Thank you for the tip, Assaph. Sadly (for me), the pdf is in jap
Is there any kind soul who can provide an english version of the pdf?
There are a couple of examples of _why's pages:
http://whytheluckystiff.net/articles/rubyOneEightOh.html
And you can view the english documentation of dl.txt from CVS:
http://www.ruby-lang.org/cgi-bin/cvsweb.cgi/ruby/ext/dl/doc/dl.txt