From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Philip Kaludercic Newsgroups: gmane.emacs.devel Subject: Re: Instead of pcase Date: Thu, 16 Nov 2023 18:47:48 +0000 Message-ID: <87zfzdcz6z.fsf@posteo.net> References: <87fs169mjj.fsf@posteo.net> <093f11a1-57c2-5e56-d39b-26fef1c67cbb@gutov.dev> <25942.25061.217864.329049@retriever.mtv.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="36735"; mail-complaints-to="usenet@ciao.gmane.io" Cc: dmitry@gutov.dev, rms@gnu.org, emacs-devel@gnu.org To: "T.V Raman" Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Thu Nov 16 19:48:47 2023 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 1r3hPy-0009JH-77 for ged-emacs-devel@m.gmane-mx.org; Thu, 16 Nov 2023 19:48:46 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1r3hPF-0001yJ-1b; Thu, 16 Nov 2023 13:48:02 -0500 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 1r3hPB-0001xs-VC for emacs-devel@gnu.org; Thu, 16 Nov 2023 13:47:58 -0500 Original-Received: from mout01.posteo.de ([185.67.36.65]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r3hP9-0004EY-2j for emacs-devel@gnu.org; Thu, 16 Nov 2023 13:47:57 -0500 Original-Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id 7F8D9240029 for ; Thu, 16 Nov 2023 19:47:49 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.net; s=2017; t=1700160469; bh=YtaOFshO0PmayK3QTVPMUcutHmHjp6gM7FeyXmOz/dg=; h=From:To:Cc:Subject:Autocrypt:Date:Message-ID:MIME-Version: Content-Transfer-Encoding:From; b=QqdPVb04E7yH6vkV5TaZyVLFnpM+fNsG8KVu43BVmw1iRe5RwIrPVGyMz6JLn4Ine wuD+mJ9vJGle6XR0p8IqYaONgdLgwTJtCZTYqS/WmTjChIFPNDJNI6IbiRnqowMia7 B5szGdT8qcDra0tsVo7F6bWsBU0TfPGm4xyRL16/yec4MZJG01AkkPUryvRv3YvTyT lYSYlRSn6DQVAE63ReHgpketJ13iQpQwtlzf1I1jBcOAx8R4FNgsvKRvUOAU7uYPn1 U8X1k4XHowNQ1yA7IG8BwyVLVrGh9LL+0mLIQYE95Mp9owS/OmcY+24d+Tc28QJUdi WfpZ5OvT3LYYw== Original-Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4SWTYc486dz6v2S; Thu, 16 Nov 2023 19:47:48 +0100 (CET) In-Reply-To: <25942.25061.217864.329049@retriever.mtv.corp.google.com> (T. 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Raman's message of "Thu, 16 Nov 2023 10:39:33 -0800") Autocrypt: addr=philipk@posteo.net; keydata= mDMEZBBQQhYJKwYBBAHaRw8BAQdAHJuofBrfqFh12uQu0Yi7mrl525F28eTmwUDflFNmdui0QlBo aWxpcCBLYWx1ZGVyY2ljIChnZW5lcmF0ZWQgYnkgYXV0b2NyeXB0LmVsKSA8cGhpbGlwa0Bwb3N0 ZW8ubmV0PoiWBBMWCAA+FiEEDg7HY17ghYlni8XN8xYDWXahwukFAmQQUEICGwMFCQHhM4AFCwkI BwIGFQoJCAsCBBYCAwECHgECF4AACgkQ8xYDWXahwulikAEA77hloUiSrXgFkUVJhlKBpLCHUjA0 mWZ9j9w5d08+jVwBAK6c4iGP7j+/PhbkxaEKa4V3MzIl7zJkcNNjHCXmvFcEuDgEZBBQQhIKKwYB BAGXVQEFAQEHQI5NLiLRjZy3OfSt1dhCmFyn+fN/QKELUYQetiaoe+MMAwEIB4h+BBgWCAAmFiEE Dg7HY17ghYlni8XN8xYDWXahwukFAmQQUEICGwwFCQHhM4AACgkQ8xYDWXahwukm+wEA8cml4JpK NeAu65rg+auKrPOP6TP/4YWRCTIvuYDm0joBALw98AMz7/qMHvSCeU/hw9PL6u6R2EScxtpKnWof z4oM Received-SPF: pass client-ip=185.67.36.65; envelope-from=philipk@posteo.net; helo=mout01.posteo.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 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, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 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-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:312828 Archived-At: "T.V Raman" writes: > when-let let-alist etc have worked well for me. > > What threw me with pcase is there are lots of special chars in that > particular example whose meaning I dont know, and looking those up and > understanding their use at the same time was what chased me away Taking the concrete example you mentioned,=20 (pcase res (`(,_ . ,(and (pred functionp) f)) (funcall f)) (`(,hookfun . (,start ,end ,collection . ,plist)) the unknown or unfamiliar characters are "`" and ",". The (dynamic) pcase documentation string is pretty straightforward in explaining what it does, or can you recall what confused you?: --8<---------------cut here---------------start------------->8--- -- `QPAT Backquote-style pcase patterns: `QPAT QPAT can take the following forms: (QPAT1 . QPAT2) matches if QPAT1 matches the car and QPAT2 the cdr. [QPAT1 QPAT2..QPATn] matches a vector of length n and QPAT1..QPATn match its 0..(n-1)th elements, respectively. ,PAT matches if the =E2=80=98pcase=E2=80=99 pattern PAT = matches. SYMBOL matches if EXPVAL is =E2=80=98equal=E2=80=99 to SYM= BOL. KEYWORD likewise for KEYWORD. NUMBER likewise for NUMBER. STRING likewise for STRING. The list or vector QPAT is a template. The predicate formed by a backquote-style pattern is a combination of those formed by any sub-patterns, wrapped in a top-level condition: EXPVAL must be "congruent" with the template. For example: `(technical ,forum) --8<---------------cut here---------------end--------------->8--- Or if you mean "_", then --8<---------------cut here---------------start------------->8--- PATTERN can take one of the forms: _ matches anything. --8<---------------cut here---------------end--------------->8--- which is familiar to people coming from functional languages, but even Elisp uses underscores to denote unused variables.