I am currently designing/building a programming editing environment around proportional fonts (specifically, some kind of sans serif). You can see the effect in this essay I submitted sometime back on hackernews:
Its been fun getting font metrics working right (given a custom editor) and getting key-up and key down to work correctly, but overall, I think this is the future, especially in richer editing environments.
I really like this, and while I wouldn't code in just any font, this one seems to lend itself. Only nitpick would be breathing room around parentheses and "." in method calls. Right now it's a bit tight. Love this article though, definitely some cool stuff going on in this space.
http://research.microsoft.com/en-us/people/smcdirm/liveprogr...
Its been fun getting font metrics working right (given a custom editor) and getting key-up and key down to work correctly, but overall, I think this is the future, especially in richer editing environments.