From unknown Sun Jun 22 07:40:09 2025 X-Loop: help-debbugs@gnu.org Subject: bug#58727: 29.0.50; rx doc: Semantics of RX... Resent-From: Michael Heerdegen Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 23 Oct 2022 02:33:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: report 58727 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: 58727@debbugs.gnu.org X-Debbugs-Original-To: bug-gnu-emacs@gnu.org Received: via spool by submit@debbugs.gnu.org id=B.166649234931256 (code B ref -1); Sun, 23 Oct 2022 02:33:02 +0000 Received: (at submit) by debbugs.gnu.org; 23 Oct 2022 02:32:29 +0000 Received: from localhost ([127.0.0.1]:42692 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1omQmq-000884-Sq for submit@debbugs.gnu.org; Sat, 22 Oct 2022 22:32:29 -0400 Received: from lists.gnu.org ([209.51.188.17]:38086) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1omQmm-00087u-EL for submit@debbugs.gnu.org; Sat, 22 Oct 2022 22:32:27 -0400 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 1omQmm-0005IW-65 for bug-gnu-emacs@gnu.org; Sat, 22 Oct 2022 22:32:24 -0400 Received: from mout.web.de ([212.227.15.3]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1omQmi-0006zV-1M for bug-gnu-emacs@gnu.org; Sat, 22 Oct 2022 22:32:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=s29768273; t=1666492337; bh=r6gBLim2dbFhVgOVWdBJmTyHTJzEdDNvx5AtYdbCwkY=; h=X-UI-Sender-Class:From:To:Subject:Date; b=GJxLxI56GROgpN6eJ3sR071XyQ+bCq8+/X5s/4obuPJmfGy08p63bR/DP30LkYbw9 mCMt1jSLftKzAKXbvvpHn6jJPNmYE+PLYPwiuADXBc4FQZBTUbJA/fKsxDaAdFJ0uY HFDN0nZ7ZY80GojLd/bzbK7KRtkEyLGDwQlCkzG6/Fe9jUy4+EvYTM1/tCtk1hsbOr uxHS5RvGs9VKSZECGZ37cxdQPKLlcUfTmbisKBcGV7671vkq4rMB64RSBbJjEnD0Oh f+pumDeWdCJtxhDGorUZWB2KMI9uUhxVuvmSxkxNM4QtsxqDBrck6wBtqj0HcwCiav 5RsM9crm+3RgQ== X-UI-Sender-Class: 814a7b36-bfc1-4dae-8640-3722d8ec6cd6 Received: from drachen.dragon ([188.105.185.54]) by smtp.web.de (mrweb005 [213.165.67.108]) with ESMTPSA (Nemesis) id 1MQ8Wa-1oQWDB3B56-00MBdg; Sun, 23 Oct 2022 04:32:17 +0200 From: Michael Heerdegen Date: Sun, 23 Oct 2022 04:32:17 +0200 Message-ID: <87tu3v2rta.fsf@web.de> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:nXm9M5LUoQ9PAdzi6QbPGXeA6Y8LM5r6gevVtpukdnq5OplJf5L q7+SFbsGr7Pu2eGqaOquW/sEBPi9hxbGiizptwOmRd6NLwvP7R1Sw8sezmCqltD24Re0ZMA H2wFx/NsN9ff2sZId5+G5oH9ZWrxNSujjAGBrlGv+NTXrjyUqsV7gZhPcRSsg3j/zpUqwiD Byt9E7zJdaMR83zy7Rplg== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:jbm2G1ni24w=;oVsf5UdDWqWb7OmA1fYIYyN7Dlf 1kWq8RJKrfj6T/3xrZH2lWJLUCmFoDvFFGmwG7amBX9UMMdm0JgE5qV1guRuX7FsehGS6QCNk ozsNI1Ta/GMl3KH394rDzw/xVeVLsKNfUoo8R99IPXZT9Lgqka0JuGihGOUh0kwsrrPcElVd+ VqF9upE3mghJY8h8YC2AggKXs/OODoMR3AA5mXt3qN59eI7VZtiUPZ/Kkbi+9w03WZ4eqZk9e DP019C+A65JqhQaY3JZcMXAP0GqGGuM72ZIwCxsaSLMRb0vVqqCjF/VoZxoFy3mRz2mlQ0OcQ 7Bx4hgQIjInX5xxMBEwsEgIS2n04klZ90+0ThIGmYMlgKPxfowd6w7je/gnIouzmbVgwEgBGP RsQ1wKQspO/IBbGiMw8bvMahirO6jdo60ckGD0fczwwx3jR/reJggCZxZf5b2w4CHnUccugYr fxudDeRzPsDDgChnI+KyCvXL/oPAhP+szxLTWq1IYHrfkUL+T9kmUq8z/G5q18tOBbSdeY1ni sHQyovHvkKV6PI956dG8CDlJGKiDF/Sd2nkSpMaAw0eREEI8KV8Y87MwzyX1+2xbHlw38CmSe G7BGfvi+J/OcluOwE8bqOiJ7jo1EdFddQp7TjF8zKJ5NlhX4MwfydCluhh/Ve/U/gdWZsGV6N /QgxPOSCJ3o9c01i5n7+EuWNGj2AuCgyNrug5E2QmdTC8RF3OlDKNMwcosbg3hSb+wwtwkAoL nMKDkzlkN30LdTTaWVVxS78prNKxYye7DXUv3Gvl0QFKR+iSQ4n2Q4cTdMQ884GHApZVfIz1u jzXNu+bQ2mA7sOV7e82Y/ZeEm3rnWNipC4RDZugF+O6Sca5Lwe7grwUL6rxX3kOFkyO6sFwgr mjs4M3X6j/Z/8xKQvfKewUd85jAGk25u3D9jrJM2MLv+cxhEFO0S3bCZmZZFINxdoFjztPDgf pvuVR4wP6o3FcYU1KX7FXKWJuVY= Received-SPF: pass client-ip=212.227.15.3; envelope-from=michael_heerdegen@web.de; helo=mout.web.de X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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_FROM=0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-Spam-Score: -0.7 (/) 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: -2.4 (--) Hello, please document the semantics of multiple RXs for the RX repetition operators (and maybe grouping operators, too). The resulting regexps are concatenating like with an implicit `seq'. This is not trivial, though: in stringish regexps the repetition operators are only unary, and different interpretations would make sense for `rx' (implicit `seq', implicit `or'). The docstring of `rx' doesn't tell anything about this. The manual has sentences like | =E2=80=98(zero-or-more RX...)=E2=80=99 | =E2=80=98(0+ RX...)=E2=80=99 | Match the RXs zero or more times. Greedy by default. | Corresponding string regexp: =E2=80=98A*=E2=80=99 (greedy), =E2=80= =98A*?=E2=80=99 (non-greedy) but that suffers from the same problem that the semantics of A are not clear: A =3D=3D (seq RX...) ? Oh, and maybe let's also make more clear that `rx' always cares about implicit grouping when necessary. For example, in (info "(elisp) Rx Constructs") it's not trivial that e.g. in =E2=80=98(seq RX...)=E2=80=99 =E2=80=98(sequence RX...)=E2=80=99 =E2=80=98(: RX...)=E2=80=99 =E2=80=98(and RX...)=E2=80=99 Match the RXs in sequence. Without arguments, the expression matches the empty string. Corresponding string regexp: =E2=80=98AB...=E2=80=99 (subexpressions i= n sequence). `rx' silently adds shy grouping to the result, and the corresponding string regexp in this case is more precisely \(?:AB...\). I think it is enough to mention this implicit grouping feature once, but it is important to spell it out. =20=20 TIA, Michael. From unknown Sun Jun 22 07:40:09 2025 X-Loop: help-debbugs@gnu.org Subject: bug#58727: 29.0.50; rx doc: Semantics of RX... References: <87tu3v2rta.fsf@web.de> In-Reply-To: <87tu3v2rta.fsf@web.de> Resent-From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 23 Oct 2022 16:15:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 58727 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: Michael Heerdegen Cc: 58727@debbugs.gnu.org Received: via spool by 58727-submit@debbugs.gnu.org id=B58727.166654166022253 (code B ref 58727); Sun, 23 Oct 2022 16:15:01 +0000 Received: (at 58727) by debbugs.gnu.org; 23 Oct 2022 16:14:20 +0000 Received: from localhost ([127.0.0.1]:46411 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1omdcC-0005mp-CR for submit@debbugs.gnu.org; Sun, 23 Oct 2022 12:14:20 -0400 Received: from mail-lj1-f171.google.com ([209.85.208.171]:38819) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1omdcA-0005mc-Vu for 58727@debbugs.gnu.org; Sun, 23 Oct 2022 12:14:19 -0400 Received: by mail-lj1-f171.google.com with SMTP id bn35so1253634ljb.5 for <58727@debbugs.gnu.org>; Sun, 23 Oct 2022 09:14:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=to:cc:date:message-id:subject:mime-version :content-transfer-encoding:from:sender:from:to:cc:subject:date :message-id:reply-to; bh=VsYYfUfC6MSVW/AiHq8jSJ4q7pPYwy7ouQSwG+aBn8E=; b=KD8mhnOAVrA9hyM2x5fe0HuxX/e0IZ/bc1AayD6WuvkxPTQeUVVarVk78ouaw7ZwLH 1FC+k7ac6Ne6JWAeXl/m3z9q40OUUKC6iH6GufJvQ2SHk/kzLQnf4/QY4nP+f+8ramOy eFiTTTNeO6PJhmNYSvghJ/mb7tU6h4nz0cu3yeXJNSBr9wS1RHL1gtdU7JkqpD4gqx5J UCxvd4TEHr25dDMx42A+ZLFscWLZBZZVnmdN0Wm+oyJNRgikzLzvfV6rrHq5BaoRVVzh MsPR6OloTUFtxoMcZikyNeR+tVd4hpg4hKmddHry29YjHuFOPmsTI+UOp7dS6SrM3qxq b9rg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:cc:date:message-id:subject:mime-version :content-transfer-encoding:from:sender:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=VsYYfUfC6MSVW/AiHq8jSJ4q7pPYwy7ouQSwG+aBn8E=; b=6pyWfIE2oDYUtQule9ajcz6WRSGRk8TmmaFLzh6ktm35G82XZTg74NHzcT7U/ikA4Z weWpgHHYbOsSGJC6b56pFuCQ/A+eZJIBCwDFLPpe6X0owK1rMQQgUxziJdRZqATEYITd 1KAEwrSnZ6DEd0YzmQJR1wt0RjcfLcoi3dUpsJuHEqobmHPtoIlQBqx+1BQskRfZPOPc LmhdCAhUKH2LO0+DDkkh1ygD7XESxlDzzoihtgLYE8fiCssvwSXeeyQVRRhISOMnyC0u APWgZVNY0tn7S8EZIh+9KhwEPaUypWs1NAu7s4kmoeUTlir8pm/c9oUjYxNZWxCZ61Jk xdpg== X-Gm-Message-State: ACrzQf3bealr4G1OfbpYBJCnvtizt0HT0hDU+IafXvubO20Ni8lemTFR gNH2BKXO6ZDwQ6mT0c09I7U= X-Google-Smtp-Source: AMsMyM6KPXV1nigFQkL9k8uI4JuApquMod7UClXsE99FHFm2UtR+1YvjGJvZE4/6/vUgcNPmi4cEhQ== X-Received: by 2002:a2e:9c0c:0:b0:26f:c02b:69cf with SMTP id s12-20020a2e9c0c000000b0026fc02b69cfmr9820763lji.309.1666541652850; Sun, 23 Oct 2022 09:14:12 -0700 (PDT) Received: from smtpclient.apple (c188-150-171-209.bredband.tele2.se. [188.150.171.209]) by smtp.gmail.com with ESMTPSA id t20-20020a056512069400b004994117b0fdsm4082453lfe.281.2022.10.23.09.14.11 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 23 Oct 2022 09:14:12 -0700 (PDT) From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.120.0.1.13\)) Message-Id: <3BB74199-7826-41F5-96BA-39CB3EC0E2B7@gmail.com> Date: Sun, 23 Oct 2022 18:14:10 +0200 X-Mailer: Apple Mail (2.3654.120.0.1.13) X-Spam-Score: 0.0 (/) 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: -1.0 (-) > The resulting regexps are concatenating like with an implicit `seq'. > This is not trivial, though: in stringish regexps the repetition > operators are only unary, and different interpretations would make = sense > for `rx' (implicit `seq', implicit `or'). The rule is implicit concatenation unless specified otherwise; maybe we = could say that in the leading paragraph. (`or` is the only place where = concatenation isn't done.) Otherwise I think we should grant our readers some common sense. It's = not a formal specification but meant for humans to understand, and I'm = quite sure they do. > Oh, and maybe let's also make more clear that `rx' always cares about > implicit grouping when necessary. No, there is no such thing in rx. The manual provides corresponding = string-notation constructs for orientation only. This is important -- rx forms are defined by their semantics, not by = what strings they translate to. From unknown Sun Jun 22 07:40:09 2025 X-Loop: help-debbugs@gnu.org Subject: bug#58727: 29.0.50; rx doc: Semantics of RX... Resent-From: Michael Heerdegen Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 24 Oct 2022 02:35:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 58727 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Cc: 58727@debbugs.gnu.org Received: via spool by 58727-submit@debbugs.gnu.org id=B58727.166657886223763 (code B ref 58727); Mon, 24 Oct 2022 02:35:02 +0000 Received: (at 58727) by debbugs.gnu.org; 24 Oct 2022 02:34:22 +0000 Received: from localhost ([127.0.0.1]:46729 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1omnIE-0006BD-4s for submit@debbugs.gnu.org; Sun, 23 Oct 2022 22:34:22 -0400 Received: from mout.web.de ([217.72.192.78]:47253) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1omnI9-0006Av-Qi for 58727@debbugs.gnu.org; Sun, 23 Oct 2022 22:34:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=s29768273; t=1666578850; bh=fjxvmatIze/EkgagLASSmXvT3DN9Rebh8XGhHH+RlV0=; h=X-UI-Sender-Class:From:To:Cc:Subject:In-Reply-To:References:Date; b=diTFoa0ub70Z4xTTT2llGrTliKao3352xTdNmN6PcGt6+l6TMi2lhwbLuKMsHbpdN rFW0tQXIseWn9A3C4p4+BJD5StN1NGMqP4FepoY3q4QQTyjtHfQuKVZM1j+/rBk8Wi V/YxUOkrTwhLNQR7WjWZrZa3c+XMkeo+m/mFelUtyMHAXmpuSSy5ZtAVbRtWiZN37x YGOZl0kFoyJwqI6a6vp7mknNX2hF3ihk3FWGs8fpfFk8NRXiplmUG4PxB6P5BehxRc 3qeqFQfr4IPFabMJCoQtZp/VDo9U5h8Hl55m/DTQfDzhBA/7ImvnoVfmiCVIYFm3i9 vQguapKAZ5shw== X-UI-Sender-Class: 814a7b36-bfc1-4dae-8640-3722d8ec6cd6 Received: from drachen.dragon ([188.105.185.54]) by smtp.web.de (mrweb106 [213.165.67.124]) with ESMTPSA (Nemesis) id 1MxpmW-1p1Pw43AeU-00zXsT; Mon, 24 Oct 2022 04:34:10 +0200 From: Michael Heerdegen In-Reply-To: <3BB74199-7826-41F5-96BA-39CB3EC0E2B7@gmail.com> ("Mattias =?UTF-8?Q?Engdeg=C3=A5rd?="'s message of "Sun, 23 Oct 2022 18:14:10 +0200") References: <3BB74199-7826-41F5-96BA-39CB3EC0E2B7@gmail.com> Date: Mon, 24 Oct 2022 04:34:09 +0200 Message-ID: <87pmeic5lq.fsf@web.de> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:OimV/yxgarzypBAoyUOiQ2uvcVYBkDu2PMLMexaTzt4u5YYEbaF Iom6Y1L4jkah30ZUdiXeO6svbv9xIGR0murcORC9zeRSSZeHyy1NfUC1KxlTGAE1q5MPq9N KOKhZ0DEF0D7WRorYD1ean2Twp8XWIIEChX/dUezHdxi7cie2b+k5BMLGb3SXKjVXthYEVV iYiqAQPfmyXmt/fV+XvuA== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:7amWzK/y+rg=;+s6uu9uxSgQdzDHz1fIdSLYow9Q EGcbXXO3oEHr0R6GyMIZ0HIPlHEg5FA0HYQ6m9+P7UemR+WGqUb8Cmq3WyCRRw3Dpj9eB3FUc V4O4PbKcQEZlWP+KHxi2o+snZPKLeY9csKJP4zmQGlpYoEmkD+CyiciMtCU2NU9+b1JLCj+LD hrbZ41/8Sc+xggzAD/vbeuaXdtaYUqq/cKn00j1Jk5GIioDfg+aZHhQn3KMpFiS0aaoFH1zhr EaIM6sy/bU0p2oqLOV6DficJx4RRih564PEGKvYwKC3eGvYVkM6gQ5mNokZ9xxT2Jfn/YsXGZ MrAg6ejIzTeQ19trTNW1039Tzvoc1+BY8e6/UKT5CoCjsjwZrCgAT6LayAaTSK6lrNn+iyKe6 iyYGfLtJg0ntkuUenleEiesh/1SdQwtIWyuguiuU6mZjxoFyyffAR+HrUA//ML0+3cwZnXfSx ZEmB93jiA+7cLHVnNou6F2W5iqxw6vpR8+2aFtLbHsHh7CqS3zctOS4enu/yxVwrbxUPYxQAL LO2gQXuFXoRRVnMcVDtBOS4E5kqTE26A/EW5Jg9QHca81iBklFO3hkc93ureAXKByskgzc2SE Gx0/apNGzGAkDGqgKvB/zd10YGkJpBa21hJSPZTf/BkcR5jJMLGKoZUhxEeyqVHngGDgC2zxY r9PuL7fVo77LoEjOvbrwfBquQOA8fW+TikJqRH6OCHsWp+Tm5DZDmxK++gxF2rTSzKZpFZ8KG jjvmkLNcxpi96vc66ivh0pFLTd2y6279iZ016mp1jw9UO7D+wlI+gGZRwvu0HYQVyI7acIKk4 4T54VYLM8bl5O1N4M1kmD3LNZ21PRf6/cSem5SaSsdg+2dJKwVSo3ckgrucN6BYxGsS7BksB2 5sutbDoFDtUBgdiutoCAMFHvHqaqrwu/5NiDHA4+GTtEwwQ9r5v3jUUAeKo08G5OU6JkN5KxY yjwKXhozHuUEcm/ev8z8ZhYzEYw= X-Spam-Score: -0.7 (/) 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: -1.7 (-) Mattias Engdeg=C3=A5rd writes: > > The resulting regexps are concatenating like with an implicit `seq'. > > This is not trivial, though: in stringish regexps the repetition > > operators are only unary, and different interpretations would make sense > > for `rx' (implicit `seq', implicit `or'). > > The rule is implicit concatenation unless specified otherwise; maybe > we could say that in the leading paragraph. (`or` is the only place > where concatenation isn't done.) Yes, that would be good. > > Oh, and maybe let's also make more clear that `rx' always cares > > about implicit grouping when necessary. > > No, there is no such thing in rx. I think you misunderstood what I meant, I meant the implicit shy grouping added in the return value, as in (rx (or "ab" "cd")) =3D=3D> "\\(?:ab\\|cd\\)" ^^^^^ ^^^ > The manual provides corresponding string-notation constructs for > orientation only. This is important -- rx forms are defined by their > semantics, not by what strings they translate to. Is this trivial however? Is it clear that, even for people that see rx more as a translator to stringish regexps, `rx' is that smart? A sentence like "rx forms are defined by their semantics" would help to make that clear I think. Dunno, I'm just guessing that here is a potential for misunderstanding. Telling about the implicit concatenation of RX... is the more important point for me. Thanks so far, Michael.=20 From unknown Sun Jun 22 07:40:09 2025 X-Loop: help-debbugs@gnu.org Subject: bug#58727: 29.0.50; rx doc: Semantics of RX... Resent-From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 24 Oct 2022 12:50:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 58727 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: To: Michael Heerdegen Cc: 58727@debbugs.gnu.org Received: via spool by 58727-submit@debbugs.gnu.org id=B58727.166661577921734 (code B ref 58727); Mon, 24 Oct 2022 12:50:01 +0000 Received: (at 58727) by debbugs.gnu.org; 24 Oct 2022 12:49:39 +0000 Received: from localhost ([127.0.0.1]:47351 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1omwtf-0005eU-7V for submit@debbugs.gnu.org; Mon, 24 Oct 2022 08:49:39 -0400 Received: from mail-lj1-f180.google.com ([209.85.208.180]:42660) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1omwta-0005eC-Sf for 58727@debbugs.gnu.org; Mon, 24 Oct 2022 08:49:38 -0400 Received: by mail-lj1-f180.google.com with SMTP id bs14so12626445ljb.9 for <58727@debbugs.gnu.org>; Mon, 24 Oct 2022 05:49:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:sender:from:to:cc:subject :date:message-id:reply-to; bh=J00ltKTZld0qVnMsG2t6G5VjJSQLwQC14T5F+gr99Rc=; b=h7DV8VJZNuTBbPB+ntaEW+INkrnpOGK20dHmbpvZa+DUVBP+kPM7nrsFaTGXj7RnhK 8cjjRb4yxmHDaa1j0C3UEu/6GVidn2iB0MoTkqAg1GYcYgGpLT/pzTVwV2EfJCZNNt7m sHGA46WqgyWhTsfNFIbe22v/rcjf4qw4LbxuwMmR3StWkf99J9YNzH5gNvsv/P6rCpAT PkcyUKiAt3Dv6v3+A4hS0dirO9gED0ZY87ArbyVI14IExKnJ+8/69njeZSPRtXwZGvNP Q6OQk9W8X6V4ljl5fGnNa7CQStChA/zm31ZZsm9U8iezHINWaU0h4QshpnW+2uvTjyQz ARXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:sender:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=J00ltKTZld0qVnMsG2t6G5VjJSQLwQC14T5F+gr99Rc=; b=oCTtfyuNupoIDlfbtmJ+Ix+efiXQIF+IBCJ9F3YAtODFNOhoU3Wa4JXGRkKprtNV7X vb9+sUQvsJx/VBRtClqDk95VqYbwYnntusyLXIBXHZLcOWW2Eoup9pmHBfZg+xEg3neG GQM2OEdBb3SMrUOy3ckxb7FeSnw/GWYoPQKqopDFeGiFF7Q/YKqMEcPCsVgkhFy2yxBB SJKtBSQpmpArnL9JQtaj6ToRfjWYOnTeUAM/7LBCU5CxwAJibdnucBxZqG7G8u6Zks2b MDt8eXEFTlCyskNWT/IT9HtZ7Ei+zs2pUTOArWvQ3EESUhpqc7WFu2HBUoe6VmyAid2t lCMg== X-Gm-Message-State: ACrzQf0ygr/BqzwUnRLIm3IMTVJz+DTStIxJ2aNFa0mInmLI2I0HfZ67 Mmmot7n9F13w9Y/m9oK9vY0= X-Google-Smtp-Source: AMsMyM6C1eEFVbBHisGlLx3PvZNrhS8EaE2XqwYa6Rsel+el2123kt5uMjHHpOdjUpOlzW/LCrWo1A== X-Received: by 2002:a05:651c:d7:b0:26f:e175:cefa with SMTP id 23-20020a05651c00d700b0026fe175cefamr11213598ljr.302.1666615768565; Mon, 24 Oct 2022 05:49:28 -0700 (PDT) Received: from smtpclient.apple (c188-150-171-209.bredband.tele2.se. [188.150.171.209]) by smtp.gmail.com with ESMTPSA id w3-20020a19c503000000b00492ea54beeasm4517009lfe.306.2022.10.24.05.49.27 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 24 Oct 2022 05:49:28 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.120.0.1.13\)) From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= In-Reply-To: <87pmeic5lq.fsf@web.de> Date: Mon, 24 Oct 2022 14:49:25 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: References: <3BB74199-7826-41F5-96BA-39CB3EC0E2B7@gmail.com> <87pmeic5lq.fsf@web.de> X-Mailer: Apple Mail (2.3654.120.0.1.13) X-Spam-Score: 0.0 (/) 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: -1.0 (-) 24 okt. 2022 kl. 04.34 skrev Michael Heerdegen = : >> The rule is implicit concatenation unless specified otherwise; maybe >> we could say that in the leading paragraph. (`or` is the only place >> where concatenation isn't done.) >=20 > Yes, that would be good. Now added. > I meant the implicit shy > grouping added in the return value Yes, and this is simply not a problem in rx, nor on the abstract regexp = level -- it's just a feature of the surface syntax of string regexps but = that's not something that the rx docs are or should be preoccupied with. (For that matter, 'shy grouping' is terrible terminology: it's obscure = wording for something that is generally known as bracketing to the = general population.) > (rx (or "ab" "cd")) =3D=3D> "\\(?:ab\\|cd\\)" > ^^^^^ ^^^ This happens to be a cosmetic flaw in rx: in this case the brackets = shouldn't be there at all, but getting rid of them is currently more = trouble than it's worth. It does not affect matching performance. See it = as an excess of packaging material which does not increase the shipping = costs. >> The manual provides corresponding string-notation constructs for >> orientation only. This is important -- rx forms are defined by their >> semantics, not by what strings they translate to. >=20 > Is this trivial however? Is it clear that, even for people that see = rx > more as a translator to stringish regexps, `rx' is that smart? It's not that rx is smart, it's that it's not completely broken. = Mentioning that rx adds brackets now and then is tantamount to saying = that it's not buggy.=20 We don't say that the byte-compiler emits jump instructions as needed, = not just because it's superfluous information but also because such a = statement suggests that it's not. > A sentence like "rx forms are defined by their semantics" would help = to > make that clear I think. Well, I added a phrase to that effect as well. Thank you for your comments and suggestions! From unknown Sun Jun 22 07:40:09 2025 MIME-Version: 1.0 X-Mailer: MIME-tools 5.505 (Entity 5.505) X-Loop: help-debbugs@gnu.org From: help-debbugs@gnu.org (GNU bug Tracking System) To: Michael Heerdegen Subject: bug#58727: closed (Re: 29.0.50; rx doc: Semantics of RX...) Message-ID: References: <87mt9klirz.fsf@web.de> <87tu3v2rta.fsf@web.de> X-Gnu-PR-Message: they-closed 58727 X-Gnu-PR-Package: emacs Reply-To: 58727@debbugs.gnu.org Date: Tue, 25 Oct 2022 02:50:02 +0000 Content-Type: multipart/mixed; boundary="----------=_1666666202-27259-1" This is a multi-part message in MIME format... ------------=_1666666202-27259-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Your bug report #58727: 29.0.50; rx doc: Semantics of RX... which was filed against the emacs package, has been closed. The explanation is attached below, along with your original report. If you require more details, please reply to 58727@debbugs.gnu.org. --=20 58727: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=3D58727 GNU Bug Tracking System Contact help-debbugs@gnu.org with problems ------------=_1666666202-27259-1 Content-Type: message/rfc822 Content-Disposition: inline Content-Transfer-Encoding: 7bit Received: (at 58727-done) by debbugs.gnu.org; 25 Oct 2022 02:49:32 +0000 Received: from localhost ([127.0.0.1]:49903 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1onA0R-00074r-Uk for submit@debbugs.gnu.org; Mon, 24 Oct 2022 22:49:32 -0400 Received: from mout.web.de ([212.227.15.3]:35997) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1onA0Q-00074d-6j for 58727-done@debbugs.gnu.org; Mon, 24 Oct 2022 22:49:30 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=s29768273; t=1666666161; bh=FdLscJUhCFenoNRGIVK3B0P7BDO9ykXo07WbNUzuAB4=; h=X-UI-Sender-Class:From:To:Cc:Subject:In-Reply-To:References:Date; b=TBZVHpOpF269yRp8KFNYoup/kewfZBpQHde6Nh+9MpQLHQ+xa+Ad1j2P8tKDF5fGe 6fcGK8E/DDDu3NIqwIWw+4FzzJ9gJ6LupFjcdbFY2evFTnCAzX1olnYwtYcY8XAZvJ WUmVEVWgsSns2/9ngAKMF8g5y8KaDtwltgCn7GQ/vTeDU0isKSO0TjC+bYtQkYxsn8 mjQRvvFqA/gNb8Fn4mXHFyHOvOUonf3SumnmATzhTL04ev75SpO3MfZROb5oJYxpJ7 5eIZokgeb08np8eaAnq7B9m5kXLq0DmAz99anYJkWP4wW3NeOYGWw8NCuHtdUhked4 TOt6vUOR3fcgg== X-UI-Sender-Class: 814a7b36-bfc1-4dae-8640-3722d8ec6cd6 Received: from drachen.dragon ([188.104.14.82]) by smtp.web.de (mrweb006 [213.165.67.108]) with ESMTPSA (Nemesis) id 1N6bD0-1p9oVz1y4U-018LiM; Tue, 25 Oct 2022 04:49:21 +0200 From: Michael Heerdegen To: Mattias =?utf-8?Q?Engdeg=C3=A5rd?= Subject: Re: 29.0.50; rx doc: Semantics of RX... In-Reply-To: ("Mattias =?utf-8?Q?Engdeg=C3=A5rd=22's?= message of "Mon, 24 Oct 2022 14:49:25 +0200") References: <3BB74199-7826-41F5-96BA-39CB3EC0E2B7@gmail.com> <87pmeic5lq.fsf@web.de> Date: Tue, 25 Oct 2022 04:49:20 +0200 Message-ID: <87mt9klirz.fsf@web.de> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:4Q7n2+tUpPzKrIV1H5zozImpjCfEpR8qg7iSKWR0w6PzeMFQYSV BKP8R/EzoFvnZtvr/+C4JrdvrtxvyFgLAC1LR2+domV4UjBPQYUxADmRvxyDyHmZ0YR+2fP L2Ob+dbhGlNyxLrfOWsxfRTo9VsG6PIjvPlUESXHgbPGePNdLz5zBPD90MZcPRNO9Sro+3Y DhKmR16uzH0c1rCKOHj3g== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:273WX6PvvFA=;zXCHKn81YAXAOJl0albwtvvTnkm vLmc9LXpUrcF+ZfC1Q8K0mojcPA7N2sMGpPSRuZwEDNvLl5gzC66JeefAQrDXaEwvNkKrVSuv Yl1l7hVAevv1gBXnCR+IJhH9aAwWb0+mOAp4tHBfBtF8cQcyWJDYKq6WaFp4yPt00SzEDYUtT ouSa+ZyNQpSh+GI3uiGM2Ds5FexzcmFWx2j1JsT0nsUR4gnCkcHTdLDfAoyteCLzniF/I8pLK 8YvzMHqxZ94LExcctr8RJX0KjNIymiThuh4Ct/WTvWHi4RZdbToBnrOZ+6XrAyj/FIAjRzGDW zwDKZBhtkJHemrGrA6PBVbFEDT8xbMSMA/bA90F97pYrP0srPwyZ2jZ+XsrouISy8hPeXTyPu eXhBC//NCRCjx8TZ6oaDaMXLAD91F1IJoHzChp8pndcjQ62zwYZb2v4qjdhsYur4k3WeWI/jj 9F7Wgxat1OBS+TLKivgzPgdjiw6AYETg2LtRuo16lcnJ4m5x6p10KbDdqkjPc0ouoXp/eENyv 6XA+fA36jD3DK2R8DeFpuKJcT96qM2guTs18yJjrZz7Mnh1IO2jmhSbrmCoafajPz8s9459u+ EjLreIIoIfDEfVNU4/4aidASiA3AGei8qDQCBAfdt+4jjeQ1fbm/9XQIpW7U+qIw3rNa7tlyW d4394McPyItH1FJgbaMPq/2L9A7v+uSyEvyeZUhygxgY/tH6CT41SWMA9GXQsx5JKRM7/hHK5 Q9vFQrAr5leHr/IQh+tl+/ZLgY8HhpCOjl69Z+o40eh4HDA94X6vh4rLpqLP8dLgNW6blSUFi cnl6sKUZvRQKr7U6A5E2Ie1aU10sCOlb0SppYDzMRedAnuLoNwGwTfPLbY0yGTNdFb+o51Uq2 cEPwKdlW0K83WCH8SxwGjvSUekHPvCtZ7XyftPcq3jBuk0x/2HUae50+rBX/5+C2G0db2zlGi ssTGYg== X-Spam-Score: -0.7 (/) X-Debbugs-Envelope-To: 58727-done Cc: 58727-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: -1.7 (-) Mattias Engdeg=C3=A5rd writes: > > A sentence like "rx forms are defined by their semantics" would help > > to make that clear I think. > > Well, I added a phrase to that effect as well. Thanks - I hope it was not too much. > Thank you for your comments and suggestions! And thank you for the implementation of these! Regards, Michael. ------------=_1666666202-27259-1 Content-Type: message/rfc822 Content-Disposition: inline Content-Transfer-Encoding: 7bit Received: (at submit) by debbugs.gnu.org; 23 Oct 2022 02:32:29 +0000 Received: from localhost ([127.0.0.1]:42692 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1omQmq-000884-Sq for submit@debbugs.gnu.org; Sat, 22 Oct 2022 22:32:29 -0400 Received: from lists.gnu.org ([209.51.188.17]:38086) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1omQmm-00087u-EL for submit@debbugs.gnu.org; Sat, 22 Oct 2022 22:32:27 -0400 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 1omQmm-0005IW-65 for bug-gnu-emacs@gnu.org; Sat, 22 Oct 2022 22:32:24 -0400 Received: from mout.web.de ([212.227.15.3]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1omQmi-0006zV-1M for bug-gnu-emacs@gnu.org; Sat, 22 Oct 2022 22:32:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=s29768273; t=1666492337; bh=r6gBLim2dbFhVgOVWdBJmTyHTJzEdDNvx5AtYdbCwkY=; h=X-UI-Sender-Class:From:To:Subject:Date; b=GJxLxI56GROgpN6eJ3sR071XyQ+bCq8+/X5s/4obuPJmfGy08p63bR/DP30LkYbw9 mCMt1jSLftKzAKXbvvpHn6jJPNmYE+PLYPwiuADXBc4FQZBTUbJA/fKsxDaAdFJ0uY HFDN0nZ7ZY80GojLd/bzbK7KRtkEyLGDwQlCkzG6/Fe9jUy4+EvYTM1/tCtk1hsbOr uxHS5RvGs9VKSZECGZ37cxdQPKLlcUfTmbisKBcGV7671vkq4rMB64RSBbJjEnD0Oh f+pumDeWdCJtxhDGorUZWB2KMI9uUhxVuvmSxkxNM4QtsxqDBrck6wBtqj0HcwCiav 5RsM9crm+3RgQ== X-UI-Sender-Class: 814a7b36-bfc1-4dae-8640-3722d8ec6cd6 Received: from drachen.dragon ([188.105.185.54]) by smtp.web.de (mrweb005 [213.165.67.108]) with ESMTPSA (Nemesis) id 1MQ8Wa-1oQWDB3B56-00MBdg; Sun, 23 Oct 2022 04:32:17 +0200 From: Michael Heerdegen To: bug-gnu-emacs@gnu.org Subject: 29.0.50; rx doc: Semantics of RX... Date: Sun, 23 Oct 2022 04:32:17 +0200 Message-ID: <87tu3v2rta.fsf@web.de> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:nXm9M5LUoQ9PAdzi6QbPGXeA6Y8LM5r6gevVtpukdnq5OplJf5L q7+SFbsGr7Pu2eGqaOquW/sEBPi9hxbGiizptwOmRd6NLwvP7R1Sw8sezmCqltD24Re0ZMA H2wFx/NsN9ff2sZId5+G5oH9ZWrxNSujjAGBrlGv+NTXrjyUqsV7gZhPcRSsg3j/zpUqwiD Byt9E7zJdaMR83zy7Rplg== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:jbm2G1ni24w=;oVsf5UdDWqWb7OmA1fYIYyN7Dlf 1kWq8RJKrfj6T/3xrZH2lWJLUCmFoDvFFGmwG7amBX9UMMdm0JgE5qV1guRuX7FsehGS6QCNk ozsNI1Ta/GMl3KH394rDzw/xVeVLsKNfUoo8R99IPXZT9Lgqka0JuGihGOUh0kwsrrPcElVd+ VqF9upE3mghJY8h8YC2AggKXs/OODoMR3AA5mXt3qN59eI7VZtiUPZ/Kkbi+9w03WZ4eqZk9e DP019C+A65JqhQaY3JZcMXAP0GqGGuM72ZIwCxsaSLMRb0vVqqCjF/VoZxoFy3mRz2mlQ0OcQ 7Bx4hgQIjInX5xxMBEwsEgIS2n04klZ90+0ThIGmYMlgKPxfowd6w7je/gnIouzmbVgwEgBGP RsQ1wKQspO/IBbGiMw8bvMahirO6jdo60ckGD0fczwwx3jR/reJggCZxZf5b2w4CHnUccugYr fxudDeRzPsDDgChnI+KyCvXL/oPAhP+szxLTWq1IYHrfkUL+T9kmUq8z/G5q18tOBbSdeY1ni sHQyovHvkKV6PI956dG8CDlJGKiDF/Sd2nkSpMaAw0eREEI8KV8Y87MwzyX1+2xbHlw38CmSe G7BGfvi+J/OcluOwE8bqOiJ7jo1EdFddQp7TjF8zKJ5NlhX4MwfydCluhh/Ve/U/gdWZsGV6N /QgxPOSCJ3o9c01i5n7+EuWNGj2AuCgyNrug5E2QmdTC8RF3OlDKNMwcosbg3hSb+wwtwkAoL nMKDkzlkN30LdTTaWVVxS78prNKxYye7DXUv3Gvl0QFKR+iSQ4n2Q4cTdMQ884GHApZVfIz1u jzXNu+bQ2mA7sOV7e82Y/ZeEm3rnWNipC4RDZugF+O6Sca5Lwe7grwUL6rxX3kOFkyO6sFwgr mjs4M3X6j/Z/8xKQvfKewUd85jAGk25u3D9jrJM2MLv+cxhEFO0S3bCZmZZFINxdoFjztPDgf pvuVR4wP6o3FcYU1KX7FXKWJuVY= Received-SPF: pass client-ip=212.227.15.3; envelope-from=michael_heerdegen@web.de; helo=mout.web.de X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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_FROM=0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-Spam-Score: -0.7 (/) X-Debbugs-Envelope-To: submit 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: -2.4 (--) Hello, please document the semantics of multiple RXs for the RX repetition operators (and maybe grouping operators, too). The resulting regexps are concatenating like with an implicit `seq'. This is not trivial, though: in stringish regexps the repetition operators are only unary, and different interpretations would make sense for `rx' (implicit `seq', implicit `or'). The docstring of `rx' doesn't tell anything about this. The manual has sentences like | =E2=80=98(zero-or-more RX...)=E2=80=99 | =E2=80=98(0+ RX...)=E2=80=99 | Match the RXs zero or more times. Greedy by default. | Corresponding string regexp: =E2=80=98A*=E2=80=99 (greedy), =E2=80= =98A*?=E2=80=99 (non-greedy) but that suffers from the same problem that the semantics of A are not clear: A =3D=3D (seq RX...) ? Oh, and maybe let's also make more clear that `rx' always cares about implicit grouping when necessary. For example, in (info "(elisp) Rx Constructs") it's not trivial that e.g. in =E2=80=98(seq RX...)=E2=80=99 =E2=80=98(sequence RX...)=E2=80=99 =E2=80=98(: RX...)=E2=80=99 =E2=80=98(and RX...)=E2=80=99 Match the RXs in sequence. Without arguments, the expression matches the empty string. Corresponding string regexp: =E2=80=98AB...=E2=80=99 (subexpressions i= n sequence). `rx' silently adds shy grouping to the result, and the corresponding string regexp in this case is more precisely \(?:AB...\). I think it is enough to mention this implicit grouping feature once, but it is important to spell it out. =20=20 TIA, Michael. ------------=_1666666202-27259-1--