Compare Module to Binding Eval

module_vs_binding.rb

class S < Module

  def initialize
    extend self
  end

  def __binding__
    @binding ||= binding
  end

end


# Sample 1

s1 = S.new

s1.module_eval <<-END
  X = 10
  def x; 10; end
END

raise unless s1.x  == 10 rescue puts "s1.x  " + $!
raise unless s1::X == 10 rescue puts "s1::X " + $!


# Sample 2

s2 = S.new

eval(<<-END, s2.__binding__)
  X = 10
  def x; 10; end
  def y; 20; end
END

raise unless s2.x  == 10 rescue puts "s2.x  " + $!
raise unless s2.y  == 20 rescue puts "s2.y  " + $!
raise unless s2::X == 10 rescue puts "s2::X " + $!


# Sample 3

s3 = S.new

raise unless s3.x  == 10 rescue puts "s3.x  " + $!
raise unless s3.y  == 20 rescue puts "s3.y  " + $!
raise unless s3::X == 10 rescue puts "s3::X " + $!