class MyClass
def sayHello
return "hello from MyClass"
end
def sayGoodbye
return "Goodbye from MyClass"
end
end
class MyOtherClass < MyClass
def sayHello
return "Hello from MyOtherClass"
end
def sayGoodbye
return super << "and also from MyOtherClass"
end
def to_s
return "I am an instance of the #{self.class} class"
end
end
可以作为ruby语言的一大特性