Brummel
657b24bfc9
A design discussion on 0008 surfaced four refinements; this records them in the exploratory model. Still design exploration, not a spec commitment. - §3.4 (new): the keywords are adjectival, not verbal. `own`/`borrow` are acquisition verbs — native on a parameter (the callee acquires), backwards on a return (the callee disposes; §3.1's own text switches feet between the two readings). Naming the mode adjectivally (`owned`/`borrowed`) describes the value the receiver holds and is position-independent, strengthening §3's uniformity rather than breaking it. Carries a safety stake, not only readability: a wrong `own` is the double-free (§6), and the verb form is a mis-annotation pump pointed that way. Notes the corroborating `ret_mode: ParamMode` type-name smell (a return mode is a covariant promise, not a contravariant param demand). - §4.4: "fixed modes suffice" is contingent on the point-free cut, not a standalone theorem. Adds the structural discriminator — today's HOFs control both ends of their seam, so the seam mode is determinate; only the wire-two-black-boxes kind (point-free) needs a mode variable. - §5.1–5.3 (new): a tuple question exposed that `ret_mode` is flat but ownership is a tree over the type — a single top-level `Own` on a mixed Pair (owned field + borrowed field) decs borrowed data on drop. Resolved to regime A (borrows may not escape into an escaping heap structure → transitive ownership → flat `ret_mode` sound), not a per-field mode tree (regime B = lifetimes). For compound returns, verification is constitutive of the flat representation's meaning, not a separable phase — sharpening Q2 to "must" there. Multi-return is the ownership-honest return path (flat per-position modes, no reachability pass) but does not subsume the typed boxed aggregate; the boxing point is the ownership commit. - §7: Q2 sharpened (compound returns force it), Q3 rewritten (adjectival keywords + the pre-cutover timing, since a post-cutover rename is a second irreversible hash reset), Q4 added (multi-return adoption); resolved-footer extended with regime A and multi-return≠tuple. - §8 (new): relation to Rust. Concedes the primitive-level convergence (own/borrow ≈ move/borrow, regime A ≈ Rust's escape rule, unboxed product ≈ tuple, RC ≈ Rc/Arc), then names what AILang drops and why: no lifetime polymorphism (the point-free cut removes the pressure that makes Rust carry it), no `&mut`/shared-XOR-mutable (no shared mutable refs; mutation rides uniqueness, the Clean lineage), no elision (§2's no-defaults is the opposite of Rust's elision). Scoped to the totality-relevant divergences; the broader memory-model lineage is cross-referenced to 0004 rather than duplicated.