[ruby-core:5420]
ttp://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/5420

> Sydney is an experimental fork of ruby 1.8.2 that implements a number
> of new features, such as Native OS threads, Backtrace and Frame
> objects, more event hooks, and many more.

試してないけど、>>199 がお望みの Ruby かもしれませんよ。