Re: I'm facing an issue with: call to abstract procedure must be dispatching

[Shark8 <onewingedshark@gmail.com>]

On Sunday, December 13, 2015 at 7:20:40 PM UTC-7, Jeffrey R. Carter wrote:
> 
> I wouldn't put the state in the private part.
> Instead, I'd put it in the body

I tend to go with body, though there are some instances where you need to put it in private. (Namely: when child units need to access the internal representation of the data.)

> I'd also use "+ 1" or "- 1", since those are clearer.

The reason I used Succ and Pred was that I was originally going to [also] include a generic version, which would need to replace Natural w/ the formal type parameter:

Generic
  Type Data_Type is (<>);
  Default : in Data_Type;
Package Generic_Counter is
  Procedure Inc;
  Procedure Dec;
  Function Value Return Data_Type;
End Generic_Counter;

Package Body Generic_Counter is
  Data : Data_Type := Default;
  Procedure Inc is
  begin
   Data:= Data_Type'Succ( Data );
  end Inc;

  Procedure Dec is
  begin
   Data:= Data_Type'Pred( Data );
  end Dec;

  Function Value return Data_Type is
  ( Data );
End Generic_Counter;