Referring to the type of value of an enum in the enum's class methods

Help & Support
4

It looks like you want the #value method to get the integer value out of the enum instance.

enum AAA : Int32
  Aaa
  Bbb
  Ccc
  
  def foo
    value.foo
  end
end

struct Int32
  def foo
    "foo#{self}"
  end
end

p AAA::Aaa.foo # => "foo0"
p AAA::Bbb.foo # => "foo1"
p AAA::Ccc.foo # => "foo2"

But as @asterite said, avoid adding new methods to built-in types, especially primitive types. That will cause issues down the line.