Re: types in procedure arguments

[bobduff@world.std.com (Robert A Duff)]

In article <52piii$8n7@noc2.drexel.edu>,
Chris Papademetrious <st92j0gw@dunx1.ocs.drexel.edu> wrote:
> I have gotten some replies via email, and am beginning to believe
>that this is a more interesting problem than I first thought!  Here's
>a very simplified version of the situation.  Essentially, in the real
>problem, I'm using a presupplied doubly-linked-list package and vector
>math package (gotta put that reuse principle to work, right?).

Now that I see the source code, I see what you're talking about.
You need to have just one instantiation of Tst_Double_List, not two.
You could make that a library unit, and import it into both
Tst_Best_Congruence and Tst.  However, I assume Tst_Best_Congruence
is the re-used thing, and you don't want to modify it.  In that case,
you could do something like this:

    with Tst_Best_Congruence;
    with Tst_Vectors;
    procedure Tst is

      package Vec_List renames Tst_Best_Congruence.Vec_List;
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

      L: Vec_List.LIST_ID;
    begin
      Tst_Best_Congruence.Best_Congruence(L);
    end Tst;

Or, don't use the renaming, and just say:

    L: Tst_Best_Conguence.Vec_List.LIST_ID;

Or, use use_clauses:

    with Tst_Best_Congruence;
    use Tst_Best_Congruence;
    use Tst_Best_Congruence.Vec_List;
    with Tst_Vectors;
    procedure Tst is
      L: LIST_ID;
    begin
      Best_Congruence(L);
    end Tst;

(I didn't compile these -- sorry for any silly mistakes.)

>  procedure Best_Congruence
>  (
>     List: in Point_List.LIST_ID
>  ) is
>  begin
>    List := List;

That's illegal -- you can modify an 'in' parameter.

- Bob