Cross-loading ruby classes from multiple files

foo.rb

puts 'foo'

class Foo
  @@loaded ||= []
  @@loaded << 'foo.rb'

  def foo
    'Foo#foo in foo'
  end
  
  def bar
    'Foo#bar in foo'
  end

  load 'foo2.rb' unless @@loaded.include? 'foo2.rb'
  load 'foo3.rb' unless @@loaded.include? 'foo3.rb'
end

puts Foo.new.foo
puts Foo.new.bar
puts Foo.new.baz

foo2.rb

puts 'foo2'

class Foo
  @@loaded ||= []
  @@loaded << 'foo2.rb'

  def bar
    'Foo#bar in foo2'
  end
  
  def baz
    'Foo#baz in foo2'
  end
  
  load 'foo.rb' unless @@loaded.include? 'foo.rb'
  load 'foo3.rb' unless @@loaded.include? 'foo3.rb'
end

foo3-line-by-line-equivalent.rb

puts 'foo3'

Foo.class_eval '@@loaded ||= []'
Foo.class_eval '@@loaded << "foo3.rb"'

def Foo.baz
  'Foo#baz in foo3'
end

load 'foo.rb' unless Foo.class_eval('@@loaded').include? 'foo.rb'
load 'foo2.rb' unless Foo.class_eval('@@loaded').include? 'foo2.rb'

foo3.rb

puts 'foo3'

class Foo
  @@loaded ||= []
  @@loaded << 'foo3.rb'

  def baz
    'Foo#baz in foo3'
  end

  load 'foo.rb' unless @@loaded.include? 'foo.rb'
  load 'foo2.rb' unless @@loaded.include? 'foo2.rb'
end