K lang was featured here a few months ago: https://news.ycombinator.com/item?id=11561573
For anyone else just starting out, I suggest using readline with the REPL: `rlwrap q`. It gives you history, search, familiar line editing commands, etc.
http://johnearnest.github.io/ok/mobile.html
Try entering:
pl[.5*!50;sin]