[Tutor] Tips

[Albert-Jan Roskam]

----- Original Message -----

> From: Alex Kleider <akleider at sonic.net>
> To: tutor at python.org
> Cc: 
> Sent: Thursday, June 19, 2014 8:10 PM
> Subject: Re: [Tutor] Tips
> 
> On 2014-06-18 18:37, Steven D'Aprano wrote:
>>  Python tries very hard to ensure that every module is loaded only once.
>>  (There are circumstances where you can fool it, but they're rare.) 
>>  Since
>>  the module holds state (variables) and behaviour (functions), modules
>>  perform the same sort of role as classes, so a module which is loaded
>>  once is very similar to a singleton instance. In other words, if you
>>  want a class to implement singleton behaviour, you have to work at it.
>>  But if you shift the functionality from the class into a module, Python
>>  gives you singleton behaviour for free.
>> 
>>  But if you're not sure why anyone would want a singleton instance, I
>>  agree with you: most (but not all) uses of singletons are unnecessary.
> 
> The idea of a singleton class is new to me as is this comparison of 
> class vs module.
> Can anyone suggest a place to turn for more discussion of the topic?
> thks, alexK

Maybe this (it's about Singleton and Borg): http://stackoverflow.com/questions/1318406/why-is-the-borg-pattern-better-than-the-singleton-pattern-in-python