From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Michael Heerdegen Newsgroups: gmane.emacs.devel Subject: Re: Make peg.el a built-in library? Date: Sat, 09 Oct 2021 03:31:03 +0200 Message-ID: <87a6jjc7c8.fsf@web.de> References: <875yvtbbn3.fsf@ericabrahamsen.net> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="31074"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) Cc: Stefan Monnier , emacs-devel@gnu.org To: Eric Abrahamsen Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Oct 09 03:32:00 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 1mZ1DU-0007tQ-RN for ged-emacs-devel@m.gmane-mx.org; Sat, 09 Oct 2021 03:32:00 +0200 Original-Received: from localhost ([::1]:35702 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mZ1DS-0004pn-SX for ged-emacs-devel@m.gmane-mx.org; Fri, 08 Oct 2021 21:31:58 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:59516) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mZ1Ct-0004BB-KU for emacs-devel@gnu.org; Fri, 08 Oct 2021 21:31:23 -0400 Original-Received: from mout.web.de ([212.227.15.4]:48531) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mZ1Cr-0000Pz-M3 for emacs-devel@gnu.org; Fri, 08 Oct 2021 21:31:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1633743065; bh=mPcOaLdNbkt2hQOy6dvrBM1Py/jsN6EYiARO3uhkQYk=; h=X-UI-Sender-Class:From:To:Cc:Subject:References:Date:In-Reply-To; b=NKHr4MK6BHEocze6cFTh8AwtV4waSq7br8cyJYhMzSOST8rsXJ4ygv7Lp47voCigh VXucQsZLvnDnXAynhX7mhF5daxCSdba8UUZDtuNKINIf3FXX0/0cVaFAFNBHU3SD1c VlhhxV1ufsTn353KeJJkysSCb8QjciG+HE2Txvj4= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Original-Received: from drachen.dragon ([92.208.225.87]) by smtp.web.de (mrweb001 [213.165.67.108]) with ESMTPSA (Nemesis) id 0MQNzw-1mBpUS3RbY-00TneD; Sat, 09 Oct 2021 03:31:04 +0200 In-Reply-To: <875yvtbbn3.fsf@ericabrahamsen.net> (Eric Abrahamsen's message of "Wed, 25 Aug 2021 11:52:00 -0700") X-Provags-ID: V03:K1:PG7kGmxTLKwCM9eYHYbKkNqYJ6wVvyNrUmHLhk1Gv+S4knn9wcI Bjk2HOK2XbVNCZMfZQyZ6aRGcFEH0sgwi8L1tEWE58WsZHPiLydNRgmvUixks1tOcaCs8jd sTk8oK5lcfoX7FwM1LeJdaD1qEWqgH1t/EUgHdoQePkocaHQddtc2gpXZgSvu4V+QgzT6bl BzrgYgiz5/EcQ384xNnjQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:KTYbBNk3YZU=:bwZFXeo5suBdwKkE7GiHts PsQFlkL0JAqlU5qDSqrRAzu2EMgd2HUn5BcjSCsktphWLcD6ZfslK0E0F+FYV3wyg1yOlYixQ yEHMz9J5NrcbT4qCAd6s5nj+cTAeSLq8G8CnBqyIH6hJXOCBQLnUkhbRxO5TTZICXEI/rVXlt FwyxZlzXmOw4bNpC2yrIahJ2Rn9K9yJEfpdjZ8NTL0fyfBGUe+cAs1pFbgC5ZOdzZlchTfIpb jf8+MA4R66S1RXm71qTrwH7BO1Zn7yB/HjadMiECmIc8CSzMDEOR7hYgtS09mCIUX9x9dnpOu cyrRuHrMTkOuZ1NKxwJ97TVFFbJk5oQeSlaZJd+VmBPZ/k+f0n+FxZRSAU7tQ2pzrvlkdEASq tLG81JtlfSJGgwAvOCLnatvdBzVE5ihwn5LEzfuhsYNq+qU/Reazk7LHAAhmCcJruEBk8D1kT Dve2K8By7xsz/zYmrYbW2DfbjMnMOoopOBjSWCS/39xCacW+yc/J+rl+uptPQBOWjDANQOE3F YMNrNpBpA8hJM+nE2XAQ1ZvheiviePgQ+ctis+4jF2U9kli0A0pwEBW/8aGsBOxhXSj6qYhlQ 93UjGmKKI6/RWvEriim07jWmX0Vg0UbIukvZ5d38TWvyaqlk3ppGt0vtlaApgudRg8xa/V38U jeemKXp5C/1zHff4vZc/CI/AS4bJFI4vVZ5IWqHePfcQOxdOcq56NR1nIqZeXTFSyTKfiiVb+ LWBLL/kEEgW15jnRA6Y6a5ZNSZVFY9NSymkqqDgomlnSOc53Q+xFsiI+cNzBE9+eLdfMb3Vm Received-SPF: pass client-ip=212.227.15.4; 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-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:276582 Archived-At: Eric Abrahamsen writes: > Hi all, > > In my on-again-off-again quest to not have to write text parsers myself, > I was pointed towards the PEG library (in ELPA), which does pretty much > exactly what I want (Parsing Expression Grammars). I like the idea, and I have some remarks: (1) Can we improve the introduction in the file header a bit? I would add a link to the wikipedia page: https://en.wikipedia.org/wiki/Parsing_expression_grammar it explains some background. And: one example could contain the (non-standard if you only know regexps, but very educative) solution to the problem: "how do you jump over arbitrary text preceding a match?" (the answer seems to be: "use `or' and recursion", at least this is what I found out by myself after a while). (2) Would (replace E RPL) not be much more useful if it would be allowed to pop from the stack? Something like (replace E [VAR...] -- REPL) where REPL could use the VAR bindings? Background is of course that a replacement may depend on intermediate parsing results. (3) `(_ --) seems to produce an "Empty let body" compiler warning - can we silence it? (4) How hard would it be to parse regexps (or translate `rx' forms) into an equivalent peg? (5) We need to add a Game-like tutorial to PEGs called Peg-Man. Ok, that one was only a joke. WDYT? Thanks, Michael.