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=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 10CFDC433B4 for ; Sun, 25 Apr 2021 12:33:45 +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 75D4C6120C for ; Sun, 25 Apr 2021 12:33:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 75D4C6120C 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]:49286 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ladxH-0001f1-Cz for qemu-devel@archiver.kernel.org; Sun, 25 Apr 2021 08:33:43 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39878) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ladvx-0000mv-NQ for qemu-devel@nongnu.org; Sun, 25 Apr 2021 08:32:21 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:26090) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ladvs-0006GF-8B for qemu-devel@nongnu.org; Sun, 25 Apr 2021 08:32:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619353934; 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=bmPekcGZT0PzWmYNm/NF/Hwu9E7GFFyAi48yWKuEdrc=; b=YvLlfBvTsQx0MyVSGk+EIwKXx5aQgE36tumwN06mhu+sieUucRJQxuBO1VC09vn9ER5Ts9 /nW9E9iz4qQGOFUL/nzBTj+YDD0Ozd1CLuWTB2ebH8GTyVa/i1Imj84laIxMAl/CwOPMOD jjc4aX0MPmOPcvikYCmvwijs805GK7I= 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-590-Tz_9aEq5O5GlEGHlq3H8aw-1; Sun, 25 Apr 2021 08:32:12 -0400 X-MC-Unique: Tz_9aEq5O5GlEGHlq3H8aw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 88AEA5132; Sun, 25 Apr 2021 12:32:11 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-114-17.ams2.redhat.com [10.36.114.17]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 632251837F; Sun, 25 Apr 2021 12:32:08 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id E7150113525D; Sun, 25 Apr 2021 14:32:06 +0200 (CEST) From: Markus Armbruster To: John Snow Subject: Re: [PATCH 11/22] qapi/parser: Rework _check_pragma_list_of_str as a TypeGuard References: <20210422030720.3685766-1-jsnow@redhat.com> <20210422030720.3685766-12-jsnow@redhat.com> Date: Sun, 25 Apr 2021 14:32:06 +0200 In-Reply-To: <20210422030720.3685766-12-jsnow@redhat.com> (John Snow's message of "Wed, 21 Apr 2021 23:07:09 -0400") Message-ID: <871ray7dfd.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=armbru@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.219, 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_H4=-0.01, RCVD_IN_MSPIKE_WL=-0.01, 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 , qemu-devel@nongnu.org, Eduardo Habkost , Cleber Rosa Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" John Snow writes: > TypeGuards wont exist in Python proper until 3.10. Ah well. We can hack > up our own by declaring this function to return the type we claim it > checks for and using this to safely downcast object -> List[str]. > > In so doing, I bring this function in-line under _pragma so it can use > the 'info' object in its closure. Having done this, _pragma also now > no longer needs to take a 'self' parameter, so drop it. > > Rename it to just _check(), to help us out with the line-length -- and > now that it's contained within _pragma, it is contextually easier to see > how it's used anyway -- especially with types. > > Signed-off-by: John Snow > > --- > > I left (name, value) as args to avoid creating a fully magic "macro", > though, I thought this was too weird: > > info.pragma.foobar = _check() > > and it looked more reasonable as: > > info.pragma.foobar = _check(name, value) > > Signed-off-by: John Snow > --- > scripts/qapi/parser.py | 26 +++++++++++++------------- > 1 file changed, 13 insertions(+), 13 deletions(-) > > diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py > index 16fd36f8391..d02a134aae9 100644 > --- a/scripts/qapi/parser.py > +++ b/scripts/qapi/parser.py > @@ -17,6 +17,7 @@ > from collections import OrderedDict > import os > import re > +from typing import List > > from .common import match_nofail > from .error import QAPISemError, QAPISourceError > @@ -151,28 +152,27 @@ def _include(include, info, incl_fname, previously_included): > ) from err > > @staticmethod > - def _check_pragma_list_of_str(name, value, info): > - if (not isinstance(value, list) > - or any([not isinstance(elt, str) for elt in value])): > - raise QAPISemError( > - info, > - "pragma %s must be a list of strings" % name) > + def _pragma(name, value, info): > + > + def _check(name, value) -> List[str]: > + if (not isinstance(value, list) or > + any([not isinstance(elt, str) for elt in value])): > + raise QAPISemError( > + info, > + "pragma %s must be a list of strings" % name) > + return value > > - def _pragma(self, name, value, info): > if name == 'doc-required': > if not isinstance(value, bool): > raise QAPISemError(info, > "pragma 'doc-required' must be boolean") > info.pragma.doc_required = value > elif name == 'command-name-exceptions': > - self._check_pragma_list_of_str(name, value, info) > - info.pragma.command_name_exceptions = value > + info.pragma.command_name_exceptions = _check(name, value) > elif name == 'command-returns-exceptions': > - self._check_pragma_list_of_str(name, value, info) > - info.pragma.command_returns_exceptions = value > + info.pragma.command_returns_exceptions = _check(name, value) > elif name == 'member-name-exceptions': > - self._check_pragma_list_of_str(name, value, info) > - info.pragma.member_name_exceptions = value > + info.pragma.member_name_exceptions = _check(name, value) > else: > raise QAPISemError(info, "unknown pragma '%s'" % name) While I appreciate the terseness, I'm not sure I like the generic name _check() for checking one of two special cases, namely "list of string". The other case being "boolean". We could acquire more cases later.