From: Stephen Leake <Stephe.Leake@nasa.gov>
Subject: Re: Need advice re package organization.
Date: 01 Aug 2003 17:33:30 -0400
Date: 2003-08-01T21:34:53+00:00 [thread overview]
Message-ID: <uu191kqqd.fsf@nasa.gov> (raw)
In-Reply-To: vilhrvdbtidm49@corp.supernews.com
"Randy Brukardt" <randy@rrsoftware.com> writes:
> "Warren W. Gay VE3WWG" <ve3wwg@cogeco.ca> wrote in message
> news:7GfWa.5186$mv6.907516@news20.bellglobal.com...
> <snip>
> >
> > We're talking about protected access of classes (C++).
>
> As I said above, I don't know C++ well enough to know exactly what it is
> that you are proposing. And in any case, Ada is not C++. Please describe
> what you want in Ada terms, with Ada syntax.
Perhaps I can help, since I beleive I do know C++ and Ada well enough
:).
The C++ notions of public, protected, and private member functions do
not map one-to-one into Ada, but they map fairly well according to the
following scheme (data members below):
C++ Ada
public public part of package spec
protected private part of package spec
private package body
C++ can make the same distinctions among data members of a record
type. For example:
class Foo
{
public:
int A;
protected:
int B;
private:
int C;
}
A is visible to all children and clients of Foo; B is visible to
children of Foo; C is only visible within Foo.
To achieve the same visibility in Ada, we need to break up the record
type:
package Foo_Package is
type Protected_Foo is private;
type Foo is record
A : Integer;
Protected_Stuff : Protected_Foo;
end record;
private
type Private_Foo;
type Private_Foo_Access is access Private_Foo;
type Protected_Foo is record
B : integer;
Private_Stuff : Private_Foo_Access;
end record;
end Foo_Package;
package body Foo_Package is
type Private_Foo is record
C : Integer;
end type;
end Foo_Package;
If you are comming from a C++ background, the Ada approach seems
contorted. From an Ada point of view, the C++ approach seems
simplistic :).
I believe I have seen proposals that allow a single Ada record to have
public and private parts, something like:
package Foo_Package is
type Foo is record
A : Integer;
end record with private;
private
type Foo is record with private
B : integer;
end record;
end Foo_Package;
But that only achieves the C++ protected visibility, not the private.
--
-- Stephe
next prev parent reply other threads:[~2003-08-01 21:33 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-26 13:08 Need advice re package organization Bobby D. Bryant
2003-07-26 14:25 ` Robert I. Eachus
2003-07-26 15:27 ` Warren W. Gay VE3WWG
2003-07-26 22:00 ` Robert I. Eachus
2003-07-27 22:01 ` chris
2003-07-28 2:53 ` Robert I. Eachus
2003-07-29 4:52 ` Richard Riehle
2003-07-27 22:02 ` Warren W. Gay VE3WWG
2003-07-28 8:38 ` Dmitry A. Kazakov
2003-07-29 17:18 ` Warren W. Gay VE3WWG
2003-07-30 8:42 ` Dmitry A. Kazakov
2003-07-30 21:00 ` Warren W. Gay VE3WWG
2003-07-30 22:46 ` Randy Brukardt
2003-07-31 16:39 ` Warren W. Gay VE3WWG
2003-07-31 17:31 ` Randy Brukardt
2003-07-31 21:00 ` Warren W. Gay VE3WWG
2003-07-31 22:13 ` Robert I. Eachus
2003-08-01 12:51 ` Warren W. Gay VE3WWG
2003-07-31 5:57 ` Matthew Heaney
2003-07-31 16:57 ` Warren W. Gay VE3WWG
2003-07-31 22:33 ` Robert I. Eachus
2003-08-01 2:58 ` Chad R. Meiners
2003-08-01 13:51 ` Stephen Leake
2003-08-01 22:15 ` Robert I. Eachus
2003-08-04 13:45 ` Stephen Leake
2003-08-01 13:01 ` Warren W. Gay VE3WWG
2003-07-31 9:04 ` Dmitry A. Kazakov
2003-07-31 16:59 ` Warren W. Gay VE3WWG
2003-07-31 20:41 ` Randy Brukardt
2003-07-31 21:15 ` Warren W. Gay VE3WWG
2003-08-01 20:04 ` Randy Brukardt
2003-08-01 21:33 ` Stephen Leake [this message]
2003-08-04 19:40 ` Randy Brukardt
2003-08-04 19:52 ` Stephen Leake
2003-08-05 3:36 ` Richard Riehle
2003-08-05 4:03 ` Hyman Rosen
2003-08-05 7:16 ` Dmitry A. Kazakov
2003-07-26 17:03 ` Nick Roberts
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