In the Wild

One of the best ways to gain some insight into how your Ruby implementation works is to look into how to extend it. Every Ruby implementation allows you to add features to the native implementation. Since you need some understanding of the implementation in order to extend it, the “how to extend Ruby” documentation is a great source of insight into how that Ruby works. Both the MRI and YARV source code come with a README.EXT file^[8] that does a good job of explaining the basics.

^[8] Yes, that suffix is .EXT, as in “extension,” not .TXT.

The JRuby project has an entire section of its website devoted to explaining how JRuby works. As I write this the URL for this documentation is www.kenai.com/projects/jruby/pages/Internals. It is well worth a look.