Re: OO Style with Ada Containers

[Matthew Heaney <mheaney@on2.com>]

On Nov 26, 2:09 pm, braver <delivera...@gmail.com> wrote:
> On Nov 26, 4:45 pm, Matthew Heaney <matthewjhea...@earthlink.net>
> wrote:
>
> So in this case Handle goes away altogether?

It was intended only to demonstrate another way to declare the type
(at least, the public part).  Implementation issues are orthogonal.

You'd only need the Rosen Trick if you have a function that has side-
effect (as function Word in my original example).

Another possibility is:

   F : aliased File_Type;
   S : Scanner (F'Access);
begin

Another possibility is:

  procedure Get_Next (S : in out Scanner; Word : out
Unbounded_String);

Yet another possibility is:

  procedure Get_Next
    (S    : in out Scanner;
     Word : out String;
     Last : out Natural);

Or just:

   function Has_Word (S : Scanner) return Boolean;
   function Word (S : Scanner) return String;
   procedure Get_Next (S : in out Scanner);

or:

  function Get_Next (S : Scanner) return Boolean;
  function Word (S : Scanner) return String;

or how about this (perhaps simplest of all, since it hides explicit
loops):

generic
  with procedure Process (Word : String);
procedure Generic_Scan (File : File_Type);