Diablo is under development and is not functional yet.
If Diablo is not already installed, follow the installation guide.
$ diablo
[#] Diablo REPL vX.X.X
dbl> print("Hello World");
Hello World
dbl> fn foobar(foo, bar) { print(foo + bar); }
dbl> foobar(1.1, 2.2);
3.3
$ diablo foobar.dbl
Hello World