Eric Hodges is
I've started to write my own Lisp implementation in Java. AreDesignPatternsMissingLanguageFeatures convinced me (apparently subconsciously) that I need features only Lisp can provide. I've been learning Lisp with clisp, but my inability to find a decent GUI package for Windows led me to the (perhaps insane) conclusion that I'd be better off writing my own Lisp in Java so I could use the Swing library.
This is the first time I've tried to learn a language by implementing it. So far it's been a lot of fun, but I haven't reached macros yet. The sense of "turtles all the way down" is quite visceral, even when I'm writing Java code that emulates bits that ought to be Lisp code. I wish I'd done this years ago. -- EH