The Devil's Typecasting in Ruby!

the_devils_typecasting.rb

require 'fiddle'

public def to_ptr
  Fiddle::Pointer.new Fiddle.dlwrap self
end

public def to!(klass)
  to_ptr[8, 8] = klass.to_ptr.ref[0, 8]
end

A, B = Class.new, Class.new
a = A.new
a # => #<A:0x000000012a9557b0>
a.to! B
a # => #<B:0x000000012a9557b0>