Ruby method_missing

ruby-method_missing.rb

class Roman
  def self.method_missing name, *args
    roman = name.to_s
    roman.gsub!("IV", "IIII")
    roman.gsub!("IX", "VIIII")
    roman.gsub!("XL", "XXXX")
    roman.gsub!("XC", "LXXXX")
    (
      roman.count("I") +
      roman.count("V") * 5 +
      roman.count("X") * 10 +
      roman.count("L") * 50 +
      roman.count("C") * 100
    )
  end
end
puts Roman.X    # 10
puts Roman.XC   # 90
puts Roman.XII  # 12
puts Roman.IX   # 9