From: Georg Bauhaus <sb463ba@d2-hrz.uni-duisburg.de>
Subject: Re: Generic child units
Date: Sat, 17 May 2003 00:23:41 +0000 (UTC)
Date: 2003-05-17T00:23:41+00:00 [thread overview]
Message-ID: <ba3ved$qbt$1@a1-hrz.uni-duisburg.de> (raw)
In-Reply-To: ubry6heul.fsf@nasa.gov
Stephen Leake <Stephe.Leake@nasa.gov> wrote:
: Rodrigo Garc?a <rodrigo.garcia.ARROBA.epfl.ch> writes:
:
:> I need some enlightment in this area... Let us suppose that I have two
:> generic packages declared in separate files and one is the parent of
:> the other:
:>
:> generic
:> type Elem is private;
:> package Parent is
:> type Vector is array (Integer range <>) of Elem;
:> end Parent;
:>
:> generic
:> package Parent.Child is
:> subtype Vector2D is Vector (1 .. 2);
:> end Parent.Child;
:>
:> How can I instantiate the child package
:
: with Parent.Child;
: procedure Foo is
: package Par is new Parent (Elem => Integer);
: package Chi is new Par.Child;
: begin
: ...
: end Foo;
:
: Note that the second instantiation is "Par.Child", not "Parent.Child".
I find it useful to compare to this variation of the packages, at least
it has shed some light (I think :-/) as far as the instantiation sequence
is concerned:
generic
type Elem is private;
package Parent is
type Vector is array (Integer range <>) of Elem;
generic
package Child is
subtype Vector2D is Vector (1 .. 2);
end Child;
end Parent;
So, elsewhere, you can't have an instance of child without an instance
of parent.
But you can have an instance of Child in Parent's body. I don't
know why, exactely, though.
(No wonder that the editors next door tell me that programmers
are funny people :-)
-- Georg
next prev parent reply other threads:[~2003-05-17 0:23 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-13 17:46 Generic child units
2003-05-13 18:38 ` Stephen Leake
2003-05-13 19:18 ` David C. Hoos
2003-05-14 7:56 `
2003-05-15 16:30 ` Stephen Leake
2003-05-16 1:08 ` Robert A Duff
2003-05-16 19:24 ` Stephen Leake
2003-05-16 23:47 ` Georg Bauhaus
2003-05-17 0:57 ` Robert A Duff
2003-05-17 1:11 ` Georg Bauhaus
2003-05-17 1:04 ` Robert A Duff
2003-05-16 23:44 ` Georg Bauhaus
2003-05-17 0:23 ` Georg Bauhaus [this message]
2003-05-17 1:00 ` Robert A Duff
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