// Variadic heterogeneous type packs — step 4A end-to-end
// smoke. Exercises the FULL chain step 5's generic
// `Into(Block)` impl needs:
//
//   1. A pack-fn that passes its bound `$args` to a builder
//      via `#run` / `#insert` (here `#run` for simplicity).
//   2. The builder receives a `[]Type` slice and walks it,
//      calling `type_name(list[i])` per position.
//   3. `type_name(list[i])` is the DYNAMIC form — the index_expr
//      argument can't be statically resolved at lower time, so
//      the lowering emits a `callBuiltin(.type_name, ...)` that
//      the interp's arm handles by reading the runtime
//      `Value.type_tag(TypeId)` and returning the per-position
//      name.
//
// The smoke demonstrates that step 4's full surface — bare
// `$args` (whole pack as []Type) + dynamic reflection
// intrinsics + per-position type discovery at interp time —
// hangs together end-to-end. This is the foundation step 5's
// builder-driven generic Into(Block) impl rests on.

#import "modules/std.sx";
#import "modules/build.sx";

// Generic "describe pack" builder. Receives the pack as
// []Type, returns a joined string with each type's name.
describe :: (..$args) -> string {
    list := $args;
    s := "[";
    i : i64 = 0;
    while i < list.len {
        if i > 0 { s = concat(s, ", "); }
        s = concat(s, type_name(list[i]));
        i = i + 1;
    }
    s = concat(s, "]");
    return s;
}

run_all :: () {
    print("{}\n", describe());                        // []
    print("{}\n", describe(42));                       // [i64]
    print("{}\n", describe(42, "hi"));                 // [i64, string]
    print("{}\n", describe(true, 3.14, "x", 99));       // [bool, f64, string, i64]
}
#run run_all();

main :: () { print("rt\n"); }