A modular, testable, Ruby debugger using some of the best ideas from ruby-debug, other debuggers, and Ruby Rails. Some of the core debugger concepts have been rethought. As a result, some of this may be experimental. This version works only with a MRI 1.8 and 1.9.2' See also rb-trepanning and rbx-trepanning versions that works with Rubinius. and a patched YARV 1.9.2.