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-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,fdc75443ea18fb32 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-11-30 13:31:11 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!wn4feed!wn3feed!worldnet.att.net!4.24.21.153!chcgil2-snh1.gtei.net!chcgil2-snf1.gtei.net!news.gtei.net!news.huji.ac.il!not-for-mail From: "Ehud Lamm" Newsgroups: comp.lang.ada Subject: Re: Queue Date: Fri, 30 Nov 2001 23:07:11 +0200 Organization: The Hebrew University of Jerusalem Message-ID: <9u8smr$vd3$1@news.huji.ac.il> References: <%QRM7.39743$xS6.65958@www.newsranger.com><9u0qhb$pq5$1@nh.pace.co.uk> <3C049B27.D7D19EBF@mida.se> NNTP-Posting-Host: di3-80.dialin.huji.ac.il X-Trace: news.huji.ac.il 1007154716 32163 132.64.13.80 (30 Nov 2001 21:11:56 GMT) X-Complaints-To: abuse@news.huji.ac.il NNTP-Posting-Date: Fri, 30 Nov 2001 21:11:56 +0000 (UTC) X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.00.2014.211 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2014.211 Xref: archiver1.google.com comp.lang.ada:17244 Date: 2001-11-30T23:07:11+02:00 List-Id: Brian Rogoff wrote in message news:Pine.BSF.4.40.0111300447310.89131-100000@bpr.best.vwh.net... > > The excessive instantiations that you need in an Ada version of the STL > become ponderous IMO. I believe this is a fundamental problem with Ada > generics, and perhaps even a fundamental issue in statically typed > languages, namely, when do we prefer explicit (manifest?) types and when > do we prefer implicit types. My own opinion is that I'd like a language > with both. Ada has only the first, and while modern high level languages > (think ML and Haskell here) provide both I'm a bit unsatisfied with the > way it all fits together (not to drift too far, but I'd like something > like Haskell's type classes and not just ML's universal style of > polymorphism, *and* I want a decent module system). I guess I'm not meant > to be happy with any programming language :-). > I am with you on this. In a sense this is a language engineering issue. We want to safety brought by explicit instanations etc., but we don't want to have to use it all the time. I am still not sure what's the best way of combining these features, but it seems to me there shouldn't be a theoretical problem here, just a need for smart language design. > Just so I don't sound entirely negative, generic formal package > parameters, and the signature trick, really make something like the STL, > or Bishop's approach, a lot cleaner in Ada 95 than was possible in Ada 83. > It also makes the STL easier to understand, since you can express the > notion of "iterator category" (I think that's what Alex Stepanov called > it, I can't remember since it was a few years ago) pretty directly with > a few signatures (Forward_Iterator_Sig, Bidirectional_Iterator_Sig, etc.). > Signature packages are a very important concept, and add expressive power that I like. Indeed, formal packages were a great addition to the language. But they can be improved upon (for example, I'd like to be able to elegantly require that two formal packages share some parameters, etc.) Ehud