Pointers

Pointers in helix are similar to pointers in C and C++. They are used to store the memory address of a variable.

fn main() {
    var my_int: i32 = 42;
    var my_int_ptr: *i32 = &my_int; // Get the address of my_int

    std::print(f"Value of my_int: {my_int}"); // Output: 42
    std::print(f"Address of my_int: {my_int_ptr}"); // Output: Address of my_int
    std::print(f"Value at my_int_ptr: {*my_int_ptr}"); // Dereference pointer to get value: 42

    // Modify the value using the pointer
    (*my_int_ptr) = 100; // we need to put the deref in parentheses since otherwise the oprator precedence would try to do `*my_int_ptr = 100` as `*(my_int_ptr = 100)` (its very broken)
    std::print(f"New value of my_int: {my_int}"); // Output: 100
}

Pointers can also be null, which means they do not point to any valid memory address.

fn main() {
    var my_null_ptr: *i32 = &null; // Create a null pointer

    if (my_null_ptr == &null) {
        std::print("my_null_ptr is a null pointer");
    } else {
        std::print(f"Value at my_null_ptr: {*my_null_ptr}");
    }
}

We do have refrences in helix but try avoiding them.

fn main() {
    var my_int: i32 = 42;
    var my_int_ref: ref!(i32) = my_int; // Get a reference to my_int

    std::print(f"Value of my_int: {my_int}"); // Output: 42
    std::print(f"Value of my_int_ref: {my_int_ref}"); // Output: 42
    my_int_ref = 100; // Modify the value using the reference
    std::print(f"New value of my_int: {my_int}"); // Output: 100
}

/// Rvalue references are also supported
fn main() {
    var my_int: i32 = 42;
    var my_int_rref: mref!(i32) = std::move(my_int); // Get an rvalue reference to my_int

    std::print(f"Value of my_int_rref: {my_int_rref}"); // Output: 42
    my_int_rref = 100; // Modify the value using the rvalue reference
    std::print(f"New value of my_int_rref: {my_int_rref}"); // Output: 100
}

Also both ref! and mref! can only be used in the context of types.