From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Taylan Kammer Newsgroups: gmane.lisp.guile.user Subject: Re: Equality and hashing for new datatypes Date: Fri, 23 Jun 2023 09:09:20 +0200 Message-ID: <5eac5cec-c7d1-70a5-ffde-ae58c4e36a1c@gmail.com> References: <3759578.e9J7NaK4W3@bastet> <01fa3142-02d8-9bb0-9dfd-5b233aa57bbf@gmail.com> <2803364.tdWV9SEqCh@bastet> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="12601"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 To: Philip McGrath , guile-user Original-X-From: guile-user-bounces+guile-user=m.gmane-mx.org@gnu.org Fri Jun 23 09:10:08 2023 Return-path: Envelope-to: guile-user@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 1qCavn-00037v-Rc for guile-user@m.gmane-mx.org; Fri, 23 Jun 2023 09:10:07 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qCavE-0002VD-Kl; Fri, 23 Jun 2023 03:09:32 -0400 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 1qCavA-0002Uj-LY for guile-user@gnu.org; Fri, 23 Jun 2023 03:09:30 -0400 Original-Received: from mail-ej1-x62d.google.com ([2a00:1450:4864:20::62d]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qCav8-0007wW-Qk for guile-user@gnu.org; Fri, 23 Jun 2023 03:09:28 -0400 Original-Received: by mail-ej1-x62d.google.com with SMTP id a640c23a62f3a-98bcc5338d8so27736466b.1 for ; Fri, 23 Jun 2023 00:09:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1687504163; x=1690096163; h=content-transfer-encoding:in-reply-to:from:content-language :references:to:subject:user-agent:mime-version:date:message-id:from :to:cc:subject:date:message-id:reply-to; bh=mEwpX2h2ASsiAQoU2ELLO9v6J1GNbt+vYgU/2Av9Xho=; b=gHI/SX/Cf/m365VSxXQgcDzgwNQzdCg3cwRKt2+A2mI0DDhZLV/kDZR2yiThLCAfeR y//StK6NqvIWccAdLYCG7/ssFTN2I31/t+kkzmE55Ee2vi6x/zG9j41yPrx4YxuopHEU 5qLcLO0cDqpYvcVWW7fXzOplyj74lcukIUiyt2vfuUs+g8ASo3nFVeqfhof1niNvNzo5 yYGWruJ3wzJlPquClXlWWbhNb7Iibus9sSDiElQUaZODAGlKjxJfIp+gck8dWMmV8WBr y2ediomyw3KDdM9GgmMrJUcHG6s6373bgZUXKWc/rTFqXc7E3ZdQJmJdMftvHUZoDTyq 3d4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687504163; x=1690096163; h=content-transfer-encoding:in-reply-to:from:content-language :references:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=mEwpX2h2ASsiAQoU2ELLO9v6J1GNbt+vYgU/2Av9Xho=; b=C/gYYkEoVXzHMIiGnWkKa0YiHuL8Z56giDSUiHpybFHrHWYFuX+NuX9/XRpvXl+/0p 6abbbN6PMSvgkRPYr6ragbsTDfT4WttpwBc5/koSST5/uay7DUEWIUKFql3b6qyobAA2 T9UN3jJNThUkqjPufBRp9BiSJmJm5y2IaSc539h5IFF8/U58ShCGuXdd4DJ48R3CVABj EvPa9gIIyxWEt99zFZ9/NTnsX3MqD/cL0qNnF5tmzXtoBFr6rLUcJoJcDJioY6otBks7 TYoxmAhf0XdbStsLPIeRuH9Q+Kx4wBxGy7i3vkABJKnjpC1P/KoJkmzKdnrPq+le2wFX 6kbQ== X-Gm-Message-State: AC+VfDysuChM2xu1cRuEDKL33pMpMypMhi1kLFbHdSFmxRhODKJcTyjg w6Vl+LhvwsHKpVm0GNw6sgRhf/l2OKc= X-Google-Smtp-Source: ACHHUZ4FrwMdj9o7e2XmYaXviaNtXKXaJfKNmLmmq3IiqPLEoDhmFHmbRoJhZzND/z7h030KyIU8qg== X-Received: by 2002:a17:906:53cd:b0:98d:81c7:f01a with SMTP id p13-20020a17090653cd00b0098d81c7f01amr689683ejo.62.1687504163298; Fri, 23 Jun 2023 00:09:23 -0700 (PDT) Original-Received: from [192.168.178.20] (ip-109-090-125-150.um36.pools.vodafone-ip.de. [109.90.125.150]) by smtp.gmail.com with ESMTPSA id bf18-20020a0564021a5200b0051be86ff767sm1915307edb.70.2023.06.23.00.09.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 23 Jun 2023 00:09:22 -0700 (PDT) Content-Language: en-US In-Reply-To: <2803364.tdWV9SEqCh@bastet> Received-SPF: pass client-ip=2a00:1450:4864:20::62d; envelope-from=taylan.kammer@gmail.com; helo=mail-ej1-x62d.google.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 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, NICE_REPLY_A=-0.09, RCVD_IN_DNSWL_NONE=-0.0001, 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: guile-user@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: General Guile related discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guile-user-bounces+guile-user=m.gmane-mx.org@gnu.org Original-Sender: guile-user-bounces+guile-user=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.lisp.guile.user:19060 Archived-At: On 23.06.2023 00:45, Philip McGrath wrote: > On Thursday, June 22, 2023 7:33:06 AM EDT Taylan Kammer wrote: >> On 22.06.2023 00:25, Philip McGrath wrote: >>> Hi, >>> >>> What is the recommended way for a library to customize `equal?` and >>> `equal?` -based hashing for new datatypes it defines? >>> >>> I know from [1] that `equal?` can be customized using GOOPS; however, some >>> projects do not use GOOPS (e.g. [2]), so it would seem more friendly for a >>> generic library to avoid it. Also, it is not clear if the same mechanism >>> is >>> even an option for customizing `equal-hash` to match `equal?`. >>> >>> I'm looking for something like Racket's `gen:equal+hash` [3] or Chez >>> Scheme's `record-equal-procedure` and `record-hash-procedure` [4]. >>> >>> This came up while I was working on a portable version of the immutable >>> hash-table implementations from Racket-on-Chez. >>> >>> -Philip >>> >>> [1]: >>> https://www.gnu.org/software/guile/manual/html_node/GOOPS-Object-Miscella >>> ny.html [2]: >>> https://lists.gnu.org/archive/html/info-gnu/2023-05/msg00005.html [3]: >>> https://docs.racket-lang.org/reference/Equality.html#%28part._.Implementi >>> ng_.Equality_for_.Custom_.Types%29 [4]: >>> https://cisco.github.io/ChezScheme/csug9.5/objects.html#./objects:h14 >> Hi Philip, >> >> You can use SRFI 69 hash tables in Guile. This library offers a way to >> specify the equality and hash procedures that should be used by a hash >> table, e.g.: >> >> [...] >> >> Note that this doesn't affect the behavior of the standard 'equal?' >> procedure, it only affects the SRFI 69 hash table operations on the created >> hash table. >> >> I currently don't remember whether Guile's own non-portable hash table >> library supports the same feature. It probably does in some way. >> > > Thanks, but this is the opposite of what I want to do. The library I'm porting > already supports creating tables with custom equality and hashing functions. > What I'm trying to do is make the standard `equal?` procedure recognize when > two of my table values are semantically the same even if internal > implementation details differ. > > (Note also that SRFI 69 and other libraries provide *mutable* hash tables. The > Racket-on-Chez library I'm porting provides immutable hash tables, more > properly Hash Array Mapped Tries, as made famous by Clojure.) > > -Philip Ah, apologies then. As far as I know, there's no other way to do that in Guile than with GOOPS, which you've already mentioned. In standard Scheme there's no way to do it at all. I don't think there's even an SRFI for it (I just searched a bit, out of curiosity, couldn't find anything). -- Taylan