DrX

DrX, the good doctor, is a small object inspector for Ruby.
DrX is for newbies and gurus alike.
Instead of focusing on the contents of your object, DrX instead focuses on its object model. As a result, DrX is most suitable for programmers wishing to understand Ruby's object model better. It's especially adept at showing you how a "magical" library works (e.g., DataMapper).

Key features:

• See everything about a Ruby object: its 'klass', 'super', 'iv_tbl', 'm_tbl'. See your singletons with your very own eyes!
   
• Double-click a method to launch an editor and position the cursor on the exact line where the method is defined!

Installation

At your system prompt type:

gem install drx

Requirements 


require 'drx'

Errors and solutions:

1. MissingSourceFile: no such file to load -- tk
- require 'tcltklib' (install Tcl/Tk interface for Ruby)
2. RuntimeError: TkPackage can't find package tile
- install themed widget set provider library for Tk
3. RuntimeError: ERROR: Failed to run the 'dot' command. Make sure you have the GraphViz package installed and that its bin folder appears in your PATH.
- install rich set of graph drawing tools (GraphViz)

http://drx.rubyforge.org/