--- append_features(module_or_class)

    ⥸塼(뤤ϥ饹) self εǽɲäޤ
    Υ᥽åɤ Module#include μΤǤꡢinclude 
    Ruby ǽ񤯤ȰʲΤ褦Ǥޤ
        def include(*modules)
          modules.each {|mod|
            # append_features ϥץ饤١ȥ᥽åɤʤΤ
            # ľ mod.append_features(self) ȤϽ񤱤ʤ
            mod.__send__ :append_features, self
            # 1.7 ʹߤϰʲιԤ¹Ԥ
            # mod.__send__ :included, self
          }
        end

    self ֤ޤ

