From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 95298C433FE for ; Fri, 4 Nov 2022 16:15:43 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oqzLj-0006B8-1N; Fri, 04 Nov 2022 12:15:19 -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 1oqzLg-0005yI-Bc for qemu-devel@nongnu.org; Fri, 04 Nov 2022 12:15:16 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oqzLd-0000eL-Qu for qemu-devel@nongnu.org; Fri, 04 Nov 2022 12:15:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667578513; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=sJR4fddbZOxcPMgQY405ulC488zF4pzggKXH01czHxA=; b=RwPRs2Aj+ewqFcj6fDdD//eAT7eFbCq4rF976xqsqPb31njvJYPMHzp3z1T6lCqE7dHxkB 5mrOIGAYS0PpDndSELe1yNEAy9DLTBWW4JVog2BFPcOHV7rsTwiR45XdBPQl7Uy15DeRhq f++bn5OrRQgZxgQXJY0H2StgjL+4t8k= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-675-1FWO3MQVMW6y-gIvYp2mAA-1; Fri, 04 Nov 2022 12:15:09 -0400 X-MC-Unique: 1FWO3MQVMW6y-gIvYp2mAA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 41502185A78B; Fri, 4 Nov 2022 16:15:09 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.193.175]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1D4B84EA4C; Fri, 4 Nov 2022 16:15:09 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id EF8C121E6900; Fri, 4 Nov 2022 17:15:06 +0100 (CET) From: Markus Armbruster To: qemu-devel@nongnu.org Cc: jsnow@redhat.com, eblake@redhat.com, michael.roth@amd.com Subject: Re: [PATCH v3 00/30] qapi: Elide redundant has_FOO in generated C References: <20221104160712.3005652-1-armbru@redhat.com> Date: Fri, 04 Nov 2022 17:15:06 +0100 In-Reply-To: <20221104160712.3005652-1-armbru@redhat.com> (Markus Armbruster's message of "Fri, 4 Nov 2022 17:06:42 +0100") Message-ID: <87wn8azofp.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.045, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Qemu-devel" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Markus Armbruster writes: > In QAPI, absent optional members are distinct from any present value. > We thus represent an optional schema member FOO as two C members: a > FOO with the member's type, and a bool has_FOO. Likewise for function > arguments. > > However, the has_FOO is actually redundant for a pointer-valued FOO, > which can be null only when has_FOO is false, i.e. has_FOO == !!FOO. > Except for arrays, where we a null FOO can also be a present empty > array. > > The redundant has_FOO are a nuisance to work with. Improve the > generator to elide them. > > PATCH 01+02 are trivial documentation cleanups. > > PATCH 03 tweaks an example in documentation so it'll show the change. > > PATCH 04 improves the code generator, but nerfs the change for the > schema modules where handwritten code needs to be updated. > > PATCH 05-07,10-29 un-nerf in reviewable chunks. Their commit messages > refer back to PATCH 04 for an explanation of the transformation. > Please read that first. Note that these patches combine the > mechanical transformation with obvious, local follow-up > simplifications. If you want them separate for easier review, let me > know. > > PATCH 08+09 clean up in preparation for PATCH 10. > > PATCH 28 drops the nerfing code. PATCH 30, of course.