1. Great startup time. Hello world took 0.015 seconds.
2. To get readline on REPL use: rlwrap ./janet -s
3. (os.exit) did not exit the REPL, but (os/exit) did. Looks like doc bug in GitHub README.md.
4. Syntax of for is different from Clojure and not as general. Instead of (for [x (range 10)] (print x) use (for x 1 10 (print x)).
5. Core API docs are at https://janet-lang.org/doc.html. Useful reference. Examples with each one (e.g. for) would be great.