From: Stephen Leake <stephen_leake@acm.org>
Subject: Re: prohibit certain generic instantiations in Ada 2005
Date: Sat, 11 Feb 2006 10:36:58 -0500
Date: 2006-02-11T10:36:58-05:00 [thread overview]
Message-ID: <uzmkxrjol.fsf@acm.org> (raw)
In-Reply-To: 1139645084.563448.239040@g47g2000cwa.googlegroups.com
matteo.bordin@gmail.com writes:
> I will provide a proper example in C++. With this code I can prohibit
> instantiation of template My_Class with T=int.
>
> class Checker{
> public:
> static void check(float){};
> private:
> static void check(int){};
> };
>
> template <class T>
> class My_Class{
> public:
> My_Class(){
> T t;
> Checker::check(t);
>
> }
> };
>
> int main(){
>
> My_Class<int> mc = My_Class<int>(); //COMPILE TIME ERROR!!!!
> //The error comes from the fact that Checker::check(int) is private
> My_Class<float> mc2 = My_Class<float>(); //OK!!!
> };
>
> When I said that the compilation model for template of Ada is similar
> to C++, I meant in regards to compile-time code generation (opposed to
> the model of Java generics). In both languages (Ada and C++), templates
> can be used as a generative environment.
Ok, you _can_ do this in C++. But they question remains; _why_ do you
want to do this? What is it that Checker does that is appropriate for
all types, except 'int'?
>
> just want to know f here is a way to reproduce the C++ code I
> provided in Ada (2005).
You can write code in the execution part of a package body (after the
'begin') that does some checking, and raises an exception. Most
compilers will warn at compile time that a run-time construct will
raise an exception.
--
-- Stephe
next prev parent reply other threads:[~2006-02-11 15:36 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-09 18:01 prohibit certain generic instantiations in Ada 2005 matteo.bordin
2006-02-09 20:02 ` Matthew Heaney
2006-02-10 14:18 ` matteo.bordin
2006-02-10 18:25 ` Dmitry A. Kazakov
2006-02-10 19:03 ` Georg Bauhaus
2006-02-11 10:45 ` Dmitry A. Kazakov
2006-02-11 8:04 ` matteo.bordin
2006-02-11 9:54 ` Martin Krischik
2006-02-11 10:20 ` matteo.bordin
2006-02-11 12:46 ` Martin Krischik
2006-02-11 10:45 ` Dmitry A. Kazakov
2006-02-11 22:20 ` Jeffrey R. Carter
2006-02-11 15:36 ` Stephen Leake [this message]
2006-02-12 8:55 ` matteo.bordin
2006-02-12 9:49 ` Dmitry A. Kazakov
2006-02-12 12:41 ` matteo.bordin
2006-02-13 19:14 ` Matthew Heaney
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