Everything in Ruby is an object, including the class. When you create a new class, you are basically creating an instance of class Class. Ruby even allows you to override the new method on a class, allowing you to customize the creation of all objects.
class Person
# person-specific code
end
When Ruby encounters the above code, it creates an instance of type Class. It then assigns this object to a global constant named Person.
When you call Person.new to create a new person, the #new method on the Class is called, by default. However, like everything in Ruby, you can override it.
class Class
alias create new
def new(*args)
puts "Creating a new #{self.name}"
create(*args)
end
end
class Person; end
ak = Person.new
# Creating a new Person
# #<Person:0x00007fde9e869280>
puts ak
Knowing that classes are instances of Class allows you to dynamically create classes on the fly.
Person = Class.new do
def greet
"hello"
end
end
ak = Person.new
puts ak.greet # hello