# AILang Roadmap

Priority-ordered list of upcoming work — milestones, features, todos,
and ideas. The orchestrator maintains this file. The user can request
additions; the orchestrator chooses what to remove or reprioritise as
work progresses.

## Conventions

- One checkbox per entry. `- [ ]` is open; `- [~]` is in progress
  (work has started — a plan exists, a branch is open, or commits are
  landing); `- [x]` is done. A finished entry may stay briefly for
  context, then is removed (with a one-line mirror in
  `docs/JOURNAL.md`).
- Each entry is tagged by **kind** and lives under a **priority**
  bucket:
  - **\[milestone\]** — big chunk that will get a `docs/specs/<milestone>.md`.
  - **\[feature\]** — smaller addition inside a milestone, no full
    spec.
  - **\[todo\]** — concrete task that can run without a brainstorm
    (cleanup, doc fix, mechanical refactor, test backfill).
  - **\[idea\]** — not yet decision-ready, no commitment.
- Optional `depends on:` line names another entry that has to land
  first.
- Optional `context:` line points to the JOURNAL entry where the
  rationale lives. The roadmap is intentionally terse; rationale
  stays in JOURNAL.
- Priority buckets:
  - **P0** — in flight. Spec or plan already exists.
  - **P1** — next up. Decision made; not yet started.
  - **P2** — medium-term. Decided in principle, scheduled later.
  - **P3** — ideas. No commitment; may be cut.

## P0 — In flight

- [x] **\[milestone\]** Floats — introduce `Float` as IEEE-754
  binary64 primitive type. One float type only (no `f32`).
  IEEE-conformant equality: `eq : Float → Float → Bool` returns
  `false` for `NaN == NaN`; **no `Eq` instance** (the partiality
  is real and surfaces through `Maybe`-shaped comparators rather
  than through a lying total instance). `Ord` likewise partial:
  `compare : Float → Float → Maybe Ordering`. Includes literal
  syntax in Form-A + Surface, codegen for arithmetic ops,
  conversions Int↔Float, and `Show`-style printing without the
  typeclass machinery (the typeclass wiring lands in Post-22
  Prelude).
  - context: this conversation (2026-05-10) — Float status quo
    was "documented as a primitive but never implemented";
    `crates/ailang-core/src/canonical.rs:14` says "no floats".

## P1 — Next

- [ ] **\[milestone\]** Post-22 Prelude — ship `Show` / `Eq` / `Ord`
  with the three total-orderable primitive instances (Int, Bool, Str);
  rewire `print` through `Show.show`. Float gets `Show` but **not**
  `Eq` / `Ord` (partial — see Floats milestone). Originally queued
  as 22b.4 in the typeclass milestone, kept on hold pending demand.
  - context: JOURNAL 2026-05-09 ("JOURNAL queue"). Floats milestone
    closed 2026-05-10 — partial-Eq/Ord-for-Float story is documented
    in DESIGN.md §"Float semantics", so the Prelude can decide
    what's instanced (Show: yes, Eq/Ord: no for Float).

## P2 — Medium-term

- [ ] **\[feature\]** Operator routing through `Eq` / `Ord` — `==`,
  `<` etc. resolved via the typeclass instead of the built-in
  primitive comparators. No commitment; gated on bench re-baselining
  to make sure the indirection doesn't tank latency.
  - context: JOURNAL 2026-05-09
  - depends on: Post-22 Prelude
- [ ] **\[todo\]** `types` / `ctor_index` overlay shape question —
  decide whether the env's two parallel ctor maps should collapse
  into one overlay, or stay split. Surfaced during the
  env-construction unify audit.
  - context: JOURNAL 2026-05-10 ("Audit close: env-construction unify")
- [ ] **\[feature\]** 22c — typeclass corpus expansion. User-defined
  classes beyond the prelude four; multi-parameter classes; superclass
  chains; richer instance bodies. Deferred from milestone 22.
  - context: JOURNAL 2026-05-09
- [ ] **\[todo\]** Boehm full retirement — remove the transitional
  Boehm GC path now that RC + uniqueness is the canonical memory
  story.
  - context: JOURNAL pre-22, "Boehm transitional"
- [ ] **\[feature\]** Closure-pair slab / pool — codegen tweak to
  pool the env+code closure pairs instead of one-shot heap allocs.
  Bench-gated.
- [ ] **\[todo\]** `FnDef::synthetic` flag — formalise the
  monomorphiser-emitted FnDefs so downstream passes can tell
  user-authored from synthesised at a glance. Currently inferred from
  symbol naming.
- [ ] **\[todo\]** 21'h iteration — final 21' carry-over (latency
  methodology pass). Numbering kept for continuity with the 21' arc.

- [ ] **\[todo\]** `io/print_float` always-emit-`.0` — surface
  printer always emits `.` or `e/E` so re-lex routes to Float;
  the runtime printer (`printf("%g\n", v)`) doesn't, so `2.0`
  prints as `2` (Int-shaped). Asymmetric. Either switch the
  runtime path to a `.0`-fallback printer (matching surface) or
  document the `%g` contract in DESIGN.md §"Float semantics" so
  the LLM-author knows `io/print_float`'s output is for-humans
  not round-trip.
  - context: `docs/specs/2026-05-10-fieldtest-floats.md` finding F1.
- [ ] **\[todo\]** Rustdoc warning sweep — `cargo doc --no-deps`
  reports 16 pre-existing warnings (15 in `ailang-check`, 1 in
  `ailang-core`: private-item links from public doc, unresolved
  intra-crate links). All predate the design-md-consolidation
  milestone; treat as a one-off sweep.
  - context: JOURNAL 2026-05-10 ("Audit close: design-md-consolidation").
- [ ] **\[todo\]** Architect-iron-law standing-grep extension —
  the architect agent's drift review should run the four sweep
  invariant greps on every milestone-close so DESIGN.md cannot
  silently regrow history anchors / REVERTED narratives /
  workflow detail / stale cross-references. Path-anchored
  exceptions (`docs/specs/2026-05-09-*`) need an allowlist.
  Same extension should add the **lockstep-checklist** the
  Floats fieldtest exposed: for every new typecheck reject arm
  on a pattern shape, verify the corresponding desugar pass does
  not eat that shape first; for every new lowering arm in
  `lower_app`, verify `is_static_callee` recognises it. Both
  shipped silently-broken in the Floats milestone (B1 and the
  iter-4.2/4.4 pull-forwards) and the architect missed them.
  - context: JOURNAL 2026-05-10 ("Milestone close:
    design-md-consolidation"); 2026-05-10 ("Fieldtest close:
    Floats milestone") — B1 + architect-checklist follow-up.
- [ ] **\[todo\]** `design_schema_drift.rs` fidelity widening —
  current test checks anchor *presence* anywhere in DESIGN.md;
  the audit found that `[high]` schema gaps in §"Data model"
  are invisible because anchors live in Decision 11 instead.
  Constrain the test to scan only §"Data model" + ParamMode
  block, or extract JSON-schema blocks into a machine-readable
  file the test consumes.
  - context: JOURNAL 2026-05-10 ("Audit close").

## P3 — Ideas

- [ ] **\[idea\]** Latency methodology rework — switch from per-run
  timing to a histogram-based approach so tail-latency regressions
  are visible without re-running. Queued from 21'g.
- [ ] **\[idea\]** Parser-test backfill for 22b.4a-era duplicate-clause
  sites (class × 3, class method × 2, instance × 3, instance method
  × 1). No regression pin today; only worth it if a 22b.4a-era
  diagnostic needs to change.
  - context: JOURNAL 2026-05-10 ("Iteration 22-tidy.7")
- [ ] **\[idea\]** `write_type` `Type::Forall` arm in
  `crates/ailang-prose/src/lib.rs` silently drops constraints in
  inline-type rendering. Dormant — surface forms today only carry
  forall at fn-signature top level. Fix only if a future feature
  carries forall + constraints inline.
  - context: JOURNAL 2026-05-10 ("Iteration 22-tidy.6")
- [ ] **\[idea\]** Richer integration paths between RC and
  uniqueness — deferred from the 21' arc; revisit once the
  uniqueness inference covers more program shapes.