V.1 Hello world

// src/main.oxl — the root module of the package; main is the entry point (§2.4)
fn main() io {                        // io is an effect: we read the environment and write to stdout
  let name = env("USER") ?? "world"   // env returns str?; ?? substitutes a value on none
  print("Hello, {name}!")             // {name} is interpolation, calls Show.show
}

$ oxl new hello && cd hello && oxl run
Hello, ann!