it was very confusing for me to find out that @variable may mean 2 very different things. No, it doesn’t. Classes are objects just like any other object. They can have instance variables just like any other object. They can have instance methods just like any other object. In fact, unlike Java, which has three … Read more
A class variable (@@) is shared among the class and all of its descendants. A class instance variable (@) is not shared by the class’s descendants. Class variable (@@) Let’s have a class Foo with a class variable @@i, and accessors for reading and writing @@i: class Foo @@i = 1 def self.i @@i end … Read more
Instance variable on a class: class Parent @things = [] def self.things @things end def things self.class.things end end class Child < Parent @things = [] end Parent.things << :car Child.things << :doll mom = Parent.new dad = Parent.new p Parent.things #=> [:car] p Child.things #=> [:doll] p mom.things #=> [:car] p dad.things #=> [:car] … Read more