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 6DF23C636CC for ; Sat, 11 Feb 2023 06:42:54 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pQjaq-0006q2-Cr; Sat, 11 Feb 2023 01:42:40 -0500 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 1pQjag-0006oZ-GC for qemu-devel@nongnu.org; Sat, 11 Feb 2023 01:42:30 -0500 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 1pQjae-0002kW-FQ for qemu-devel@nongnu.org; Sat, 11 Feb 2023 01:42:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1676097747; 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=nWfOV2VxReqM+tw8V12dOJBWZGOoT5SU6M8niNKNcO8=; b=L3mA9Po/CN7an93N8KwcAXQhEOPtc6OM8cqTNLH6r8aumj+494PBoc0QDKZMAdyggWPksH CPbJN+UqXZmp0gUg2fjWBWKJg6NaeGcNOaBaXlqKYrrMdIoRH/pZEyiwMq6koz2UuYpul9 vB9Y7bb+QpkwPZcGt5/JBeLn/b5ukJA= 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-575-vk_2dfJvOhmmpGIuV53p5Q-1; Sat, 11 Feb 2023 01:42:23 -0500 X-MC-Unique: vk_2dfJvOhmmpGIuV53p5Q-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 7760A101A52E; Sat, 11 Feb 2023 06:42:23 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.193.101]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4EF4C18EC6; Sat, 11 Feb 2023 06:42:23 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 3A71C21E6A1F; Sat, 11 Feb 2023 07:42:22 +0100 (CET) From: Markus Armbruster To: John Snow Cc: qemu-devel@nongnu.org, Michael Roth , Markus Armbruster Subject: Re: [PATCH v3 7/7] qapi: remove JSON value FIXME References: <20230209184758.1017863-1-jsnow@redhat.com> <20230209184758.1017863-8-jsnow@redhat.com> Date: Sat, 11 Feb 2023 07:42:22 +0100 In-Reply-To: <20230209184758.1017863-8-jsnow@redhat.com> (John Snow's message of "Thu, 9 Feb 2023 13:47:58 -0500") Message-ID: <87pmag4sa9.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (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: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org John Snow writes: > With the two major JSON-ish type hierarchies clarified for distinct > purposes; QAPIExpression for parsed expressions and JSONValue for The comment you remove talks about _ExprValue, not QAPIExpression. > introspection data, remove this FIXME as no longer an action item. > > In theory, it may be possible to define a completely agnostic > one-size-fits-all JSON type hierarchy that any other user could borrow - > in practice, it's tough to wrangle the differences between invariant, > covariant and contravariant types: input and output parameters demand > different properties of such a structure. As such, it's simply more > trouble than it's worth. I think there's a weightier counter-argument struggling to get out. As I explained under v2's cover letter, the two types represent things that are only superficially similar. _ExprValue is the obvious stupid abstract syntax tree for the QAPI schema language, with str and bool leaves (QAPI doesn't support floating-point numbers), OrderedDict and list inner nodes. It is used for parser output. QAPIExpression augments _ExprValue, adding a QAPISourceInfo (identifying the expression's source) and a QAPIDoc (the expressions documentation). It is used to represent QAPI top-level expressions. JSONValue is an annotated JSON abstract syntax tree. QAPIExpression and _ExprValue are related to it only insofar as the QAPI schema language is (rather loosely) patterned after JSON. Moreover, the two ASTs serve different purposes. QAPIExpression and _ExprValue represent *input*: they are produced by a parser and consumed by a semantic analyzer. JSONValue represents *output*: it is produced within a backend so we can separate the JSON text formatting aspect. Consolidating these two ASTs makes no sense. Suggest to work this argument into your commit message. > So, declare this "done enough for now". Agree. > Signed-off-by: John Snow > --- > scripts/qapi/parser.py | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py > index c165bd3912c..b5afdd703e7 100644 > --- a/scripts/qapi/parser.py > +++ b/scripts/qapi/parser.py > @@ -42,10 +42,6 @@ > _ExprValue = Union[List[object], Dict[str, object], str, bool] > > > -# FIXME: Consolidate and centralize definitions for _ExprValue and > -# JSONValue; currently scattered across several modules. > - > - > # 3.6 workaround: can be removed when Python 3.7+ is our required version. > if TYPE_CHECKING: > _UserDict = UserDict[str, object]