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=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,64f0fb07a88662b1 X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news4.google.com!news.glorb.com!in.100proofnews.com!in.100proofnews.com!border2.nntp.dca.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local01.nntp.dca.giganews.com!nntp.megapath.net!news.megapath.net.POSTED!not-for-mail NNTP-Posting-Date: Thu, 31 Mar 2005 20:28:04 -0600 From: "Randy Brukardt" Newsgroups: comp.lang.ada References: <31T2e.5362$AI.4802@reader1.news.jippii.net> Subject: Re: Contract checking in Ada Date: Thu, 31 Mar 2005 20:30:25 -0600 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4927.1200 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4927.1200 Message-ID: NNTP-Posting-Host: 64.32.209.38 X-Trace: sv3-5ZR7FsfcvPhWzb0Rd+C6Ij8WRSiFAQi0faqOazj8rYOi8395qJLu49Tu1DhWW18JAWMNix/GEuh2Lqv!iCJd3EGPZ+eQJcHS1PfP0yBXT7g890TVdbTR+4zsr9SAFX5uJmGeWEVO8Coto5uSnUOrhiGyQf/q X-Complaints-To: abuse@megapath.net X-DMCA-Complaints-To: abuse@megapath.net X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.32 Xref: g2news1.google.com comp.lang.ada:10199 Date: 2005-03-31T20:30:25-06:00 List-Id: "Martin Dowie" wrote in message news:d2hcqs$ct0$1@sparta.btinternet.com... > Tapio Kelloniemi wrote: > > But back to my original question, how could I implement programming by > > contract now when the designers have abandoned it in their great wisdom? > > And I don't think you're being very fair to the Ada0Y team. The effort > that has gone into/is going into it is still huge! > > It would be great if there were dozens of volunteers to promote new > proposals but the sad truth is very few people are capable of writing an > amendment to the RM (and I certainly include myself is the 'not able' > camp). When people talk about "language lawyers" it isn't far from the > truth! The knowledge of the language has to be absolutely inside-out if > you want to be able to amend the actual language - not so much the > standard library but even that's tricky. Yes, and they have to be very carefully reviewed, both for language issues and for implementation ones. (You don't want the new features to cause programs to run much slower -- the dreaded "distributed overhead"). These proposals kept getting messier and messier, and that played a part in their eventually being abandoned. For instance, Postconditions required a mechanism to get at the original values of parameters. Which meant that those values had to be saved somewhere. That would be a huge performance hit unless it is possible to tell in advance whether or not the original value would be required. We never had a proposal with that property (it really needs to be visible on a purely syntax basis; otherwise it can be too complex to figure out, as it would depend on name resolution and visibility). We certainly had to prioritize our work, and input like the Ada UK vote that Martin mentioned was very helpful in doing that. You don't please your customers by doing the things that they are least interested in! (Note that input like this was the reason that the containers library got added; it just seemed too big to undertake, but the consistent message from the user community was "this is important". So we buckled down and did it - but of course other things, like the exception hierarchies and the pre/post condition stuff got dropped to make room.) Randy.