Well, there is a REPL, but it's not that great: $ nim i >>> for i in 0..10: ... echo "Hello World"[0..i] ... H He Hel Hell

Well, there is a REPL, but it's not that great: $ nim i >>> for i in 0..10: ... echo "Hello World"[0..i] ... H He Hel Hell Hello Hello Hello W Hello Wo Hello Wor Hello Worl Hello World To use up/down keys, build the Nim compiler with "./koch boot -d:release -d:useGnuReadline" or run "rlwrap nim i" instead. Edit: It's even buggier than I remembered, best avoid it and use "nim -r c file" instead.