// terms you write down are not just *statements* (executing code), but *expressions*
// (returning a value). This applies even to the body of entire functions!
+// ## Expression-based programming
// For example, consider `sqr`:
fn sqr(i: i32) -> i32 { i * i }
// Between the curly braces, we are giving the *expression* that computes the return value.
// Now that's already much shorter! Make sure you can go over the code above and actually understand
// every step of what's going on.
+// ## Inherent implementations
// So much for `vec_min`. Let us now reconsider `print_number_or_nothing`. That function
// really belongs pretty close to the type `NumberOrNothing`. In C++ or Java, you would
// probably make it a method of the type. In Rust, we can achieve something very similar