Those who are old Mac hands like myself might recall an old abandoned Apple project of the mid-90s, Dylan. Mike Lockwood has an interesting tale of the layoff of the guys who developed it. ‘The kind of layoff that could only happen at Apple.’ The article’s worth reading solely for the screenshot of the Dylan IDE the guys were working on. A long time ago I read an article (which I can unfortunately no longer find) by a fellow who wrote that source code needed to be more than just files, but actual living data, which could be manipulated in various useful ways; it looks as though the Dylan guys might have been headed in that direction.
To be honest, Dylan looks like a mostly warmed-over C/Algol/Pascal/&c. to me, in much the same way that many folks who construct their own languages end up with cyphers for English; it at least has closures (essentially, true first-class functions). I’d rather just go straight to using a Lisp, to be honest. Arc looks more promising.
The same site has a lot of other cool Apple tales.