Sorting exercise (Ch. 10) from "Learning to Program" by Chris Pine (2nd Edition)

Ch.10 Sorting Exercise

puts 'Please enter a list of words, separated by commas, that you would like to sort alphabetically.'

unsorted = gets.chomp.downcase.split(',')
sorted = []
 
def sorter unsorted, sorted
  if unsorted.length == 0
    return sorted 
  else
    smalls = unsorted.pop  #Biggie, Biggie, Biggie, can't you see? Sometimes your words just hypnotize me...
    unsorted.each do |tester| 
      if tester < smalls        
        unsorted.push smalls   
        smalls = tester         
      else 
        unsorted.push tester    
        sorted.push smalls
      end   
    end
  end
  sorter unsorted, sorted 
end
puts ' '
puts 'Here\'s your alphabetically sorted list! It\'s the bees knees.' 
puts unsorted.sort