From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gdb-return-37829-listarch-gdb=sources.redhat.com@sourceware.org>
Received: (qmail 12199 invoked by alias); 13 Aug 2010 06:41:19 -0000
Received: (qmail 12190 invoked by uid 22791); 13 Aug 2010 06:41:18 -0000
X-SWARE-Spam-Status: No, hits=-0.7 required=5.0	tests=AWL,BAYES_50
X-Spam-Check-By: sourceware.org
Received: from ahmler2.mail.eds.com (HELO ahmler2.mail.eds.com) (192.85.154.72)    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 13 Aug 2010 06:41:13 +0000
Received: from ahmlir5.mail.eds.com (ahmlir5-2.mail.eds.com [192.85.154.135])	by ahmler2.mail.eds.com (8.14.4/8.13.8) with ESMTP id o7D6fAAF005729	for <gdb@sourceware.org>; Fri, 13 Aug 2010 02:41:10 -0400
Received: from ahmlir5.mail.eds.com (localhost [127.0.0.1])	by ahmlir5.mail.eds.com (8.14.4/8.12.10) with ESMTP id o7D6f7RM013718	for <gdb@sourceware.org>; Fri, 13 Aug 2010 02:41:07 -0400
Received: from usplmvpfe001.ent.rt.verigy.net ([192.100.40.4])	by ahmlir5.mail.eds.com (8.14.4/8.12.10) with ESMTP id o7D6f7bB013710	for <gdb@sourceware.org>; Fri, 13 Aug 2010 02:41:07 -0400
X-EDSINT-Source-Ip: 192.100.40.4
Received: from usplmvpbe001.ent.rt.verigy.net ([10.16.58.34]) by usplmvpfe001.ent.rt.verigy.net with Microsoft SMTPSVC(6.0.3790.4675);	 Fri, 13 Aug 2010 01:41:07 -0500
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain;	charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
Subject: [Pretty printers] Can the name or type of a child value change?
Date: Fri, 13 Aug 2010 06:41:00 -0000
Message-ID: <58596C4646708B4BB990C4483997333002F403D9@usplmvpbe001.ent.rt.verigy.net>
From: "Elmenthaler, Jens" <jens.elmenthaler@verigy.com>
To: <gdb@sourceware.org>
X-IsSubscribed: yes
Mailing-List: contact gdb-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <gdb.sourceware.org>
List-Subscribe: <mailto:gdb-subscribe@sourceware.org>
List-Archive: <http://sourceware.org/ml/gdb/>
List-Post: <mailto:gdb@sourceware.org>
List-Help: <mailto:gdb-help@sourceware.org>, <http://sourceware.org/ml/#faqs>
Sender: gdb-owner@sourceware.org
X-SW-Source: 2010-08/txt/msg00077.txt.bz2

Consider the following code example:

  struct JAny {
    union {
      char *text;
      int number;
    } val;

    // 1 -> text, 2 -> number
    int type;
  };

And the following pretty printer:
class AnyPrinter:
    class _iterator:
        def __init__ (self, name, value):
            self.count =3D 0
            self.name =3D name
            self.value =3D value

        def __iter__(self):
            return self

        def next(self):
            if self.count !=3D 0:
                raise StopIteration
=20=20=20=20=20=20=20=20=20=20=20=20
            self.count =3D self.count + 1
            return (self.name, self.value)=20=20=20=20

    def __init__(self, val):
        self.type =3D val['type']
=20=20=20=20=20=20=20=20
        if self.type =3D=3D 1:
            self.value =3D val['val']['text']
            self.name =3D "text"
=20=20=20=20=20=20=20=20=20=20=20=20
        if self.type =3D=3D 2:
            self.value =3D val['val']['number']
            self.name =3D "number"
=20=20=20=20=20=20=20=20=20=20=20=20
    def children(self):
        return self._iterator(self.name, self.value)

    def to_string(self):
        return "JAny"

When stepping in the debugger over a line that changes JAny.type, the name =
and the type of the child value returned by the pretty printer change.

Are the MI variable objects meant to handle this?

Greetings, Jens.