From unknown Mon Aug 11 21:14:36 2025 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Mailer: MIME-tools 5.509 (Entity 5.509) Content-Type: text/plain; charset=utf-8 From: bug#26026 <26026@debbugs.gnu.org> To: bug#26026 <26026@debbugs.gnu.org> Subject: Status: Defining a method named zero? breaks primitive zero? Reply-To: bug#26026 <26026@debbugs.gnu.org> Date: Tue, 12 Aug 2025 04:14:36 +0000 retitle 26026 Defining a method named zero? breaks primitive zero? reassign 26026 guile submitter 26026 Alejandro Sanchez severity 26026 normal thanks From debbugs-submit-bounces@debbugs.gnu.org Wed Mar 08 11:09:56 2017 Received: (at submit) by debbugs.gnu.org; 8 Mar 2017 16:09:56 +0000 Received: from localhost ([127.0.0.1]:46504 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cleA0-0004uL-5b for submit@debbugs.gnu.org; Wed, 08 Mar 2017 11:09:56 -0500 Received: from eggs.gnu.org ([208.118.235.92]:50266) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1clZSR-0002Sb-Mg for submit@debbugs.gnu.org; Wed, 08 Mar 2017 06:08:39 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1clZSL-0007XF-J2 for submit@debbugs.gnu.org; Wed, 08 Mar 2017 06:08:34 -0500 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on eggs.gnu.org X-Spam-Level: X-Spam-Status: No, score=0.8 required=5.0 tests=BAYES_50,T_DKIM_INVALID autolearn=disabled version=3.3.2 Received: from lists.gnu.org ([2001:4830:134:3::11]:33518) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1clZSL-0007XB-G1 for submit@debbugs.gnu.org; Wed, 08 Mar 2017 06:08:33 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41226) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1clZSK-0006xH-DZ for bug-guile@gnu.org; Wed, 08 Mar 2017 06:08:33 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1clZSF-0007Vr-JN for bug-guile@gnu.org; Wed, 08 Mar 2017 06:08:32 -0500 Received: from lb1.openmailbox.org ([5.79.108.160]:59792 helo=mail.openmailbox.org) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1clZSF-0007Up-Ab for bug-guile@gnu.org; Wed, 08 Mar 2017 06:08:27 -0500 Received: by mail.openmailbox.org (Postfix, from userid 20002) id 35B7251626F; Wed, 8 Mar 2017 12:07:59 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=openmailbox.org; s=openmailbox; t=1488971293; bh=hRnSclLA2XPDKOPKgaNwa/0x0//AH0vjQ193WV8Nhpg=; h=From:Subject:Date:To:From; b=t2t360ezEWwpxDuG+Qwxu/EO9y/KzQFLXeWbKEDjR2gsv0uxnanNXDNrGQqI5GoOc lYFcbcqMj/F0MGH/4HlAw9BhdGwfgT1rIUczcE5Kj7GdaaS5iDlLBOEMXXSj7S9DFL f2yYxu5i186CeACbK3lGfyMT1+UKXefqdBL03VWs= From: Alejandro Sanchez DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=openmailbox.org; s=openmailbox; t=1488971279; bh=hRnSclLA2XPDKOPKgaNwa/0x0//AH0vjQ193WV8Nhpg=; h=From:Subject:Date:To:From; b=FJ0MvSi3UtUxsv5cqYlc3UKDPNOEpDB6FPoRHhVkB4Uw1DJb3w/zv3mbDpsp9oBps JkovNbhmNvAiYLqi/6kduO34BEycz31vF+HYccAy8gs0IM+IAQRjUER/p4NSz6P6VW TqzdI99x1Yr/byZHzfynCTnMde/WUu9UraUL2aUE= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Defining a method named zero? breaks primitive zero? Message-Id: Date: Wed, 8 Mar 2017 12:07:56 +0100 To: bug-guile@gnu.org Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) X-Mailer: Apple Mail (2.3124) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 2001:4830:134:3::11 X-Spam-Score: -4.0 (----) X-Debbugs-Envelope-To: submit X-Mailman-Approved-At: Wed, 08 Mar 2017 11:09:55 -0500 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -4.0 (----) If I define a =E2=80=98zero?=E2=80=99 predicate method for a custom = class the primitive =E2=80=98zero?=E2=80=99 is lost. Here is a simple = vector module: ;;; File vector2.scm (define-module (vector2) #:use-module (oop goops) #:export ( get-x get-y zero?)) =09 (define-class () (x #:init-value 0 #:getter get-x #:init-keyword #:x) (y #:init-value 0 #:getter get-y #:init-keyword #:y) ) (define-generic zero?) (define-method (zero? (v )) (and (zero? (get-x v)) (zero? (get-y v)))) In the Guile REPL try executing the following code: scheme@(guile-user)> (use-modules (oop goops) (vector2)) scheme@(guile-user)> (zero? (make )) This will display=20 WARNING: (guile-user): `zero?' imported from both (ice-9 r5rs) = and (vector2) ERROR: In procedure scm-error: ERROR: No applicable method for #< zero? (1)> in call = (zero? 0) =09 Entering a new prompt. Type `,bt' for a backtrace or `,q' to = continue. scheme@(guile-user) [1]> ,bt In vector2.scm: 11:7 2 (_ #< 105e87e00>) In oop/goops.scm: 1438:4 1 (cache-miss 0) In unknown file: 0 (scm-error goops-error #f "No applicable method for = ~S in call ~S" (#< =E2=80=A6) =E2=80=A6) Apparently the problem is that =E2=80=98zero?=E2=80=99 is defined in two = modules and the vector2 definition overrides it. This isn=E2=80=99t the = case with other primitives like =E2=80=98+=E2=80=99 or =E2=80=98*=E2=80=99= , so this seems like a bug? I had built Guile from HEAD a few days ago, = my package manager shows 6fff84d as the version number, so I guess that = must be the hash of the commit HEAD was pointing to at that time.= From debbugs-submit-bounces@debbugs.gnu.org Wed Apr 19 11:12:24 2017 Received: (at 26026-done) by debbugs.gnu.org; 19 Apr 2017 15:12:24 +0000 Received: from localhost ([127.0.0.1]:57050 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1d0rHM-0002kX-0Y for submit@debbugs.gnu.org; Wed, 19 Apr 2017 11:12:24 -0400 Received: from pb-sasl1.pobox.com ([64.147.108.66]:50716 helo=sasl.smtp.pobox.com) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1d0rHK-0002kP-9S for 26026-done@debbugs.gnu.org; Wed, 19 Apr 2017 11:12:22 -0400 Received: from sasl.smtp.pobox.com (unknown [127.0.0.1]) by pb-sasl1.pobox.com (Postfix) with ESMTP id 22D2381D34; Wed, 19 Apr 2017 11:12:20 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type:content-transfer-encoding; s=sasl; bh=aSNHcXs/Jy42 nyqcGHMOcvBDGJI=; b=Ivdk7hhSnqAF8xiBS3N2YhOBJ+O1g82seu9dWPWh7uxj UCTskJvv08zOVcP+STx3ySquDbkpXydhIVtHluE+90phIm007+6+JDdU8b90IyT7 DfkFDTmz1r7U9LWhTViwlZI1z1wuIftZwfCpbPZb8o64ylq1+YBihY8iJCU9Uy0= Received: from pb-sasl1.nyi.icgroup.com (unknown [127.0.0.1]) by pb-sasl1.pobox.com (Postfix) with ESMTP id 1A44581D33; Wed, 19 Apr 2017 11:12:20 -0400 (EDT) Received: from rusty (unknown [88.160.190.192]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by pb-sasl1.pobox.com (Postfix) with ESMTPSA id 3F07681D32; Wed, 19 Apr 2017 11:12:19 -0400 (EDT) From: Andy Wingo To: Alejandro Sanchez Subject: Re: bug#26026: Defining a method named zero? breaks primitive zero? References: Date: Wed, 19 Apr 2017 17:12:12 +0200 In-Reply-To: (Alejandro Sanchez's message of "Wed, 8 Mar 2017 12:07:56 +0100") Message-ID: <87mvbcl9df.fsf@igalia.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Pobox-Relay-ID: 94C7C554-2512-11E7-A9B1-07D2064AB293-02397024!pb-sasl1.pobox.com X-Spam-Score: 0.7 (/) X-Debbugs-Envelope-To: 26026-done Cc: 26026-done@debbugs.gnu.org X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: 0.7 (/) On Wed 08 Mar 2017 12:07, Alejandro Sanchez write= s: > If I define a =E2=80=98zero?=E2=80=99 predicate method for a custom class= the primitive =E2=80=98zero?=E2=80=99 is lost. Here is a simple vector mod= ule: > > ;;; File vector2.scm > (define-module (vector2) > #:use-module (oop goops) > #:export ( get-x get-y zero?)) >=20=09 > (define-class () > (x #:init-value 0 #:getter get-x #:init-keyword #:x) > (y #:init-value 0 #:getter get-y #:init-keyword #:y) ) > > (define-generic zero?) > (define-method (zero? (v )) > (and (zero? (get-x v)) > (zero? (get-y v)))) > > In the Guile REPL try executing the following code: > > scheme@(guile-user)> (use-modules (oop goops) (vector2)) > scheme@(guile-user)> (zero? (make )) > > This will display=20 > > WARNING: (guile-user): `zero?' imported from both (ice-9 r5rs) and (vect= or2) > ERROR: In procedure scm-error: > ERROR: No applicable method for #< zero? (1)> in call (zero? 0) >=20=09 > Entering a new prompt. Type `,bt' for a backtrace or `,q' to continue. > scheme@(guile-user) [1]> ,bt > In vector2.scm: > 11:7 2 (_ #< 105e87e00>) > In oop/goops.scm: > 1438:4 1 (cache-miss 0) > In unknown file: > 0 (scm-error goops-error #f "No applicable method for ~S in c= all ~S" (#< =E2=80=A6) =E2=80=A6) > > Apparently the problem is that =E2=80=98zero?=E2=80=99 is defined in two = modules and > the vector2 definition overrides it. This isn=E2=80=99t the case with oth= er > primitives like =E2=80=98+=E2=80=99 or =E2=80=98*=E2=80=99, so this seems= like a bug? I had built > Guile from HEAD a few days ago, my package manager shows 6fff84d as > the version number, so I guess that must be the hash of the commit > HEAD was pointing to at that time. Actually the (vector2) module makes a fresh definition for zero?. You can tell because zero? is in its export list. So instead of extending the primitive-generic that is zero?, you are making a new definition. See: scheme@(guile-user)> (define-module (foo) #:export (zero?)) $1 =3D # scheme@(foo)> (zero? 0) :4:0: :4:0: Unbound variable: zero? Entering a new prompt. Type `,bt' for a backtrace or `,q' to continue. If you want to extend a primitive-generic, then do that by not exporting zero?. In a way it's like mutating the primitive in place, giving it additional powers. Andy From debbugs-submit-bounces@debbugs.gnu.org Sat Apr 22 10:46:48 2017 Received: (at 26026) by debbugs.gnu.org; 22 Apr 2017 14:46:48 +0000 Received: from localhost ([127.0.0.1]:34559 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1d1wJE-0005nP-4M for submit@debbugs.gnu.org; Sat, 22 Apr 2017 10:46:48 -0400 Received: from lb1.openmailbox.org ([5.79.108.160]:39065 helo=mail.openmailbox.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1d1wJB-0005nG-OL for 26026@debbugs.gnu.org; Sat, 22 Apr 2017 10:46:46 -0400 Received: by mail.openmailbox.org (Postfix, from userid 20002) id AFC95509AA9; Sat, 22 Apr 2017 16:46:44 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=openmailbox.org; s=openmailbox; t=1492872404; bh=VD+ZqvLMRXqEJX7D+2oDwFlBNSnIWXSjVDoSC16ixLY=; h=From:Subject:Date:References:To:In-Reply-To:From; b=BM0/61FCwdKpGmEgPq+fHje2dV+JEL+BwbUXjYIelo6hxBt20lfVZVSOUHc8J+1eL kPEHTmklh+CttN8ylYME1i+TfCfu8We3Bck6C4YviPFlP0L3LkbZwPVoh3uwn9M+qr k9JgfMvA5OeEv/9cI2mdzKegWjJ9ODzot6KtKg+Y= X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on ZDZR002 X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=HTML_MESSAGE,NO_RECEIVED, NO_RELAYS,T_DKIM_INVALID,URIBL_BLOCKED autolearn=disabled version=3.4.0 From: Alejandro Sanchez DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=openmailbox.org; s=openmailbox; t=1492872403; bh=VD+ZqvLMRXqEJX7D+2oDwFlBNSnIWXSjVDoSC16ixLY=; h=From:Subject:Date:References:To:In-Reply-To:From; b=OA9590yiAVgkQY09zaEJkDXwg+QEb3KvxVaMirzdR84Cn4THTu4bCJT79CxxsdpZA TD0vUZloQpyGHfrPZH6p80rXym9OOAPQTcFNKn6KyCSLfnq+tS/YEOpiZ0kzEfg9iv vIPaAsXcfrKzHFtAaA8/kLqSQWuBqNnhApVRi6Qs= Content-Type: multipart/alternative; boundary="Apple-Mail=_A398ED73-2A41-4C37-98FD-277759D280DE" Message-Id: Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Subject: Re: bug#26026: closed (Re: bug#26026: Defining a method named zero? breaks primitive zero?) Date: Sat, 22 Apr 2017 16:46:40 +0200 References: <87mvbcl9df.fsf@igalia.com> To: 26026@debbugs.gnu.org In-Reply-To: X-Mailer: Apple Mail (2.3124) X-Spam-Score: 0.0 (/) X-Debbugs-Envelope-To: 26026 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: 0.0 (/) --Apple-Mail=_A398ED73-2A41-4C37-98FD-277759D280DE Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 This does not work. If I remove the export of =E2=80=98zero?=E2=80=99 I = get another error: scheme@(guile-user)> (zero? (make )) :3:1: :3:1: In procedure =3D: Wrong = type: #< 106606e20> =09 Entering a new prompt. Type `,bt' for a backtrace or `,q' to = continue. scheme@(guile-user) [1]> ,bt In current input: 3:1 0 (_) scheme@(guile-user) [1]> That is why I was exporting =E2=80=98zero?=E2=80=99 to begin with. I do = not have to export =E2=80=98+=E2=80=99 or =E2=80=98-=E2=80=98 for = example. > On 19 Apr 2017, at 17:13, GNU bug Tracking System = wrote: >=20 > Your bug report >=20 > #26026: Defining a method named zero? breaks primitive zero? >=20 > which was filed against the guile package, has been closed. >=20 > The explanation is attached below, along with your original report. > If you require more details, please reply to 26026@debbugs.gnu.org. >=20 > --=20 > 26026: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=3D26026 > GNU Bug Tracking System > Contact help-debbugs@gnu.org with problems >=20 > From: Andy Wingo > Subject: Re: bug#26026: Defining a method named zero? breaks primitive = zero? > Date: 19 April 2017 at 17:12:12 GMT+2 > To: Alejandro Sanchez > Cc: 26026-done@debbugs.gnu.org >=20 >=20 > On Wed 08 Mar 2017 12:07, Alejandro Sanchez = writes: >=20 >> If I define a =E2=80=98zero?=E2=80=99 predicate method for a custom = class the primitive =E2=80=98zero?=E2=80=99 is lost. Here is a simple = vector module: >>=20 >> ;;; File vector2.scm >> (define-module (vector2) >> #:use-module (oop goops) >> #:export ( get-x get-y zero?)) >> =09 >> (define-class () >> (x #:init-value 0 #:getter get-x #:init-keyword #:x) >> (y #:init-value 0 #:getter get-y #:init-keyword #:y) ) >>=20 >> (define-generic zero?) >> (define-method (zero? (v )) >> (and (zero? (get-x v)) >> (zero? (get-y v)))) >>=20 >> In the Guile REPL try executing the following code: >>=20 >> scheme@(guile-user)> (use-modules (oop goops) (vector2)) >> scheme@(guile-user)> (zero? (make )) >>=20 >> This will display=20 >>=20 >> WARNING: (guile-user): `zero?' imported from both (ice-9 r5rs) = and (vector2) >> ERROR: In procedure scm-error: >> ERROR: No applicable method for #< zero? (1)> in call = (zero? 0) >> =09 >> Entering a new prompt. Type `,bt' for a backtrace or `,q' to = continue. >> scheme@(guile-user) [1]> ,bt >> In vector2.scm: >> 11:7 2 (_ #< 105e87e00>) >> In oop/goops.scm: >> 1438:4 1 (cache-miss 0) >> In unknown file: >> 0 (scm-error goops-error #f "No applicable method for = ~S in call ~S" (#< =E2=80=A6) =E2=80=A6) >>=20 >> Apparently the problem is that =E2=80=98zero?=E2=80=99 is defined in = two modules and >> the vector2 definition overrides it. This isn=E2=80=99t the case with = other >> primitives like =E2=80=98+=E2=80=99 or =E2=80=98*=E2=80=99, so this = seems like a bug? I had built >> Guile from HEAD a few days ago, my package manager shows 6fff84d as >> the version number, so I guess that must be the hash of the commit >> HEAD was pointing to at that time. >=20 > Actually the (vector2) module makes a fresh definition for zero?. You > can tell because zero? is in its export list. So instead of extending > the primitive-generic that is zero?, you are making a new definition. > See: >=20 > scheme@(guile-user)> (define-module (foo) #:export (zero?)) > $1 =3D # > scheme@(foo)> (zero? 0) > :4:0: :4:0: Unbound variable: zero? >=20 > Entering a new prompt. Type `,bt' for a backtrace or `,q' to = continue. >=20 > If you want to extend a primitive-generic, then do that by not = exporting > zero?. In a way it's like mutating the primitive in place, giving it > additional powers. >=20 > Andy >=20 >=20 >=20 >=20 > From: Alejandro Sanchez > Subject: Defining a method named zero? breaks primitive zero? > Date: 8 March 2017 at 12:07:56 GMT+1 > To: bug-guile@gnu.org >=20 >=20 > If I define a =E2=80=98zero?=E2=80=99 predicate method for a custom = class the primitive =E2=80=98zero?=E2=80=99 is lost. Here is a simple = vector module: >=20 > ;;; File vector2.scm > (define-module (vector2) > #:use-module (oop goops) > #:export ( get-x get-y zero?)) > =09 > (define-class () > (x #:init-value 0 #:getter get-x #:init-keyword #:x) > (y #:init-value 0 #:getter get-y #:init-keyword #:y) ) >=20 > (define-generic zero?) > (define-method (zero? (v )) > (and (zero? (get-x v)) > (zero? (get-y v)))) >=20 > In the Guile REPL try executing the following code: >=20 > scheme@(guile-user)> (use-modules (oop goops) (vector2)) > scheme@(guile-user)> (zero? (make )) >=20 > This will display=20 >=20 > WARNING: (guile-user): `zero?' imported from both (ice-9 r5rs) = and (vector2) > ERROR: In procedure scm-error: > ERROR: No applicable method for #< zero? (1)> in call = (zero? 0) > =09 > Entering a new prompt. Type `,bt' for a backtrace or `,q' to = continue. > scheme@(guile-user) [1]> ,bt > In vector2.scm: > 11:7 2 (_ #< 105e87e00>) > In oop/goops.scm: > 1438:4 1 (cache-miss 0) > In unknown file: > 0 (scm-error goops-error #f "No applicable method for = ~S in call ~S" (#< =E2=80=A6) =E2=80=A6) >=20 > Apparently the problem is that =E2=80=98zero?=E2=80=99 is defined in = two modules and the vector2 definition overrides it. This isn=E2=80=99t = the case with other primitives like =E2=80=98+=E2=80=99 or =E2=80=98*=E2=80= =99, so this seems like a bug? I had built Guile from HEAD a few days = ago, my package manager shows 6fff84d as the version number, so I guess = that must be the hash of the commit HEAD was pointing to at that time. >=20 >=20 >=20 --Apple-Mail=_A398ED73-2A41-4C37-98FD-277759D280DE Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 This does not work. If I remove the export of =E2=80=98zero?=E2= =80=99 I get another error:

scheme@(guile-user)> =  (zero? (make <vector2>))
= <unnamed port>:3:1: <unnamed port>:3:1: In procedure = =3D: Wrong type: #<<vector2> 106606e20>
=
Entering a new prompt.  Type = `,bt' for a backtrace or `,q' to continue.
= scheme@(guile-user) [1]> ,bt
In = current input:
      3:1  0 = (_)
scheme@(guile-user) = [1]>

That = is why I was exporting =E2=80=98zero?=E2=80=99 to begin with. I do not = have to export =E2=80=98+=E2=80=99 or =E2=80=98-=E2=80=98 for = example.

On 19 Apr 2017, at 17:13, GNU = bug Tracking System <help-debbugs@gnu.org> wrote:

Your bug report

#26026: Defining a method named zero? breaks = primitive zero?

which was filed against the = guile package, has been closed.

The = explanation is attached below, along with your original report.
If you require more details, please reply to 26026@debbugs.gnu.org.

-- =
26026: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=3D26026
GNU Bug Tracking System
Contact help-debbugs@gnu.org = with problems

From: Andy Wingo <wingo@igalia.com>
Subject: = Re: bug#26026: = Defining a method named zero? breaks primitive zero?
Date: 19= April 2017 at 17:12:12 GMT+2
To: = Alejandro Sanchez <hiphish@openmailbox.org>
Cc: = 26026-done@debbugs.gnu.org


On Wed 08 Mar 2017 12:07, Alejandro Sanchez = <hiphish@openmailbox.org> writes:

If I define a = =E2=80=98zero?=E2=80=99 predicate method for a custom class the = primitive =E2=80=98zero?=E2=80=99 is lost. Here is a simple vector = module:

;;; File vector2.scm
= (define-module (vector2)
=  #:use-module (oop goops)
=  #:export (<vector2> get-x get-y zero?))

= (define-class <vector2> ()
 (x = #:init-value 0 #:getter get-x #:init-keyword #:x)
 (y = #:init-value 0 #:getter get-y #:init-keyword #:y) )

= (define-generic zero?)
(define-method (zero? (v = <vector2>))
 (and (zero? (get-x v))
=       (zero? (get-y v))))

In the Guile REPL try executing the following = code:

scheme@(guile-user)> = (use-modules (oop goops) (vector2))
= scheme@(guile-user)> (zero? (make <vector2>))

This will display

= WARNING: (guile-user): `zero?' imported from both (ice-9 r5rs) = and (vector2)
ERROR: In procedure scm-error:
= ERROR: No applicable method for #<<generic> zero? = (1)> in call (zero? 0)

Entering = a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
= scheme@(guile-user) [1]> ,bt
In = vector2.scm:
    11:7 =  2 (_ #<<vector2> 105e87e00>)
In = oop/goops.scm:
  1438:4  1 = (cache-miss 0)
In unknown file:
=           0 = (scm-error goops-error #f "No applicable method for ~S in call ~S" = (#<<gen=E2=80=A6> =E2=80=A6) =E2=80=A6)

Apparently the problem is that =E2=80=98zero?=E2=80=99 is = defined in two modules and
the vector2 definition = overrides it. This isn=E2=80=99t the case with other
primitives like =E2=80=98+=E2=80=99 or =E2=80=98*=E2=80=99, = so this seems like a bug? I had built
Guile from HEAD a = few days ago, my package manager shows 6fff84d as
the = version number, so I guess that must be the hash of the commit
HEAD was pointing to at that time.

Actually the (vector2) module = makes a fresh definition for zero?.  You
can tell = because zero? is in its export list.  So instead of extending
the primitive-generic that is zero?, you are making a new = definition.
See:

=  scheme@(guile-user)> (define-module (foo) #:export (zero?))
 $1 =3D #<directory (foo) 1203c80>
=  scheme@(foo)> (zero? 0)
 <unnamed = port>:4:0: <unnamed port>:4:0: Unbound variable: zero?

 Entering a new prompt.  Type `,bt' = for a backtrace or `,q' to continue.

If you = want to extend a primitive-generic, then do that by not exporting
zero?.  In a way it's like mutating the primitive in = place, giving it
additional powers.

Andy




From: Alejandro Sanchez <hiphish@openmailbox.org>
Subject: = Defining a method = named zero? breaks primitive zero?
Date: = 8 March 2017 at 12:07:56 = GMT+1
To: = bug-guile@gnu.org


If I define a = =E2=80=98zero?=E2=80=99 predicate method for a custom class the = primitive =E2=80=98zero?=E2=80=99 is lost. Here is a simple vector = module:

;;; File vector2.scm
= (define-module (vector2)
=  #:use-module (oop goops)
=  #:export (<vector2> get-x get-y zero?))

= (define-class <vector2> ()
 (x = #:init-value 0 #:getter get-x #:init-keyword #:x)
 (y = #:init-value 0 #:getter get-y #:init-keyword #:y) )

= (define-generic zero?)
(define-method (zero? (v = <vector2>))
 (and (zero? (get-x v))
=       (zero? (get-y v))))

In the Guile REPL try executing the following = code:

scheme@(guile-user)> = (use-modules (oop goops) (vector2))
= scheme@(guile-user)> (zero? (make <vector2>))

This will display

= WARNING: (guile-user): `zero?' imported from both (ice-9 r5rs) = and (vector2)
ERROR: In procedure scm-error:
= ERROR: No applicable method for #<<generic> zero? = (1)> in call (zero? 0)

Entering = a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
= scheme@(guile-user) [1]> ,bt
In = vector2.scm:
    11:7 =  2 (_ #<<vector2> 105e87e00>)
In = oop/goops.scm:
  1438:4  1 = (cache-miss 0)
In unknown file:
=           0 = (scm-error goops-error #f "No applicable method for ~S in call ~S" = (#<<gen=E2=80=A6> =E2=80=A6) =E2=80=A6)

Apparently the problem is that =E2=80=98zero?=E2=80=99 is = defined in two modules and the vector2 definition overrides it. This = isn=E2=80=99t the case with other primitives like =E2=80=98+=E2=80=99 or = =E2=80=98*=E2=80=99, so this seems like a bug? I had built Guile from = HEAD a few days ago, my package manager shows 6fff84d as the version = number, so I guess that must be the hash of the commit HEAD was pointing = to at that time.




= --Apple-Mail=_A398ED73-2A41-4C37-98FD-277759D280DE-- From unknown Mon Aug 11 21:14:36 2025 Received: (at fakecontrol) by fakecontrolmessage; To: internal_control@debbugs.gnu.org From: Debbugs Internal Request Subject: Internal Control Message-Id: bug archived. Date: Sun, 21 May 2017 11:24:04 +0000 User-Agent: Fakemail v42.6.9 # This is a fake control message. # # The action: # bug archived. thanks # This fakemail brought to you by your local debbugs # administrator