BLACK MAGIC IN RUBY!

1.black_magic_converting_a_ruby_object_to_a_string.rb

# ==========  READ THIS LAST  ==========
# It prob won't make sense, anyway, as there's a lot of implicit nuance.
# I don't even fully understand the flags I'm setting it to.
public def to_s!
  require 'fiddle'
  Fiddle::Pointer.new(2*object_id)[0, 16] =
    [5373957, 2*String.object_id].pack('q2') # flags & class
end

# ==========  SETUP  ==========
# An instance of a class with one ivar
class SomeClass
  attr_accessor :some_var
end
some_obj = SomeClass.new
some_obj.some_var = 1205329432411354807 # found with: "Omg wat!".unpack("q")[0] >> 1

# ==========  BLACK MAGIC  ==========
some_obj # => #<SomeClass:0x007fa0f3032500 @some_var=1205329432411354807>
some_obj.to_s!
some_obj # => "omg wat!"

2.black_magic_bind_a_method_to_an_instance_of_another_class.rb

require 'fiddle'
class Method
  def self=(obj)
    ptr = Fiddle::Pointer.new object_id << 1
    ptr = Fiddle::Pointer.new ptr[040, 8].unpack('q')[0]
    ptr[0, 8] = [obj.object_id*2].pack('q')
  end
end

class A
  def initialize(a)
    @a = a
  end
  def to_h
    instance_variables.map { |v| [v, instance_variable_get(v)] }.to_h
  end
end

class B
  def initialize(b)
    @b = b
  end
end

# JavaScripters won't be impressed, but you can't normally do this in Ruby!
a    = A.new 'aye'     # => #<A:0x007fcd091513b8 @a="aye">
b    = B.new 'bee'     # => #<B:0x007fcd091510c0 @b="bee">
to_h = a.method :to_h  # => #<Method: A#to_h>
to_h.call              # => {:@a=>"aye"}
to_h.self = b
to_h.call              # => {:@b=>"bee"}

3.black_magic_bindable_procs.rb

require 'fiddle'
class Proc
  def bind(obj)
    bound = dup
    ptr = Fiddle::Pointer.new bound.object_id << 1
    ptr = Fiddle::Pointer.new ptr[040, 8].unpack('q')[0]
    ptr[0, 8] = [obj.object_id*2].pack('q')
    bound
  end
end


A = Class.new { define_method(:initialize) { |a| @a = a } }
B = Class.new { define_method(:initialize) { |b| @b = b } }

to_h = Proc.new do
  instance_variables.map { |v| [v, instance_variable_get(v)] }.to_h
end

a = A.new 'aye'  # => #<A:0x007fa794001480 @a="aye">
b = B.new 'bee'  # => #<B:0x007fa794001188 @b="bee">
[to_h.bind(a), to_h.bind(b)].map &:call  # => [{:@a=>"aye"}, {:@b=>"bee"}]