docs(reify): name Phase 4 self-reference pair declare()/define()

User picked the declaration-vs-definition split over reserve/complete.
declare() returns a forward nominal Type handle (named from the :: LHS);
define(handle, info) fills its body. reify(info) stays the one-shot
sugar. Updated PLAN-REIFY Phase 4 + Contract 5 + CHECKPOINT-REIFY.

current/CHECKPOINT-REIFY.md

@@ -61,16 +61,17 @@ only at the `E :: reify(...)` const-decl site (`decl.zig`) and reads a LITERAL
 (and likely generalize the literal-AST reader, or evaluate via the interpreter, for
 non-literal `TypeInfo`).
 
-SELF-REFERENCE = Phase 4, API DECIDED (user-directed): explicit **`reserve()` →
+SELF-REFERENCE = Phase 4, API DECIDED (user-directed): explicit **`declare()` →
-`complete()`** (NOT a `reify_rec((self)=>…)` closure). `reserve()` returns a forward
+`define(h, info)`** (the declaration-vs-definition split; NOT a `reify_rec((self)=>…)`
-nominal `Type` handle (named from the `::` LHS) usable freely in any later `TypeInfo`
+closure). `declare()` returns a forward nominal `Type` handle (named from the `::`
-— `*List`, `[]List`, and across types for MUTUAL recursion the one-`self` closure
+LHS) usable freely in any later `TypeInfo` — `*List`, `[]List`, and across types for
-couldn't express; `complete(handle, info)` fills the body. `reify(info)` stays as the
+MUTUAL recursion the one-`self` closure couldn't express; `define(handle, info)` fills
-one-shot sugar. Maps onto existing machinery: reserve = empty nominal slot
+the body. `reify(info)` stays as the one-shot sugar. Maps onto existing machinery:
-(`reserveShadowEnumSlot`-style), complete = `buildEnumInfo` + `updatePreservingKey`,
+declare = empty nominal slot (`reserveShadowEnumSlot`-style), define = `buildEnumInfo`
-struct-stub→tagged_union re-key already handled (`internNamedTypeDecl`'s
++ `updatePreservingKey`, struct-stub→tagged_union re-key already handled
-`adoptsForwardStructStub`). Loud invariants: never-completed reserve = hard error;
+(`internNamedTypeDecl`'s `adoptsForwardStructStub`). Loud invariants: never-defined
-by-value self-inclusion rejected (infinite size). Full write-up in PLAN-REIFY Phase 4.
+declare = hard error; by-value self-inclusion rejected (infinite size). Full write-up
+in PLAN-REIFY Phase 4.
 
 ## Known issues
 None yet.

current/PLAN-REIFY.md

@@ -25,9 +25,9 @@ tagged-union, and **replaces** a would-be `enum($T)` generic-enum language featu
 3. **Validate loudly** at the `intern`/`internNominal` choke point (`types.zig:411-439`).
 4. **Comptime-only, JIT-free** — a type-table op in the interpreter; no S1 dependency.
 5. **Reference-based self-reference** (`*Self`/`[]Self`) via an explicit
-   **`reserve()` → `complete()`** pair (reserve-placeholder→complete reuse of
+   **`declare()` → `define()`** pair (reserve-placeholder→complete reuse of
    `nominal.zig:86/108/120`, `types.zig:442`); **by-value recursion rejected**. (See
-   Phase 4 — the `reserve`/`complete` API supersedes the earlier `reify_rec` closure.)
+   Phase 4 — the `declare`/`define` API supersedes the earlier `reify_rec` closure.)
 
 Surface follows the **`#builtin`** pattern of the existing reflection builtins
 (`type_of`/`field_count`/`field_name` in `library/modules/std/core.sx`,
@@ -81,28 +81,29 @@ Examples: `06xx` (comptime, deterministic), `11xx` (diagnostics for loud failure
 |---|---|---|---|
 | 3.0 | lock | `make_enum(variants) -> Type` (sx lib over `reify`); `RecvResult($T)`/`TryResult($T)` as type-fns. Behavior-lock: `RecvResult(i64)` constructs + matches. | `library/modules/std/*` |
 
-### Phase 4 — reference-based self-reference (explicit reserve → complete)
+### Phase 4 — reference-based self-reference (explicit declare → define)
-> **API decision (user-directed):** an explicit **`reserve()` / `complete()`** pair,
+> **API decision (user-directed):** an explicit **`declare()` / `define(h, info)`**
-> NOT a `reify_rec((self) => …)` closure. `reserve()` returns a forward-declared
+> pair (the canonical declaration-vs-definition split), NOT a `reify_rec((self) => …)`
-> nominal `Type` HANDLE — a real `Type` value usable freely in any later `TypeInfo`
+> closure. `declare()` returns a forward-declared nominal `Type` HANDLE — a real
-> (`*List`, `[]List`, and across types for MUTUAL recursion, which the one-`self`
+> `Type` value usable freely in any later `TypeInfo` (`*List`, `[]List`, and across
-> closure can't express). `complete(handle, info)` fills the body. `reify(info)` stays
+> types for MUTUAL recursion, which a one-`self` closure can't express).
-> as the one-shot sugar (= reserve + complete + return) for the non-recursive case.
+> `define(handle, info)` fills the body. `reify(info)` stays as the one-shot sugar
-> No special self-ref node in `TypeInfo` — a reserved type is just a `Type`.
+> (= declare + define + return) for the non-recursive case. No special self-ref node
+> in `TypeInfo` — a declared type is just a `Type`.
 > ```sx
-> List :: reserve();                                  // name from the `::` LHS
+> List :: declare();                                  // name from the `::` LHS
-> complete(List, .enum(.{ variants = .[
+> define(List, .enum(.{ variants = .[
 >     EnumVariant.{ name = "cons", payload = *List },  // reference it freely
 >     EnumVariant.{ name = "nil",  payload = void } ] }));
 > ```
-> Loud invariants: (a) a `reserve()` never `complete()`d = hard error at end of
+> Loud invariants: (a) a `declare()` never `define()`d = hard error at end of
 > comptime (no silent empty type); (b) by-VALUE self-inclusion (`payload = List`, not
 > `*List`) rejected — infinite size, same check recursive source types get.
 
 | Step | Commit | What | Files |
 |---|---|---|---|
-| 4.0 | xfail | `reserve()` returns a forward nominal `Type`; `complete()` fills it. Recursive enum via `*Self` (tree/list). Red. | `examples/06xx-*` |
+| 4.0 | xfail | `declare()` returns a forward nominal `Type`; `define()` fills it. Recursive enum via `*Self` (tree/list). Red. | `examples/06xx-*` |
-| 4.1 | green | `reserve` = intern empty nominal slot (`reserveShadowEnumSlot`-style); `complete` = `buildEnumInfo` + `updatePreservingKey`; struct-stub→tagged_union re-key already handled by `internNamedTypeDecl` (`adoptsForwardStructStub`). | `src/ir/lower/nominal.zig`, `src/ir/lower/decl.zig`, `src/ir/types.zig` |
+| 4.1 | green | `declare` = intern empty nominal slot (`reserveShadowEnumSlot`-style); `define` = `buildEnumInfo` + `updatePreservingKey`; struct-stub→tagged_union re-key already handled by `internNamedTypeDecl` (`adoptsForwardStructStub`). | `src/ir/lower/nominal.zig`, `src/ir/lower/decl.zig`, `src/ir/types.zig` |
 
 ### Phase 5 — validation + loud diagnostics
 | Step | Commit | What | Files |