Re: Unconstrained Array ??

["David C. Hoos, Sr." <david.c.hoos.sr@ada95.com>]

Duncan Woodward <drdw@synthsoft.demon.co.uk> wrote in message
news:934306216.27590.0.nnrp-10.c2de38ef@news.demon.co.uk...
> hi;
> I want to create a package that handles actions upon
> a multi dimensional unconstrained array.
>
> It is likely that I've approached this problem from the
> wrong direction, but this is where I'm at..
>
> package array_Handler is
>
> type Container_Matrix is array(POSITIVE range <>,
>                                             POSITIVE range <>,
>                                             POSITIVE range <>) of Boolean;
>
> procedure1 Set_Container_Size(x,y,z:Integer);
>
>                 -- this procedure takes in the three axis values for
>                 -- the array index ranges.
>                 -- Creates instance of Container_Matrix using parameters
>                 -- x,y,z.
>
> procedure2 ...etc
> procedure3 ...etc
>
> end array_Handler;
>
> PROBLEM: How do I create an instance of type Container_Matrix
> that is visible to all procedures in the package.
>
> A single global declaration would be fine if the array sizes were know
> in advance!
>

If you're going to have multiple subprograms accessing the same object,
it sounds like a candidate for a protected type.

Why not something like the following example?

package array_Handler is

   type Matrix is array
     (Positive range <>, Positive range <>, Positive range <>)
     of Boolean;

   protected type Container_Matrix
     (X: Positive;
      Y: Positive;
      Z : Positive) is

      procedure Action_2;

      procedure Action_3;

   private

      The_Matrix : Matrix (1 .. X, 1 .. Y, 1 .. Z);

   end Container_Matrix;

end array_Handler;

with Ada.Text_IO;
package body array_Handler is

   ----------------------
   -- Container_Matrix --
   ----------------------

   protected body Container_Matrix is

      --------------
      -- Action_2 --
      --------------

      procedure Action_2 is
      begin
         Ada.Text_IO.Put_Line
           ("Action_2: " &
            "X range is" &
            Positive'Image (The_Matrix'First (1)) & " .." &
            Positive'Image (The_Matrix'Last (1)) & "; " &
            "Y range is" &
            Positive'Image (The_Matrix'First (2)) & " .." &
            Positive'Image (The_Matrix'Last (2)) & "; " &
            "Z range is" &
            Positive'Image (The_Matrix'First (3)) & " .." &
            Positive'Image (The_Matrix'Last (3)) & ".");
      end Action_2;


      --------------
      -- Action_3 --
      --------------

      procedure Action_3 is
      begin
         Ada.Text_IO.Put_Line
           ("Action_3: " &
            "X range is" &
            Positive'Image (The_Matrix'First (1)) & " .." &
            Positive'Image (The_Matrix'Last (1)) & "; " &
            "Y range is" &
            Positive'Image (The_Matrix'First (2)) & " .." &
            Positive'Image (The_Matrix'Last (2)) & "; " &
            "Z range is" &
            Positive'Image (The_Matrix'First (3)) & " .." &
            Positive'Image (The_Matrix'Last (3)) & ".");
      end Action_3;

   end Container_Matrix;

end array_Handler;

with Array_Handler;
procedure Test_Array_Handler is

   The_Array : Array_Handler.Container_Matrix (3, 4, 5);

begin

   The_Array.Action_2;

   The_Array.Action_3;

end Test_Array_Handler;