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From: Oliver Kellogg <okellogg@users.sourceforge.net>
Newsgroups: comp.lang.ada
Subject: global package scope designator?
Date: Mon, 5 Apr 2010 09:39:33 +0200
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Date: 2010-04-05T09:39:33+02:00
List-Id: <comp.lang.ada>

In C++, a leading "::" before a reference to a namespace denotes the 
global namespace.
There does not seem to be an equivalent for this in Ada.
I now ran into a situation where I felt this to be a lack.

Here is an example (the original problem involved packages nested three 
levels deep which I reduced here to two levels for simplicity):

-- File: gui.ads
package gui is
   type Obj is new Integer;
end gui;

-- File: mcc.ads
package mcc is
end mcc;

-- File: mcc-gui.ads
package mcc.gui is
   function F return Natural;
end mcc.gui;

-- File: mcc-gui.adb
with gui;
package body mcc.gui is
   function F return Natural is
   begin
      return gui.Obj'Size;
   end F;
end mcc.gui;

$ gcc -c mcc-gui.adb
$ mcc-gui.adb:6:17: "Obj" not declared in "gui"

The package mcc.gui hides the library level package gui.

In C++, we could write
    ::gui::obj
to denote the desired namespace.

Is this something that would be worth adding in a future revision of Ada?

Thanks,

  Oliver


P.S. For the original problem, see
http://svn.savannah.gnu.org/viewvc?view=rev&root=rapid&revision=87