hard-problem.rb

## Ruby Quiz #666

module Special
  CONSTANT = 1
end

module Base
end

class Specific
  include Base
  include Special

  # Don't touch anything above.
  # 
  # Goal: Define a method (foo) under the Base module which
  # references Specific::CONSTANT and accepts a block with yield:
  # 
  #   module Base
  #     def foo
  #       CONSTANT + yield
  #     end
  #   end
  #
  # Ignore the fact that Special exists. The constant could be in any included module.
  
  # Failed attempts:
  
  # The CONSTANT lookup doesn't work at all.
  module ::Base
    def foo
      CONSTANT + yield
    end
  end
  
  # The CONSTANT lookup doesn't work in 1.9.
  ::Base.class_eval do
    def foo2
      CONSTANT + yield
    end
  end
  
  # The CONSTANT lookup works, but the yield doesn't.
  ::Base.send(:define_method, :foo3) do
    CONSTANT + yield
  end
end


## Examples:

p ((Specific.new.foo { 2 } rescue $!))
p ((Specific.new.foo2 { 2 } rescue $!))
p ((Specific.new.foo3 { 2 } rescue $!))

The point is: All Tilt know is that the Ruby code could be CONSTANT + yield, so it can't really modify that (without parsing it and doing lots of checks, which is out of scope of Tilt).