Feature #12374
Updated by dsferreira (Daniel Ferreira) over 8 years ago
I propose to have a class `SingletonClass`, a subclass of the class `Class`, to which all singleton classes belong. It should be the owner of all the properties that are specific to singleton classes. Also, the methods defined on `Singleton` module should be moved to this class.
Reasons are as follows:
1. I was thinking that the reason #12084 hasn't been seen positively may be because the developers do not want to define a method only on limited instances of a class. If we have `SingletonClass`, the method `#instance` proposed in #12084 could be defined as an instance method of `SingletonClass`.
2. The way to introduce the singleton pattern using the `Singleton` module (http://ruby-doc.org/stdlib-2.3.0/libdoc/singleton/rdoc/Singleton.html):
~~~ruby
class A
include Singleton
# ...
end
~~~
is a bit unnatural and verbose. If we have `SingletonClass`, then we can define a singleton class more naturally:
~~~ruby
A = SingletonClass.new A.SingletonClass.new
~~~