def word=(word)
      add_weight :count, :letter, word.length
      add_weight :first, :letter, word[0]
      (word.length - 1).times { |l| add_weight :next, word[l], word[l.succ] }
      add_weight :last, word[-2], word[-1]
    end
def word=(word)
      add_weight :count, :letter, word.length
      add_weight :first, :letter, word[0]
      (word.length - 1).times { |l| add_weight :next, word[l], word[l.succ] }
      add_weight :last, word[-2], word[-1]
    end
Analyze word

 Adds weights for first, next and last letters and letter count

 @param [String] word