Re: Why both "with" and "use"?

[Matthew Heaney <matthew_heaney@acm.org>]

bill <bill@newsguy.com> writes:

> Also, in Java a package seems to have different purpose than with Ada. In
> Java a package is a collection of classes. In OO Ada, a package usually
> contains one tagged type. or is this not the normal practice?

A package exports a collection of entities that are "highly cohesive."
As such, it often makes sense to bundle types together in the same
package.  For example:

generic
  type Item_Type is private;
package Stacks is

   type Stack_Type is limited private;

   procedure Push 
     (Item : in     Item_Type;
      On   : in out Stack_Type);

   <etc>

   
   type Stack_Iterator is private;

   function Initialize 
     (Stack : Stack_Type) return Stack_Iterator;

   function Get_Item
     (Iterator : Stack_Iterator) return Item_Type;

   procedure Advance 
     (Iterator : in out Stack_Iterator);

  <etc>

end Stacks;


Here, we have an example of a stack type and its iterator type, together
in one package.  This is entirely natural and appropriate.