// Feature 1 — value-position pack projection: `xs.<method>` projects a
// (zero-arg) protocol method over every element into a TUPLE of the per-element
// results. For a parameterised `Box(T)`, each element's method returns its own
// `T`, so the projected tuple is heterogeneous.
//
//   xs.get  ≈  (xs[0].get(), xs[1].get())

#import "modules/std.sx";

Box :: protocol(T: Type) {
    get :: () -> T;
}

IntCell :: struct { v: i64; }
StrCell :: struct { s: string; }
impl Box(i64) for IntCell { get :: (self: *IntCell) -> i64 => self.v; }
impl Box(string) for StrCell { get :: (self: *StrCell) -> string => self.s; }

show :: (..xs: Box) -> void {
    vals := xs.get;                       // tuple (i64, string)
    print("0={} 1={}\n", vals.0, vals.1);
}

main :: () -> i32 {
    show(IntCell.{ v = 42 }, StrCell.{ s = "hi" });
    show(StrCell.{ s = "x" }, IntCell.{ v = 7 });   // order swapped → (string, i64)
    0
}