2011-02-15 メモ http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-dev/33628 http://znz.s1.xrea.com/t/?date=20090102#p01 http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-dev/37679 http://redmine.ruby-lang.org/issues/show/973