What was more interesting to me was this post to ruby-talk where he said:

I believe that the only way Ruby will ever be able to have the same level of tool support (of any kind, whether we're talking about code browsers, refactoring tools, or version control systems) that Smalltalk does is by making the same sacrifice that Smalltalk did: to completely avoid any form of code generation or macros. It's not an easy sacrifice to make - as someone used to Lisp, I found it very hard to come to terms with - but as long as the language is dynamic enough in other ways, I'm beginning to think it's worth making.

When you use exception handling, you have to think like the writer of a new programming language, not just an application developer.

Chris talked about some ways hes used resumable exceptions.