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

[Shark8 <onewingedshark@gmail.com>]

On Tuesday, December 8, 2015 at 4:04:08 PM UTC-7, Serge Robyns wrote:
> 
> How do I then pass the context?  I mean, now I pass the parameter around.  through global variables?

No, you use the package.
If you want a single application-wide object you can use a package. Here is a single counter:


Package Counter is
  Procedure Inc;
  Procedure Dec;
  Function Value Return Natural;
Private
  Data : Natural := 0;
End Counter;

Package Body Counter is
  Procedure Inc is
  begin
   Data:= Natural'Succ( Data );
  end Inc;

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

  Function Value return Natural is
  ( Data );
End Counter;

You could also enclose that sort of logic in a task or protected object; and if you need multiple singletons you could always use a generic version and then make an instance for each needed singleton.

What those above are warning you against is trying to write C (or C++) in Ada. There's a lot of differences that can usually greatly simplify and/or make your code more reliable. (The most obvious of those is probably the Array type, which because it contains the range/indices means you don't have to pass that sort of info in parameters.

> Also in the future I would like to have multiple "tasks" running, each with their "context", especially the db session.  I do believe these are good reasons for having a variable.

That is doable, I did it with a mock-up test and it worked pretty nicely... though personally I have had problems getting a good DB interface/binding up and running w/ Ada.