gistfile1.rb

module Austin
  
  Guess = Struct.new(:letter, :frequency_ratio, :word_frequency_ratio) do
    def <=>(guess)
      weight <=> guess.weight
    end
    
    def weight
      2 * word_frequency_ratio + frequency_ratio
    end
    
    def update_ratios(word_list)
      self.frequency_ratio = word_list.join('').percentage_of(letter)
      self.word_frequency_ratio = word_list.percentage_with(letter)
    end
  end
    
  class HangmanGame
    def initialize(word_list)
      @word_list = word_list
      @guesses = ('a'..'z').map { |letter| Guess.new letter }
    end
    
    def guess(word)
      self.word = word
      @guesses.sort!.pop.letter
    end
    
    def word=(new_word)
      if @word != new_word
        @word = new_word
        update_word_list
        update_guesses
      end
    end
    
    def update_word_list
      word_pattern = /^#{@word.gsub('_', "[a-z]")}$/
      @word_list = @word_list.select { |word| word_pattern === word }
    end
    
    def update_guesses
      @guesses.each { |g| g.update_ratios @word_list }
    end
    
  end
  
  class Austin
    attr_writer :word_list

    def new_game(guesses_left)
      @game = HangmanGame.new(@word_list)
    end
    
    def guess(word, guesses_left)
      @game.guess(word)
    end
    
    def incorrect_guess(guess); end
    def correct_guess(guess); end
    def fail(reason); end
    def game_result(result, word); end
  end
end

class String
  def percentage_of(letter)
    count(letter).to_f / size
  end
end

class Array
  def percentage_with(letter)
    select { |word| word.include?(letter) }.size.to_f / size
  end
end