An example about defining method_missing()

defining_method_missing.rb

class User
  attr_accessor :first_name, :last_name, :birthday
  
  # method_missing() is passed 2 arguments: name of the missing method and arrays of its arguments
  # reference at the link: http://www.ruby-doc.org/core-2.1.0/BasicObject.html#method-i-method_missing
  def method_missing(name, *arg)
    puts "#{name} was called with arguments: #{arg.join(',')}. #{name} method not available."
  end
end

# Results
# user = User.new
# user.first_name => nil
# user.check_last_name("Nguyen", "Le") => check_last_name was called with arguments: Nguyen, Le. check_last_name method not available.