函数

fn gcd(a: u32, b: u32) -> u32 {
    if b > 0 {
        gcd(b, a % b)
    } else {
        a
    }
}

fn main() {
    println!("gcd: {}", gcd(143, 52));
}
  • 类型跟随在声明的参数后（与某些编程语言相反），然后是返回类型。
  • The last expression in a function body (or any block) becomes the return value. Simply omit the ; at the end of the expression. The return keyword can be used for early return, but the "bare value" form is idiomatic at the end of a function (refactor gcd to use a return).
  • Some functions have no return value, and return the 'unit type', (). The compiler will infer this if the return type is omitted.
  • Overloading is not supported -- each function has a single implementation.
    • 始终采用固定数量的参数。不支持默认参数。宏可用于支持可变函数。
    • Always takes a single set of parameter types. These types can be generic, which will be covered later.