// Feature 1 / Step 0.4 — tuple baseline probe (gate for Decision 2:
// "tuples are first-class for pack storage").
//
// This file is the audit artifact: it exercises every tuple operation the
// canonical `Combined`/`map` body relies on, EXCEPT the two pack/tuple
// projection+spread sugars that are themselves Feature 1 work (documented
// as gaps at the bottom). Everything here RUNS today.
//
// Run:  ./zig-out/bin/sx run examples/probes/tuple-baseline.sx

#import "modules/std.sx";

Listenable :: struct { value: s64; }      // stand-in element struct
Combined   :: struct { sources: (s32, s32); }  // tuple-typed field (Decision 2)

swap :: (a: s64, b: s64) -> (s64, s64) { (b, a) }
fst  :: (t: (s64, s64)) -> s64 { t.0 }

main :: () -> s32 {
    // ── Block A — primitives (WORKS) ───────────────────────────────
    pair := (40, 2);                       // inferred positional
    print("A.idx     {} {}\n", pair.0, pair.1);
    named := (x: 10, y: 20);               // named + numeric access
    print("A.named   {} {} {}\n", named.x, named.0, named.1);
    one := (42,);                          // 1-tuple
    print("A.one     {}\n", one.0);
    a : s64 = pair.0;                      // element into typed local
    print("A.local   {}\n", a);

    // ── Block B — storage in a struct field (WORKS; core of Decision 2)
    c : Combined = ---;
    c.sources = (7, 9);                    // assign tuple value to field
    print("B.field   {} {}\n", c.sources.0, c.sources.1);

    // ── Block C — return / pass / operators (WORKS) ────────────────
    s := swap(1, 2);
    print("C.ret     {} {}\n", s.0, s.1);
    print("C.pass    {}\n", fst((11, 22)));
    print("C.eq      {}\n", (1, 2) == (1, 2));
    cc := (1, 2) + (3, 4);
    print("C.concat  {} {}\n", cc.0, cc.3);
    print("C.mem     {}\n", 3 in (1, 2, 3));
    0
}

// ── GAPS (Feature 1 work — intentionally NOT exercised above) ──────
//
//   G1. Tuple field projection across elements:
//         t := (Listenable.{value=1}, Listenable.{value=2});
//         v := t.value;        // expected: (1, 2)   — Decision 3 "tuple.field"
//       Today: `error: field 'value' not found on type 'tuple'`.
//       Needed by canonical `self.sources.value`.
//
//   G2. Tuple spread into call args:
//         p := (10, 20);
//         add(..p);            // expected: add(10, 20) — Decision 3 "..tuple"
//       Today: lowers to one `undef` arg → LLVM arity verification failure.
//       Needed by canonical `mapper(..sources.value)` and `(..sources)`.
//
// Both are already scheduled: parsing in Phase 1.2 (PackExpansion node covers
// `(..pack)` / `..pack.field`), sema in Phase 2.3 ("tuple-spread parallels").
// No separate Feature 1.5 needed — see Step 0.4 triage in CHECKPOINT-LANG.md.