class AccessViolationException<Exception
end

class PublicAPI
  def initialize(target)
    @@api||={}
    @target=target
    this=self
    @target.class_eval{
      @@_api=this
      def self.api(*s)
        @@_api.addAPI(self,*s)
      end
      def api(*s)
        @@_api.api(self,*s)
      end
    }
  end
  def addAPI(this,*s)
    @@api[this]||=[]
    @@api[this]+=s
  end
  def api(object,*s)
    if @@api[object.class].member?(s[0])
      object.send(*s)
    else
      raise AccessViolationException.new      
    end
  end
end

def publicAPI
  PublicAPI.new(self)
end