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=-1.9 required=5.0 tests=BAYES_00 autolearn=unavailable autolearn_force=no version=3.4.4 Path: eternal-september.org!reader01.eternal-september.org!feeder.eternal-september.org!nntp-feed.chiark.greenend.org.uk!ewrotcd!newsfeed.xs3.de!news.jacob-sparre.dk!franka.jacob-sparre.dk!pnx.dk!.POSTED.rrsoftware.com!not-for-mail From: "Randy Brukardt" Newsgroups: comp.lang.ada Subject: Re: Intervention needed? Date: Tue, 12 Mar 2019 16:53:01 -0500 Organization: JSA Research & Innovation Message-ID: References: Injection-Date: Tue, 12 Mar 2019 21:53:02 -0000 (UTC) Injection-Info: franka.jacob-sparre.dk; posting-host="rrsoftware.com:24.196.82.226"; logging-data="11607"; mail-complaints-to="news@jacob-sparre.dk" X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2900.5931 X-RFC2646: Format=Flowed; Original X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.7246 Xref: reader01.eternal-september.org comp.lang.ada:55855 Date: 2019-03-12T16:53:01-05:00 List-Id: "Lucretia" wrote in message news:bba8f6a8-36ce-4bed-bd84-8a9ea7dc02f7@googlegroups.com... > On Tuesday, 12 March 2019 18:14:04 UTC, Olivier Henley wrote: >> On Tuesday, March 12, 2019 at 12:32:34 PM UTC-4, Jeffrey R. Carter wrote: ... >> It has nothing to do with ourselves... me my, my. >> >> I suppose we did so to set the record straight about Ada to a community >> that has 'A LOT' of traction and think they are reinventing the wheel... >> by staying blind to Ada. > > It's also to do with the fact that Rust isn't all that either. It > literally only adds the > pointer ownership thing, nothing else, yet this is the hype this train is > carrying and > lods of people are getting on it, instead of getting on Ada. My understanding is that the SPARK people are far into designing ownership contracts for Spark. It's also possible that Ada 2020 will have a form of pointer ownership. (Unfortunately, we didn't make any conclusions on that during yesterday's meeting, so it's still in limbo, and we're getting very close to the finish line.) The current problem is that in Ada 2020 as it stands, it's not possible to write a containers implementation in pure Ada. You'd have to have some implementation hack to turn off some of the Legality Rules. Tucker has designed a solution, based on an ownership mechanism, but as it is new and barely vetted, it's unclear what we will do with it ultimately. Note that this solution will not provide the perfect safety that you would get with SPARK or Rust, but it would form the foundation of the SPARK solution and it would clearly catch a lot of issues with using pointers to implement ADTs. (And there is little other reason to use pointers, IMHO.) Randy.