Functions

Basics

fn add(a: i32, b: i32): i32 {
    return a + b
}

fn greet(name: string): void {
    print("hello, ", name)
}

Generic functions

fn identity<T>(x: T): T {
    return x
}

let n = identity(42)       // T inferred as i64
let s = identity("hello")  // T inferred as string

Built-in functions

Function	Description
print(args...)	Print with trailing newline
exit(code)	Exit the process
jsonStringify(val)	Serialize a struct to JSON

Builtins spelled with an @ (@embedFile, @targetOs) run while compiling; they are listed under compile-time builtins.

Reference parameters

A parameter typed &T borrows its argument and &mut T may change it. The call passes a shared borrow bare, length(s), and marks a mutable one, double(&mut n). Ownership has the rules.