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,c0d427d5f4af20f8 X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!postnews.google.com!f14g2000cwb.googlegroups.com!not-for-mail From: "REH" Newsgroups: comp.lang.ada Subject: Re: generics in Ada 83 Date: 13 Sep 2005 11:43:05 -0700 Organization: http://groups.google.com Message-ID: <1126636985.067939.27760@f14g2000cwb.googlegroups.com> References: <1126617980.932226.320710@g43g2000cwa.googlegroups.com> <4326d73a$1_1@glkas0286.greenlnk.net> <1126629046.328151.40970@g47g2000cwa.googlegroups.com> NNTP-Posting-Host: 192.35.35.34 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Trace: posting.google.com 1126636990 22574 127.0.0.1 (13 Sep 2005 18:43:10 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Tue, 13 Sep 2005 18:43:10 +0000 (UTC) In-Reply-To: User-Agent: G2/0.2 X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.10) Gecko/20050716,gzip(gfe),gzip(gfe) Complaints-To: groups-abuse@google.com Injection-Info: f14g2000cwb.googlegroups.com; posting-host=192.35.35.34; posting-account=lnUIyw0AAACoRB2fMF2SFTIilm8F10q2 Xref: g2news1.google.com comp.lang.ada:4621 Date: 2005-09-13T11:43:05-07:00 List-Id: Martin Dowie wrote: > REH wrote: > > Martin Dowie wrote: > > > >>REH wrote: > >> > >>>Is there a way to define a default for the with'd procedure in the > >>>following example in Ada 83: > >>> > >>>generic > >>> type X is private; > >>> with procedure Y(Z : in X); > >>>package Foo; > >>> > >>>I want to define a default for Y, but how can I without knowing X? > >>> > >>>I have a generic package that has several with'd procedures, but > >>>depending on what services the package provides are use, only a few of > >>>the procedures may need to be defined. I'd like to just default the > >>>unused ones to stubs. > >> > >>Same as Ada95: > >> > >>generic > >> type X is private; > >> with procedure Y (Z : X) is <>; > >>package Foo is > >>end Foo; > >> > >>Or do you mean you want the compiler to magically insert a 'null' procedure > >>if there isn't a matching procedure Y for whatever type X happens to be? If > >>that's the case you can't do that. There has to be some procedure (even one > >>that's only 'begin null end;') for each type. > >> > >>Cheers > >> > >>-- Martin > > > > > > defining it with a box won't work. There would have to a procedure > > already defined. What I want is something like: > > > > generic > > type X is private; > > with procedure Y(Z : in X) is P; > > package Foo > > > > > > but of course P must already take into account X. With '95 I think I > > could just with a generic package containing the stubs, but I can > > figure out a way in '83. > > Yes, how can you have 'P' know which X? > > The best I can see is: > > package A is > type A_T is private; > procedure Y (Z : A_T); > private > type A_T is new Integer; > end A; > > generic > type X is private; > with procedure Y (Z : X) is <>; > package B is > end B; > > with A; use A; > with B; > > package C is > new B (A_T); -- Picks up 'Y' by default > > Cheers > > -- Martin That seems reasonable. Two questions: 1) If I have Y1 through Yn, Do I define the ones I care about when I instantiate B or do I define then in C, before B? 2) is there a way to avoid having to include A?