appleize.rb

module StringAppleization
  refine String do
    def appleize
      split(' ').map do |word|
        appleize_word(word)
      end.join(' ')
    end

    private

    def appleize_word(word)
      first_letter = word[0]
      rest = word[1..-1]

      case first_letter
      when 'i'
        first_letter + rest.capitalize
      when 'I'
        first_letter.downcase + rest.capitalize
      else
        word.capitalize
      end
    end
  end
end

class AppleizedSentence
  using StringAppleization

  def initialize(sentence)
    @sentence = sentence
  end

  def i_sentence
    sentence.appleize
  end

  private

  attr_reader :sentence
end

puts AppleizedSentence.new("this iphone is awesome").i_sentence