. The change is near the top of the following patch, amended from > > the previous version. > LGTM, thanks. Here's the latest, probably final, version of the patch. It includes new tests in fns-tests.el, adds paragraphs to the descriptions of `eq' and `equal' in objects.texi, and removes the bit about symbols with position being "stored somewhat like vectors" (at the suggestion of Mattias E.). diff --git a/doc/lispref/objects.texi b/doc/lispref/objects.texi index ad079e0d63a..784d59720ed 100644 --- a/doc/lispref/objects.texi +++ b/doc/lispref/objects.texi @@ -2206,6 +2206,10 @@ Equality Predicates the same object, and @code{eq} returns @code{t} or @code{nil} depending on whether the Lisp interpreter created one object or two. +If @var{object1} or @var{object2} is a symbol with position, @code{eq} +regards it as its bare symbol when @code{symbols-with-pos-enabled} is +non-@code{nil} (@pxref{Symbols with Position}). + @example @group (eq 'foo 'foo) @@ -2363,6 +2367,13 @@ Equality Predicates The @code{equal} function recursively compares the contents of objects if they are integers, strings, markers, vectors, bool-vectors, byte-code function objects, char-tables, records, or font objects. + +If @var{object1} or @var{object2} is a symbol with position, +@code{equal} regards it as its bare symbol when +@code{symbols-with-pos-enabled} is non-@code{nil}. Otherwise +@code{equal} compares two symbols with position by recursively +comparing their components. @xref{Symbols with Position}. + Other objects are considered @code{equal} only if they are @code{eq}. For example, two distinct buffers are never considered @code{equal}, even if their textual contents are the same. diff --git a/doc/lispref/symbols.texi b/doc/lispref/symbols.texi index 34db0caf3a8..1f3b677d7fb 100644 --- a/doc/lispref/symbols.texi +++ b/doc/lispref/symbols.texi @@ -783,10 +783,15 @@ Symbols with Position @cindex bare symbol A @dfn{symbol with position} is a symbol, the @dfn{bare symbol}, -together with an unsigned integer called the @dfn{position}. These -objects are intended for use by the byte compiler, which records in -them the position of each symbol occurrence and uses those positions -in warning and error messages. +together with an unsigned integer called the @dfn{position}. Symbols +with position don't themselves have entries in the obarray (though +their bare symbols do; @pxref{Creating Symbols}). + +Symbols with position are for the use of the byte compiler, which +records in them the position of each symbol occurrence and uses those +positions in warning and error messages. They shouldn't normally be +used otherwise. Doing so can cause unexpected results with basic +Emacs functions such as @code{eq} and @code{equal}. The printed representation of a symbol with position uses the hash notation outlined in @ref{Printed Representation}. It looks like @@ -798,11 +803,20 @@ Symbols with Position For most purposes, when the flag variable @code{symbols-with-pos-enabled} is non-@code{nil}, symbols with -positions behave just as bare symbols do. For example, @samp{(eq -# foo)} has a value @code{t} when that variable -is set (but @code{nil} when it isn't set). Most of the time in Emacs this -variable is @code{nil}, but the byte compiler binds it to @code{t} -when it runs. +positions behave just as their bare symbols would. For example, +@samp{(eq # foo)} has a value @code{t} when the +variable is set; likewise, @code{equal} will treat a symbol with +position argument as its bare symbol. + +When @code{symbols-with-pos-enabled} is @code{nil}, any symbols with +position continue to exist, but do not behave as symbols, or have the +other useful properties outlined in the previous paragraph. @code{eq} +returns @code{t} when given identical arguments, and @code{equal} +returns @code{t} when given arguments with @code{equal} components. + +Most of the time in Emacs @code{symbols-with-pos-enabled} is +@code{nil}, but the byte compiler and the native compiler bind it to +@code{t} when they run. Typically, symbols with position are created by the byte compiler calling the reader function @code{read-positioning-symbols} @@ -810,17 +824,17 @@ Symbols with Position @code{position-symbol}. @defvar symbols-with-pos-enabled -When this variable is non-@code{nil}, symbols with position behave +When this variable is non-@code{nil}, a symbol with position behaves like the contained bare symbol. Emacs runs a little more slowly in this case. @end defvar @defvar print-symbols-bare -When bound to non-@code{nil}, the Lisp printer prints only the bare symbol of -a symbol with position, ignoring the position. +When bound to non-@code{nil}, the Lisp printer prints only the bare +symbol of a symbol with position, ignoring the position. @end defvar -@defun symbol-with-pos-p symbol. +@defun symbol-with-pos-p symbol This function returns @code{t} if @var{symbol} is a symbol with position, @code{nil} otherwise. @end defun diff --git a/src/fns.c b/src/fns.c index d7b2e7908b6..9b300d503ff 100644 --- a/src/fns.c +++ b/src/fns.c @@ -2773,10 +2773,13 @@ internal_equal (Lisp_Object o1, Lisp_Object o2, enum equal_kind equal_kind, /* A symbol with position compares the contained symbol, and is `equal' to the corresponding ordinary symbol. */ - if (SYMBOL_WITH_POS_P (o1)) - o1 = SYMBOL_WITH_POS_SYM (o1); - if (SYMBOL_WITH_POS_P (o2)) - o2 = SYMBOL_WITH_POS_SYM (o2); + if (symbols_with_pos_enabled) + { + if (SYMBOL_WITH_POS_P (o1)) + o1 = SYMBOL_WITH_POS_SYM (o1); + if (SYMBOL_WITH_POS_P (o2)) + o2 = SYMBOL_WITH_POS_SYM (o2); + } if (BASE_EQ (o1, o2)) return true; @@ -2824,8 +2827,8 @@ internal_equal (Lisp_Object o1, Lisp_Object o2, enum equal_kind equal_kind, if (ASIZE (o2) != size) return false; - /* Compare bignums, overlays, markers, and boolvectors - specially, by comparing their values. */ + /* Compare bignums, overlays, markers, boolvectors, and + symbols with position specially, by comparing their values. */ if (BIGNUMP (o1)) return mpz_cmp (*xbignum_val (o1), *xbignum_val (o2)) == 0; if (OVERLAYP (o1)) @@ -2857,6 +2860,11 @@ internal_equal (Lisp_Object o1, Lisp_Object o2, enum equal_kind equal_kind, if (TS_NODEP (o1)) return treesit_node_eq (o1, o2); #endif + if (SYMBOL_WITH_POS_P(o1)) /* symbols_with_pos_enabled is false. */ + return (BASE_EQ (XSYMBOL_WITH_POS (o1)->sym, + XSYMBOL_WITH_POS (o2)->sym) + && BASE_EQ (XSYMBOL_WITH_POS (o1)->pos, + XSYMBOL_WITH_POS (o2)->pos)); /* Aside from them, only true vectors, char-tables, compiled functions, and fonts (font-spec, font-entity, font-object) diff --git a/test/src/fns-tests.el b/test/src/fns-tests.el index 79ae4393f40..9c09e4f0c33 100644 --- a/test/src/fns-tests.el +++ b/test/src/fns-tests.el @@ -98,6 +98,26 @@ (should-not (equal-including-properties #("a" 0 1 (k "v")) #("b" 0 1 (k "v"))))) +(ert-deftest fns-tests-equal-symbols-with-position () + "Test `eq' and `equal' on symbols with position." + (let ((foo1 (position-symbol 'foo 42)) + (foo2 (position-symbol 'foo 666)) + (foo3 (position-symbol 'foo 42))) + (let (symbols-with-pos-enabled) + (should (eq foo1 foo1)) + (should (equal foo1 foo1)) + (should-not (eq foo1 foo2)) + (should-not (equal foo1 foo2)) + (should-not (eq foo1 foo3)) + (should (equal foo1 foo3))) + (let ((symbols-with-pos-enabled t)) + (should (eq foo1 foo1)) + (should (equal foo1 foo1)) + (should (eq foo1 foo2)) + (should (equal foo1 foo2)) + (should (eq foo1 foo3)) + (should (equal foo1 foo3))))) + (ert-deftest fns-tests-reverse () (should-error (reverse)) (should-error (reverse 1)) -- Alan Mackenzie (Nuremberg, Germany).