aaa.rb

module SelfStorage
  # get :: IO [String]
  def self.get
    raise unless defined? DATA
    DATA.readlines.map(&:chomp)
  end

  # append :: [String] -> IO ()
  def self.append(ss)
    raise unless defined? DATA
    File.open(__FILE__, 'a') {|io|
      io.puts ss
    }
  end

  # rewrite :: [String] -> IO ()
  def self.rewrite(ss)
    raise unless defined? DATA
    File.open(__FILE__, 'r+') {|io|
      nil until io.gets.chomp == '__END__'
      io.puts ss
      io.truncate io.pos
    }
  end
end

#p SelfStorage.get
#SelfStorage.append(['1123', :ww])
#SelfStorage.rewrite(%w[jdsaf])
__END__
jdsaf