borrow_rules.ko

// Demonstrates Kōdo's borrow rules: ref (shared) and mut (exclusive).
//
// - Multiple `ref` borrows of the same variable are allowed.
// - A `mut` borrow is exclusive: no other borrows may coexist.
// - A variable cannot be moved while any borrow is active.
//
// Compile and run:
//   kodoc build examples/borrow_rules.ko -o borrow_rules
//   ./borrow_rules

module borrow_rules {
    meta {
        purpose: "Demonstrate ref/mut borrow rules"
        version: "0.1.0"
    }

    // Takes a shared reference — caller retains ownership.
    fn read_value(ref x: String) {
        println(x)
    }

    fn main() {
        // Multiple ref borrows are OK.
        let msg: String = "hello borrow rules"
        read_value(msg)
        read_value(msg)

        // After two borrows, the value is still alive and usable.
        println(msg)
    }
}