const Foo = struct {
    bar: usize = 42,

    fn modifySelf(self: Foo, new_bar: usize) void {
        self.bar = new_bar;
    }

    fn returnModifiedSelf(self: Foo, new_bar: usize) Foo {
        return Foo{
            .bar = new_bar,
        };
    }
};

pub fn main() void {
    var foo = Foo{};

    // This line doesn't compile since parameters are immutable
    // foo.modifySelf(21);

    // This works but is a little awkward IMO — Is this the idiomatic way in Zig?
    foo = foo.returnModifiedSelf(21);
}