Functions

fn add(x: i32, y: i32) -> i32 {
    return x +% y;
}

// No return type means the unit type ().
fn shout(msg: str) {
    println(msg);
}

// `pub` for cross-file visibility (the default is module-private).
pub fn answer() -> i32 { return 42; }

Every function body must end with return EXPR;. There is no implicit tail return at the function level (the rule is E0333). Block expressions can still be tail expressions inside a return or a let:

fn classify(n: i32) -> i32 {
    return if n < 0 { -1 } else if n == 0 { 0 } else { 1 };
}

Generics use square brackets, not angle brackets (see Ownership for how arguments are passed):

fn identity[T](x: T) -> T { return x; }
fn max[T: Ord](a: T, b: T) -> T { ... }

There is no function overloading. A name has one signature, period. That is what lets a reader, or a model, resolve a call to exactly one definition.