Default value for a record component

[Maciej Sobczak <see.my.homepage@gmail.com>]

Consider:

package P is
   type T is record
      V : Integer := 5;
   end record;
end P;

Above, T.V will have 5 as a default value whenever the instance of T
is created without any explicit initialization.

I would like extend it and do this:

package P is
   type T is record
      V : Integer := Get_Default_Value;
   end record;
private
   function Get_Default_Value return Integer;
end P;

without losing any of the properties of the original solution and
without "leaking" any implementation detail to the public view. The
idea is, of course, to compute the default value at run-time, each
time the new object is created - but without touching the general
"look&feel" of the original code (so that for example Controlled is
excluded).
Is it possible?

--
Maciej Sobczak
http://www.msobczak.com/