Bob without if's and case

bob.rb

class Bob
  def hey(phrase)
    think_about(heard(phrase)).respond
  end

  def heard(phrase)
    String(phrase)
  end

  def think_about(might_have_heard)
    THOUGHTS.find(-> { Default }) { |thought| thought.heard?(might_have_heard) }
  end

  class << Silent = Object.new
    def heard?(other)
      other.empty?
    end

    def respond
      "Fine. Be that way."
    end
  end

  class << Question = Object.new
    def heard?(other)
      other.end_with?("?")
    end

    def respond
      "Sure."
    end
  end

  class << Shout = Object.new
    def heard?(other)
      other == other.upcase
    end

    def respond
      "Woah, chill out!"
    end
  end

  class << Default = Object.new
    def respond
      "Whatever."
    end
  end
  THOUGHTS = [Silent, Question, Shout]
end

Oops, I apparently wasn't logged in when I posted this.

please comment on this one instead. https://gist.github.com/adkron/6148836