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 X-Spam-Level: X-Spam-Status: No, score=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F614C433E0 for ; Thu, 4 Feb 2021 16:36:24 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 0D94064F4E for ; Thu, 4 Feb 2021 16:36:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0D94064F4E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:53074 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l7hcE-0003dJ-R2 for qemu-devel@archiver.kernel.org; Thu, 04 Feb 2021 11:36:22 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:37026) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l7hV6-0004uT-T3 for qemu-devel@nongnu.org; Thu, 04 Feb 2021 11:29:01 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:60330) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l7hV3-0007YF-IL for qemu-devel@nongnu.org; Thu, 04 Feb 2021 11:29:00 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612456136; 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=PIbJeu3OMGSHYaHLB9jzR8Kw5PhMGKIJJuG12OG/S6A=; b=Hfjj40Z5SIvps6Bfj/YurUGHWriqD1GXxAplTk6z6c/q1kqhHqhcxHolmDIHCsBhVb2qGT Nmh/A7k6N6ICIQJKTsFCfzsj+TNtJfvN22sZBAKV/jytkAlUhqtefnCDasnPTSylqWX6tH aR9cW8OjTCVqpmDhi71eSs/ACrsOQzI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-473-ZBoh4LVHNY6rgz8WcaOO-A-1; Thu, 04 Feb 2021 11:28:52 -0500 X-MC-Unique: ZBoh4LVHNY6rgz8WcaOO-A-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id ECCC1A0BD9; Thu, 4 Feb 2021 16:28:51 +0000 (UTC) Received: from localhost (ovpn-3-197.rdu2.redhat.com [10.22.3.197]) by smtp.corp.redhat.com (Postfix) with ESMTP id AB12110016FA; Thu, 4 Feb 2021 16:28:48 +0000 (UTC) Date: Thu, 4 Feb 2021 11:28:47 -0500 From: Eduardo Habkost To: Markus Armbruster Subject: Re: [PATCH v4 08/14] qapi/introspect.py: create a typed 'Annotated' data strutcure Message-ID: <20210204162847.GD126021@habkost.net> References: <20210202174651.2274166-1-jsnow@redhat.com> <20210202174651.2274166-9-jsnow@redhat.com> <878s85tdh3.fsf@dusky.pond.sub.org> <20210203215026.GB126021@habkost.net> <87a6sjdet2.fsf@dusky.pond.sub.org> MIME-Version: 1.0 In-Reply-To: <87a6sjdet2.fsf@dusky.pond.sub.org> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=ehabkost@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=ehabkost@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=-0.351, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Michael Roth , John Snow , qemu-devel@nongnu.org, Cleber Rosa Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Feb 04, 2021 at 04:37:45PM +0100, Markus Armbruster wrote: > Eduardo Habkost writes: > > > On Wed, Feb 03, 2021 at 03:47:36PM +0100, Markus Armbruster wrote: > >> John Snow writes: > >> > >> > Presently, we use a tuple to attach a dict containing annotations > >> > (comments and compile-time conditionals) to a tree node. This is > >> > undesirable because dicts are difficult to strongly type; promoting it > >> > to a real class allows us to name the values and types of the > >> > annotations we are expecting. > >> > > >> > In terms of typing, the Annotated type serves as a generic container > >> > where the annotated node's type is preserved, allowing for greater > >> > specificity than we'd be able to provide without a generic. > >> > > >> > Signed-off-by: John Snow > > [...] > >> > +class Annotated(Generic[_NodeT]): > >> > + """ > >> > + Annotated generally contains a SchemaInfo-like type (as a dict), > >> > + But it also used to wrap comments/ifconds around scalar leaf values, > >> > + for the benefit of features and enums. > >> > + """ > >> > + # Remove after 3.7 adds @dataclass: > >> > >> Make this > >> > >> # TODO Remove after Python 3.7 ... > >> > >> to give us a fighting chance to remember. > >> > >> > + # pylint: disable=too-few-public-methods > >> > + def __init__(self, value: _NodeT, ifcond: Iterable[str], > >> > + comment: Optional[str] = None): > >> > >> Why not simply value: _value? > > > > Example: > > x = C(1) > > y: C[int] > > y = C('x') # mistake > > > > Declaring value as _NodeT does: > > - Make the inferred type of x be Annotated[int]. > > - Catch the mistake above. > > I smell overengineering. I may well be wrong. To me it's just regular and idiomatic use of Generic. > > Without doubt, there are uses for using the type system for keeping > SomeGenericType[SomeType] and SomeGenericType[AnotherType] apart. > > But what do we gain by keeping the Annotated[T] for the possible T > apart? I understand this as (valid) criticism of the use of Generic. If we don't want to make Generic[T1] and Generic[T2] be different types, there's no point in using Generic at all. > > _tree_to_qlit() doesn't care: it peels off the wrapper holding ifcond > and comment, and recurses for the JSON so wrapped. Regardless of what > was wrapped, i.e. what kind of T we got. > > Heck, it works just fine even if you wrap your JSON multiple times. It > doesn't give a hoot whether that makes sense. Making sense is the > caller's business. > > So what does care? > > Or am I simply confused? Those are valid questions. Maybe using Generic will be useful in the future, but maybe we don't need it right now. Personally, I don't care either way. I just wish this small choice don't became another obstacle for doing useful work. > > > PS: As far as I can tell, _tree_to_qlit() doesn't give a hoot whether a > dictionary's values are wrapped, either. -- Eduardo