Re: [Vala] Singleton and reference count

[Victor Manuel Jáquez Leal <ceyusa gmail com>]

> > public class Singleton<G>
> > {
> >   public G instance {get; private set; }
> >
> >   public Singleton(owned G instance)
> >   {
> >     _instance = (owned) instance;
> >   }
> > }
> >
> > public class Prefs
> > {
> >   internal Prefs ()
> >   {
> >     stdout.printf ("constructor\n");
> >   }
> >
> >   public void do_something()
> >   {
> >     stdout.printf("Doing something...\n");
> >   }
> >
> >   ~Prefs ()
> >   {
> >     stdout.printf ("destruction\n");
> >   }
> > }
> >
> > Singleton<Prefs> preferences;
> >
> > public static void main (string[] args)
> > {
> >   preferences = new Singleton<Prefs>(new Prefs());
> >
> >   preferences.instance.do_something();
> >   preferences.unref();
> > }
>
> What's the point of this code? The Singleton class is redundant, you can
> do exactly the same just by storing a single instance of Prefs in a
> global variable. That's not a singleton.
> Note: you should use preferences = null, rather than unref()

I guess is a way to have a generic way to add the singleton behavior
to a class, just as this proposed (and rejected) utility in boost:
http://torjo.com/tobias/

vmjl