I've begun working on implementing SourceMaps for ClojureScript. For an overview of SourceMaps, see: http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/ For discussion of the feature in ClojureScript, see: https://groups.google.com/d/topic/clojure-dev/zgmXO2iM1JQ/discussion
In order to produce accurate source maps, I need column information in addition to line information from the Clojure reader.
I've made the necessary enhancement to LispReader, etc. but have some cleanup and testing left to do. I'd also like a sanity check from the core team before attaching a formal patch. You can find my work in progress here: https://github.com/brandonbloom/clojure/compare/columns