Hello. I have this singleton,

------------------------------------------------------
class Singleton
{
    private this() {}
    static __gshared typeof(this) instance = new this;
}
------------------------------------------------------

and I wonder if it has any weaknesses. Or is there a better way to make a Singleton?

,vladde,

On 02/13/2016 10:58 AM, Vladde Nordholm wrote:
> Hello. I have this singleton,
>
> ------------------------------------------------------
> class Singleton
> {
>      private this() {}
>      static __gshared typeof(this) instance = new this;
> }
> ------------------------------------------------------
>
> and I wonder if it has any weaknesses. Or is there a better way to make
> a Singleton?
>
> ,vladde,

David Simcha's DConf 2013 presentation has a singleton implementation at 27:55:

  https://www.youtube.com/watch?v=yMNMV9JlkcQ

Ali

On Saturday, 13 February 2016 at 19:32:33 UTC, Ali Çehreli wrote:
> David Simcha's DConf 2013 presentation has a singleton implementation at 27:55:
>
>   https://www.youtube.com/watch?v=yMNMV9JlkcQ
>
> Ali

Neat video! Watched the singleton section to end up watching the rest of the video. Anything every come of the std.patterns idea?

On Sat, 2016-02-13 at 18:58 +0000, Vladde Nordholm via Digitalmars-d- learn wrote:
> Hello. I have this singleton,
> 
> ------------------------------------------------------
> class Singleton
> {
>      private this() {}
>      static __gshared typeof(this) instance = new this;
> }
> ------------------------------------------------------
> 
> and I wonder if it has any weaknesses. Or is there a better way to make a Singleton?

Following the ACCU consensus: there is never, ever a good Singleton or reason to contemplate using one.

Obviously though there are some good ones: about dialogues in GUIs for example.

The good/evil-ness of Singleton is definitely in it's use: most people use Singleton wrongly, most uses should be banned. Hence the ACCU consensus.

It's all about coupling and mostly testability of code..

-- 
Russel. ============================================================================= Dr Russel Winder      t: +44 20 7585 2200   voip: sip:russel.winder@ekiga.net 41 Buckmaster Road    m: +44 7770 465 077   xmpp: russel@winder.org.uk London SW11 1EN, UK   w: www.russel.org.uk  skype: russel_winder

On Sunday, 14 February 2016 at 07:16:54 UTC, Russel Winder wrote:
> On Sat, 2016-02-13 at 18:58 +0000, Vladde Nordholm via Digitalmars-d- learn wrote:
>> [...]
>
> Following the ACCU consensus: there is never, ever a good Singleton or reason to contemplate using one.
>
> Obviously though there are some good ones: about dialogues in GUIs for example.
>
> The good/evil-ness of Singleton is definitely in it's use: most people use Singleton wrongly, most uses should be banned. Hence the ACCU consensus.
>
> It's all about coupling and mostly testability of code..

Thanks. I'm using David Simcha's singleton now.