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=-0.3 required=5.0 tests=BAYES_00, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: 103376,839916f6ca3b6404 X-Google-Attributes: gid103376,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news1.google.com!news2.google.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local01.nntp.dca.giganews.com!nntp.bt.com!news.bt.com.POSTED!not-for-mail NNTP-Posting-Date: Wed, 04 Mar 2009 19:31:34 -0600 From: Brian Drummond Newsgroups: comp.lang.ada Subject: Re: not null Date: Thu, 05 Mar 2009 01:32:19 +0000 Reply-To: brian@shapes.demon.co.uk Message-ID: References: <49ae93bc$0$31872$9b4e6d93@newsspool3.arcor-online.net> <761a4fb8-de91-43b3-b420-55dbc06a61e7@k9g2000prh.googlegroups.com> X-Newsreader: Forte Agent 1.7/32.534 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Usenet-Provider: http://www.giganews.com X-AuthenticatedUsername: NoAuthUser X-Trace: sv3-T9TRJ5aoSh6hBnFf1wCPVmNN5XB6XiXvfDxeThgZdZkD5gq77laa2vNMJIWODw1Nk4j4DA3WdLp0ttC!y7KuzquQa/ZhJ3Tx4H90a4j/2SvKJOBm6DlF1X6lmi1WZEmzQ+16LgBAJ8LzrULIC6sr/4xkRrb7!vxSH X-Complaints-To: abuse@btinternet.com X-DMCA-Complaints-To: abuse@btinternet.com X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.39 Xref: g2news1.google.com comp.lang.ada:3955 Date: 2009-03-05T01:32:19+00:00 List-Id: On Wed, 4 Mar 2009 08:09:56 -0800 (PST), Adam Beneschan wrote: >On Mar 4, 6:56 am, Hyman Rosen wrote: >> Georg Bauhaus wrote: >> > As said to have been seen on /. >> > another financial disaster, again caused >> > by making references to nothing, in Algol W, >> >http://qconlondon.com/london-2009/presentation/Null+References:+The+B... >> >> You are misreading the abstract. First of all, it's not >> about some particular incident. He's talking about the >> overall impact. Second, he's not talking about failure >> to check for null references, he's talking about having >> null references at all, so Ada is no better. > >I'm having difficulty understanding the point. You have to have the >idea of the lack of a reference. How else would you implement a >linked list abstraction? Possibly by pointing from the end back to the list head. It would make the "end of list" test more expensive (the head might have to be kept in a register or passed around as another argument). I don't think it would be pretty, but can't see any fundamental reason why it shouldn't work. - Brian