Sorting method found in Chris Pine's "Learning to Program"

sorting.rb

def sort arr 
  rec_sort arr, []
end

def rec_sort unsorted, sorted 
  if unsorted.length <= 0
    return sorted 
  end
# So if we got here, then it means we still # have work to do.

smallest = unsorted.pop
still_unsorted = []
unsorted.each do |tested_object| 
  if tested_object < smallest
      still_unsorted.push smallest
      smallest = tested_object
  else
      still_unsorted.push tested_object
    end 
  end
        #  Now "smallest" really does point to the
        #  smallest element that "unsorted" contained,
        #  and all the rest of it is in "still_unsorted".
  sorted.push smallest
  rec_sort still_unsorted, sorted
end
puts(sort(['can','feel','singing','like','a','can']))