Why cant there be classes inside methods in Ruby?

Question

Can I create Ruby classes within functions bodies ? I seem to be getting error which tells me its not allowed but I think it should be as classes are too objects here.

class A
    def method
        class B
        end
    end
end

This fails with error 'class definition inside method body. If we cant, why cant we create classes inside methods ?

Answer 1

you can create classes, but you cannot assign constants from inside a method.

this example works:

class A
  def a
    b = Class.new
    def b.xxx
      "XXX"
    end
    b
  end
end

a = A.new.a
p a         # #<Class:0x7fa74fe6cc58>
p a.xxx     # "XXX"