Re: 'withing' problem

["Matthew Heaney" <mheaney@on2.com>]

"Simon Wright" <simon@pushface.org> wrote in message
news:x7vy9lbxih0.fsf@smaug.pushface.org...
> I think that people looking at this model, perhaps for the purpose of
> maintaining code written to implement it, need to have a very clear
> idea of how the code will look.

My philosophy is, if you want to have a good idea how the code will look,
then you should look at the code...  In any case, you should just ignore the
forward declaration package, as it's just syntactic overhead that has no
bearing on your model of the problem.

> It's a Bad Thing if you need to make arbitrary decisions to break
> cycles.

You haven't explained why arbitrary decisions are bad, so this isn't a very
cogent argument, which just reduces to "I don't like it, so it's bad."

And besides, this solution is no different from other areas of the language.
For example, if you want to declare a recursive pair of subprograms, then
you have to forward declare one of them (and it's arbitrary which one):

declare
   procedure Op1;
   procedure Op2 is
   begin
      Op1;
   end;
   procedure Op1 is
   begin
      Op2;
   end;
begin
   null;
end;


> What would be even worse would be to have a framework code generator
> that applied heuristics to break cycles. I imagine that it wouldn't
> take much for such heuristics to make the opposite decision for minor
> model changes (remember that very few models are as simple as this
> one!)

Let's concentrate on real problems.  John Volan couldn't figure out how to
declare two mutually dependent abstractions in two separate packages.  I
showed how to do this.  Problem solved.