It was complicated, but at one point I was so in love with Arc that I wanted to give it a real shot at taking over the world. It seemed like a necessary change to make, since the moment someone brought up dead links as a slight against arc, I could point to the change and say, "Already fixed!"

(I made a few other improvements, like having accurate line numbers in error messages, and a clojure-style REPL for emacs: https://www.youtube.com/watch?v=3v1KpEmuPeM)