each_foo.rb

include Enumerable
def each
  return Enumerator.new(self,:each) unless block_given?
  yield 1
  yield 2  
end
puts each.inject(:+).inspect
puts each{|x| x * x}.inject(:+).inspect



def each_foo
  return Enumerator.new(self,:each_foo) unless block_given?
  yield 1
  yield 2  
end
puts each_foo.inject(:+).inspect
puts to_enum(:each_foo){|x| x * x}.inject(:+).inspect