From 5260392290171672006 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 109fba,109af18a94b8a35c X-Google-Attributes: gid109fba,public X-Google-Thread: f78e5,e5cae9ffbf1dd57e X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 1992-10-04 18:05:24 PST Xref: sparky comp.lang.c++:14514 comp.std.c++:1301 Path: sparky!uunet!haven.umd.edu!darwin.sura.net!sgiblab!cs.uoregon.edu!ogicse!das-news.harvard.edu!cantaloupe.srv.cs.cmu.edu!crabapple.srv.cs.cmu.edu!andrew.cmu.edu!sm86+ From: osoelgaultier+@CMU.EDU (Stefan Monnier) Newsgroups: comp.lang.c++,comp.std.c++ Subject: Re: The concept of templates considered ill designed Message-ID: <0enxJ1W00awTMNepU8@andrew.cmu.edu> Date: 4 Oct 92 21:40:17 GMT Article-I.D.: andrew.0enxJ1W00awTMNepU8 References: <1992Oct1.140643.9775@cadsun.corp.mot.com> <1992Oct2.153826.12051@ucc.su.OZ.AU> <23796@alice.att.com> <23801@alice.att.com> Organization: Junior, Math/Computer Science, Carnegie Mellon, Pittsburgh, PA Lines: 37 In-Reply-To: <23801@alice.att.com> Excerpts from netnews.comp.lang.c++: 5-Oct-92 Re: The concept of template.. Andrew Koenig@alice.att. (287) > In article osoelgaultier+@CMU.EDU > (Stefan Monnier) writes: > > But the suggested 'templates with type constraint' would > > permit to change it into an implementation issue. > Really? Why do you think so? > -- > --Andrew Koenig > ark@europa.att.com As are currently implemented templates, you don't know anything about the actual type at compile-time. So that no method calls or variable accesses can be compiled for any variable of 'template type'. The only thing you can do at compile-time with those variables is to store them and retrieve them in a structure, but, again, without making them execute anything. A hashtable (which requires the type to have at least a 'hash' method) couldn't be compiled, as the compiler can know where the 'hash' method will be in the actual type ! That's why Eiffel has those type constraints: it's not a feature, it's just necessary to be able to compile it separately ! (and to typecheck separately also) Stefan ----------------------------------------------------- -- On the average, people seem to be acting normal -- -----------------------------------------------------