array.rb

class Array
  undef :each

  def each
    return to_enum(__callee__) unless block_given?

    size.times do |i|
      yield self[i]
    end
  end
end



arr = [1,2,3]

arr.each do |el|
  p [:each, el]
end


enum = arr.each
p [:enum, enum.inspect]

p [:next, enum.next.inspect]
p [:next, enum.next.inspect]
p [:next, enum.next.inspect]
p [:next, enum.next.inspect]