Re: How to write TYPECASE in Ada 95?

[Matthew Heaney <matthew_heaney@acm.org>]

Matthew Heaney <matthew_heaney@acm.org> writes:

> Note that there's another way to illustrate these concepts, that does
> not require heap.  Just use a declare block to declare each new kind of
> point, as follows:

Here is yet another way to do this, by declaring the objects to be type
Point'Class.  This is probably closer to David's original example.

Like my earlier post, the example here doesn't require the use of heap.


with Ada.Text_Io;
with Ada.Unchecked_Deallocation;
with Points; use Points;
procedure Test_Points is
begin

   declare
      P : Point'Class := Tall_Point'(3.0, 4.0, 5.0);
   begin
      Points.Show_Type (P);
      Points.Show_Properties (P);
   end;

   declare
      P : Point'Class := Painted_Point'(3.0, 4.0, Points.Blue);
   begin
      Points.Show_Type (P);
      Points.Show_Properties (P);
   end;

end Test_Points;