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sx/examples/packs/0543-packs-canonical-map.sx
agra 66bdc70bf1 test: group examples into per-category folders
Move examples/*.sx and their expected/ snapshots into per-category
subfolders (examples/<category>/...). Folder = leading filename token,
with ffi-objc/ffi-jni kept whole; filenames are unchanged. The corpus
runner and LSP sweep now discover each category's expected/ dir, while
issues/ stays flat. Example 1058's repo-root-relative companion import
is made file-relative. Path strings embedded in 164 snapshots were
regenerated (path-only changes). Test-layout docs in CLAUDE.md updated.
2026-06-21 14:41:34 +03:00

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// Phase 6 — the canonical heterogeneous `map`, end to end. A pack-fn whose
// return type `$R` is inferred from the mapper's closure return:
// - `mapper: Closure(..sources.T) -> $R` types the lambda's params from the
// projected pack element types, and its body (`a + b`) drives `$R`.
// - `$R` is inferred at the call site from the lowered mapper's closure ret,
// bound into the mono (`-> VL($R)` ⇒ `VL(i64)`, `Combined($R, ..)` ⇒
// `Combined(i64, ..)`), and folded into the mangle.
// - `(..sources)` materializes the pack into the `(..VL(Ts))` field (per-element
// erase) and `mapper(..sources.get)` projects+spreads; `xx c` erases the
// generic-struct instance to `VL(i64)` via the generic impl's monomorphized
// thunk.
#import "modules/std.sx";
VL :: protocol(T: Type) { get :: (self: *Self) -> T; }
IntCell :: struct { v: i64; }
impl VL(i64) for IntCell { get :: (self: *IntCell) -> i64 => self.v; }
Combined :: struct($R: Type, ..$Ts: []Type) {
sources: (..VL(Ts));
value: $R;
}
impl VL($R) for Combined($R, ..$Ts) { get :: (self: *Combined) -> $R => self.value; }
map :: (mapper: Closure(..sources.T) -> $R, ..sources: VL) -> VL($R) {
c : Combined($R, ..sources.T) = ---;
c.sources = (..sources);
c.value = mapper(..sources.get);
return xx c;
}
main :: () -> i32 {
r := map((a, b) => a + b, IntCell.{ v = 40 }, IntCell.{ v = 2 });
print("{}\n", r.get()); // 42
0
}