When using reader conditionals, evaluating a reader conditional in a vanilla command-line REPL (not nRepl or anything like that) results in a "Conditional read not allowed" error message.
Loading the whole file with load-file works as expected.
This breaks the very normal workflow of eval-ing forms from a *.cljc file in a Clojure repl using (e.g.) inferior lisp.
Approach: clojure.main/repl (also used by swank I think) enables reader conditionals at the REPL.
Looks/works great for me - I quite literally wrote the exact same patch before talking w/ Luke today about this.