From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: thunk.el: Document that thunk-force == funcall? Date: Tue, 17 Nov 2020 16:51:22 -0500 Message-ID: References: <871rgs3tdx.fsf@web.de> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="8552"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Cc: Nicolas Petton , Emacs Development To: Michael Heerdegen Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue Nov 17 22:52:54 2020 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 1kf8uE-0001L0-IW for ged-emacs-devel@m.gmane-mx.org; Tue, 17 Nov 2020 22:52:54 +0100 Original-Received: from localhost ([::1]:55736 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kf8tU-0000NK-Sr for ged-emacs-devel@m.gmane-mx.org; Tue, 17 Nov 2020 16:52:08 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:41910) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kf8sr-0007wK-FE for emacs-devel@gnu.org; Tue, 17 Nov 2020 16:51:29 -0500 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:35157) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kf8sp-0008Sh-5m for emacs-devel@gnu.org; Tue, 17 Nov 2020 16:51:28 -0500 Original-Received: from pmg2.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 2446380CFB; Tue, 17 Nov 2020 16:51:25 -0500 (EST) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 94F66806F7; Tue, 17 Nov 2020 16:51:23 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1605649883; bh=a7p7FvpP3vsGse00QjKLMpohBBD4kq9roFxBt4S0d4o=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=TRJXds25RtnGTY6iP5MXliTmaU3E5ZXDvPvB3WD2c5RFlFDBNnKPqScbtRsi9dUAJ np2aQc1ncAUT373axJyMIYzb0dGcLR+CkHkDeEjOGW3Pcqydscgz1BB7/t+OBig9s5 9iJ6s6dbNYTFmO630vhcj5jQBQDVVWuVdFjEEW0r+XnJx5T5/9W25S5pP1Q5fnyAel RjtU2qAPyYcU8724zwEiwCpk3Ljbu9qVfxziD2sk5uqfm6LKNU+svBvPkzPhPaZH6H DbNNitNp/jg55TdKdsi5i+tFkP7Yp1aQAv7bygWsLn8s33X0erzqp0zG+5IgxICNNE x9sqJ6rxtzQsg== Original-Received: from alfajor (unknown [157.52.9.240]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 1BED41202CD; Tue, 17 Nov 2020 16:51:23 -0500 (EST) In-Reply-To: <871rgs3tdx.fsf@web.de> (Michael Heerdegen's message of "Tue, 17 Nov 2020 16:17:14 +0100") Received-SPF: pass client-ip=132.204.25.50; envelope-from=monnier@iro.umontreal.ca; helo=mailscanner.iro.umontreal.ca X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/17 16:51:25 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, 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:259319 Archived-At: Michael Heerdegen [2020-11-17 16:17:14] wrote: > The background: because thunks are functions, one is allowed (and it is > useful) to directly pass them to higher order functions e.g. as a test > predicate, or bind them using `cl-flet', or `cl-letf' to a > `symbol-function' place. Currently, the official solution would require > to use a lambda wrapper. I like the idea that we could replace the current representation with something more like a `defstruct`, so I'm on the side of "don't document that thunks *are* functions", but it's not a very strong opinion. In any case even without documenting them to be functions, we could provide (defalias 'thunk-function #'identity) to avoid the wasteful use of a lambda wrapper. > I have encountered this requirement several times (and using `thunk-let' > was not always the solution) - thus my question. [...] > Say the code loops over a list of files or so (not known at think time). > The thunk could "contain" a test that might take long (e.g. something > that might need to look at the file's contents) but the result is > interesting only sometimes, depending on the result of other tests (also > not known at think time). [ That's still pretty hypothetical. ] I'd be curious to see concrete examples, to get a better idea of the tradeoffs. Stefan