From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-0.9 required=5.0 tests=BAYES_00,FORGED_GMAIL_RCVD, FREEMAIL_FROM autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: 103376,6b1a1ed8b075945 X-Google-Attributes: gid103376,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news2.google.com!postnews.google.com!22g2000hsm.googlegroups.com!not-for-mail From: Maciej Sobczak Newsgroups: comp.lang.ada Subject: Re: Allocators and exceptions Date: Tue, 11 Sep 2007 02:19:37 -0700 Organization: http://groups.google.com Message-ID: <1189502377.626510.172690@22g2000hsm.googlegroups.com> References: <1189323618.588340.87180@o80g2000hse.googlegroups.com> <1189369871.672082.162750@50g2000hsm.googlegroups.com> <1189460936.295604.143720@r29g2000hsg.googlegroups.com> NNTP-Posting-Host: 137.138.37.241 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" X-Trace: posting.google.com 1189502377 8042 127.0.0.1 (11 Sep 2007 09:19:37 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Tue, 11 Sep 2007 09:19:37 +0000 (UTC) In-Reply-To: User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.12) Gecko/20070724 Red Hat/1.5.0.12-0.3.slc3 Firefox/1.5.0.12,gzip(gfe),gzip(gfe) Complaints-To: groups-abuse@google.com Injection-Info: 22g2000hsm.googlegroups.com; posting-host=137.138.37.241; posting-account=ps2QrAMAAAA6_jCuRt2JEIpn5Otqf_w0 Xref: g2news2.google.com comp.lang.ada:1883 Date: 2007-09-11T02:19:37-07:00 List-Id: On 11 Wrz, 11:16, "Dmitry A. Kazakov" wrote: > >>> P.S. Exceptions in constructors is a bad idea. > > > No, it's a very good idea. Otherwise you have to deal with half-baked > > objects, which is Even Bigger Mess (tm). > > This is what you get when the exception is propagated out of a constructor. In this case I want the constructor to be rolled back. Without exceptions (and rollback) the only option for handling errors in initialization of (sub)components is to leave them half-baked. When I create a new object and there is some error on the way, I want to consider the object as if it never existed. This is what allows me to keep abstractions and invariants: either I have the complete object with its guaranteed invariants, or there is nothing. Anything in between is mess. -- Maciej Sobczak http://www.msobczak.com/