Commit Graph

12 Commits

Author SHA1 Message Date
Brummel 82635fa259 refactor: Cell becomes the hot-path value carrier (C7/C8 realization)
Motivation
----------
The C7 realization note (cd3d1ca / 049f22a) deferred this step: with
Scalar split into { kind, cell }, the tag-free Cell could become the
hot-path carrier, but eval and the edges still flowed the fatter
self-describing Scalar. This lands the swap.

Change
------
- Node::eval now returns Option<&[Cell]>; every node out-buffer is
  [Cell; N]. The inter-node forward copies the row into a Vec<Cell> and
  pushes each field via a new branch-free, infallible AnyColumn::push_cell
  — the edge from_field->slot kind match is verified once at bootstrap
  (C7), so the runtime push needs no per-value kind check. It only removes
  a Result the forward path already .expect()ed.
- Scalar stays on the self-describing dynamic boundaries: the param plane
  (build / bind / compile_with_params / sweep points / RunManifest),
  AnyColumn::get (the type-erased read for sinks / serde), and source
  ingestion (Source::next, the heterogeneous C3 merge). The fallible
  AnyColumn::push is retained for ingestion + the kind-guard tests.

Trade
-----
The per-value runtime kind check on node OUTPUT is removed: a node that
builds a wrong-kind cell pushes raw bits with no panic. This is the same
authoring-bug class C8 already leaves to a debug_assert (output width);
node-output-kind correctness is the node's declared FieldSpec contract,
caught by each node's own eval test. Cross-node kind agreement still rests
on the bootstrap kind-check (bootstrap_rejects_*_kind_mismatch, green).

Tests
-----
Behaviour-preserving (C1): 285 green, 0 red. The only test-expectation
edits are carrier re-spellings (Scalar::f64(x) -> Cell::from_f64(x)) of
identical values; test column writes and out-of-graph channel rows stay
Scalar (the spec's three-role rule). Adds an AnyColumn::push_cell
round-trip test plus a cross-kind end-to-end forward test (a mixed
f64/i64 record whose bit patterns diverge across kinds — pins the i64
forward path the f64-only tests cannot catch). Ledger C7/C8 notes updated.

Gates: cargo build / test / clippy --all-targets -D warnings / doc
--workspace all clean.

closes #74
2026-06-16 13:17:49 +02:00
Brummel cd3d1ca9ed refactor(aura-core): split Scalar into a tag-free Cell + ScalarKind
Motivation
----------
`Scalar` was a tagged enum (I64/F64/Bool/Ts), so every scalar value
physically carried its own kind tag. But the kind is already known from
the schema/port/column the value flows through (C7: the type is a
property of the column, not of the value — the hot path is already
columnar `Column<T>`, and `AnyColumn::get` *reconstructs* the tag from
the column on the way out). The per-value tag was therefore redundant
with the kind the surrounding context already holds.

That redundancy had three costs:

  * It baked an implicit `match` (a branch) into every function that read
    a Scalar payload — even where the caller statically knew the type.
    The tag could never be exploited away.
  * Size: a tagged enum is tag + payload = 16 bytes (f64/i64 alignment),
    twice the 8 bytes the value needs. A `Column<Scalar>` would be double
    the memory and half the cache utilisation.
  * It is the shared root of several downstream papercuts we keep hitting
    — the lossy f64 manifest field, the `unreachable!` panic on a
    non-numeric param, the serde-tag question — all symptoms of "the type
    is baked into the value".

Change
------
Introduce `Cell`: a type-erased 64-bit word (`struct Cell(u64)`) that is
not readable without external type context. It is constructed per base
type (`from_i64/from_f64/from_bool/from_ts`) and read only by naming the
type at the call site (`i64()/f64()/bool()/ts()`) — each a branch-free
bit-cast. The hot path resolves the kind once at the boundary (from the
schema) and then reads natively, with no per-value branch. `Cell` knows
nothing of `Scalar` or `ScalarKind`; the dependency is strictly one-way,
and it lives in its own `cell.rs` (more is planned on top of it).

`Scalar` becomes `struct { kind: ScalarKind, cell: Cell }` — the
self-describing form for the dynamic boundaries (builder binding,
serialization, rendering), built on top of `Cell`. Its `as_*` accessors
now `debug_assert` the kind and return the native value (free in
release); calling the wrong accessor is a caller bug, not a checked
`Option`. The variant constructors `Scalar::I64(..)` become associated
fns `Scalar::i64(..)`.

`PartialEq` is hand-written (not derived) to preserve the former enum's
value semantics: kinds must match, then native payloads compare, so f64
keeps IEEE-754 behaviour (`NaN != NaN`, `+0.0 == -0.0`) and a kind
mismatch is never equal even when the raw words coincide. A fixture
(`scalar_eq_is_value_not_bitwise`) pins exactly the cases where bit- and
value-equality diverge, so it can't silently regress. `Cell`'s own
`Eq`/`Hash` stay bitwise — correct for a raw word.

The change is behaviour-preserving: Scalar's observable behaviour is
identical to the pre-Cell enum (the value-equality fixture proves it);
only the internal representation changed. The ~440 call sites across the
workspace are a mechanical constructor rename plus ~12 destructuring
sites (match-arms / `let`-patterns) rewritten to `kind()` + `as_*`.

Verified: cargo build --workspace --all-targets, cargo clippy --workspace
--all-targets -- -D warnings, cargo test --workspace — all green.
2026-06-16 12:12:52 +02:00
Brummel a8bd52eaff refactor(aura-core): own FieldSpec.name to drop the derive_signature heap leak
FieldSpec.name was &'static str, forcing derive_signature to Box::leak
every re-exported composite OutField name. Because compile_with_params
reruns derive_signature per sweep point, an N-point sweep over an
M-output-field composite leaked N×M boundary names unbounded — a scaling
wall the moment the World/sweep layer compiles families per point.

Pull FieldSpec.name to String, mirroring the already-owned PortSpec.name
and ParamSpec.name: a composite re-exports interior fields under runtime
boundary names, so ownership is the correct model, not a workaround.
FieldSpec loses Copy; the only fallout is one borrow at the render site.
leak_name/Box::leak deleted.

Behaviour-preserving: signature contents unchanged, all 231 tests green.
2026-06-14 22:21:15 +02:00
Brummel e304dbaae1 feat(aura-core): name input ports
PortSpec gains a non-load-bearing `name: String`, so an input port is named just
as FieldSpec.name (output) and ParamSpec.name (param) already are — input ports
were the lone unnamed member of the node signature. Identity stays positional by
slot (C23); the name is render/debug only, never read by bootstrap or the run
loop. PortSpec drops Copy (String is not Copy), exactly as ParamSpec already does.

- Every aura-std node names its input slots: SMA/EMA "series", Sub/Add "lhs"/"rhs",
  Exposure "signal", SimBroker "exposure"/"price" (the slots become
  self-documenting), LinComb "term[i]" and Recorder "col[i]" generated in their
  build loops (mirroring LinComb's existing weights[i] param loop).
- derive_signature carries a composite's Role.name into the derived input port
  (it was dropped before — the output side already carried FieldSpec.name), so the
  graph model is homogeneously named at both levels.
- model_to_json (port_json + the composite-header inputs in scope_json) emits the
  name as a third tuple element: ["f64","any","exposure"]. The byte golden was
  re-captured (machine bytes) and its substring twins updated; the model is now
  fully named across inputs/outputs/params.
- All 16 PortSpec construction sites threaded in one compile-gate change; test
  fixtures carry fixture names. C8 realization note added to the design ledger.

Why name-only, no validation: the name is a pure debug symbol. Wire-by-name was
rejected (it would be a C23 contract change). Bootstrap slot-wiring validation
(which would close #21's same-kind swap footgun) is deferred to its own cycle —
a name alone does not catch the swap; it makes the slots self-documenting and
gives a future validation something to check against.

Verified: cargo test --workspace 168 green; clippy --all-targets -D warnings
clean; cargo build --workspace clean. Read-only render path (C9), no serde (C14),
scalar kinds unchanged (C4).

closes #50
refs #21
refs #51
2026-06-10 16:19:08 +02:00
Brummel 1b3909316e feat(aura): node signature lives in the blueprint; collapse Blueprint into Composite
Consolidate the node data structure so every node's signature (NodeSchema:
inputs/output/params) is declared once and exists in the blueprint pre-build,
and dissolve the special "root graph" type. Behaviour-preserving (C1).

Signature vs sizing
- NodeSchema is now the static signature only: InputSpec -> PortSpec{kind,firing},
  with lookback removed. The signature is fully static per blueprint (input
  kinds/firing, output fields, params); LinComb's variable arity is a builder arg,
  not an injected param.
- The one param-dependent quantity, an input's buffer lookback (e.g. Sma's window =
  its injected length), moves out of the signature to Node::lookbacks() -> Vec<usize>,
  read only by bootstrap for sizing. Node::schema() is removed.
- LeafFactory -> PrimitiveBuilder, which carries the full NodeSchema. The built node
  no longer re-declares it: closes the params-declared-twice drift (#36, the 8
  per-node factory_params_match_built_node_schema lockstep tests are deleted — their
  subject is now structurally impossible) and a value-empty recipe exposes its full
  I/O interface pre-build (#43).

Root is just a bound composite
- struct Blueprint is deleted; its compile/bootstrap/param_space methods move onto
  Composite. Role gains source: Option<ScalarKind> (None = open interior port,
  Some = bound ingestion feed). A composite is runnable iff every root role is bound;
  the "main graph" is no longer a category, only the fully-source-bound composite.
  New error CompileError::UnboundRootRole for an open root role.
- BlueprintNode::signature() answers uniformly for both arms: Primitive returns the
  builder's declared schema, Composite derives it from the interior (role kinds in,
  OutField kinds out, aggregated params), pre-build, no build.

compile -> FlatGraph -> bootstrap
- compile validates structure pre-build via signature() (validate_wiring: range +
  kind, returning the same variants as before, so an edge kind fault is now caught
  before any build closure fires) and emits FlatGraph{nodes,signatures,sources,edges}.
- bootstrap consumes the FlatGraph: kinds/firing/output from the carried signatures,
  buffer depth from node.lookbacks(). SourceSpec survives as the flat descriptor.

Renames: BlueprintNode::Leaf -> Primitive, LeafFactory -> PrimitiveBuilder.

Render (aura-cli/src/graph.rs) is migrated compile-only: it takes &Composite, maps
bound roles to the same source-entry shape, so both render goldens reproduce
byte-identical output (no re-capture needed). Render-fidelity tuning is the next cycle.

Verification (orchestrator-run, not agent-reported): cargo build --workspace green;
cargo test --workspace 150 passed / 0 failed; cargo clippy --workspace --all-targets
-D warnings clean. All pinned determinism/run-output tests pass with values unchanged;
no behavioural assertion was altered to go green. 5 new tests assert the signature is
pre-build and uniform, that compile rejects a kind mismatch without building (via a
panicking builder), UnboundRootRole, and lookbacks()/signature arity agreement.

Deferred to cycle-close audit (per plan): docs/design/INDEX.md and some aura-std
module docs still name the old Node::schema()/LeafFactory/BlueprintNode::Leaf/
Blueprint::param_space contracts; prose reconciliation is the architect's at audit.

closes #43 #36
2026-06-09 12:49:22 +02:00
Brummel 4b64409036 feat(aura-core,aura-std,aura-engine,aura-cli): inject a param-set vector at bootstrap (#31)
Cycle B of milestone "The World — parameter-space & sweep". A blueprint is now
value-empty: a leaf holds a param-generic recipe, not a built node, and a positional
Scalar vector is bound slot-by-slot at bootstrap — so one blueprint bootstraps into
many distinct instances under different vectors, with no cdylib rebuild (C12/C19).
This is the binding primitive a sweep (#32) drives.

Ratified design (brainstorm): value-empty reconstruct-through-new() over
mutate-in-place and over a default-bearing variant. The value lives only in the
injected vector (no baked default), keeping the blueprint a pure param-generic
recipe (C19); every injected value flows through the node's own constructor (the
single sizing/validation gate).

- aura-core: LeafFactory { name, params, build } — the recipe (params -> sized node
  through `new`); Scalar::as_i64/as_f64 value accessors. Node trait unchanged.
- aura-std: each of the 7 nodes exposes factory() (SMA length:I64, Exposure
  scale:F64, LinComb arity x weights[i]:F64; Sub/Add/SimBroker/Recorder paramless,
  capturing their non-param construction args — pip_size, the Recorder channel).
- aura-engine: BlueprintNode::Leaf(LeafFactory), From<LeafFactory>; param_space()
  reads factory.params() pre-build; compile_with_params/bootstrap_with_params build
  each leaf from its kind-checked slice while lowering (build-then-wire), arity
  checked up front via param_space().len(); CompileError::{ParamKindMismatch,
  ParamArity}. compile/inline/edge-rewrite are structurally unchanged, so the
  compilat stays bit-identical for a given point (the bit-identity and both
  param_space mirror tests stay green). The vestigial pre-build Composite::schema /
  BlueprintNode::schema (no live caller — interface resolution is structural on the
  built flat nodes) are removed.
- aura-cli: the blueprint view labels leaves by bare type via LeafFactory::label()
  (`[SMA]`) — the ascii-dag renderer cannot render wide cluster-sibling labels (see
  spec); the compiled view still labels valued (`SMA(2)`). The sample supplies its
  point as a vector; the mis-wiring swap moved to the compiled view.

The #34 dual-traversal drift hazard is subsumed: compile_with_params consumes the
vector in the same recipe walk param_space() reports, so the two share one
traversal.

Verified: cargo build/test --workspace green (127 tests, incl. bit-identity, both
mirror tests, and 4 new injection tests — different-vector-different-run, kind
mismatch, arity, determinism); clippy --workspace --all-targets -D warnings clean;
`aura graph` blueprint view renders cleanly.

Scope: one vector -> one instance. Deferred: sweep enumeration (#32), domain
validation (#32/C20), single-run authoring convenience (#35).

closes #31
2026-06-07 21:04:52 +02:00
Brummel 931109df58 feat(aura-core,aura-std,aura-engine): declare node tunable params (#30)
Cycle A of milestone 'The World — parameter-space & sweep'. A node now declares
its tunable parameters in its C8 schema, and a blueprint aggregates them into one
flat, inspectable param-space — the root that unlocks the C12 orchestration axes
(#31 bind, #32 sweep), filling the gap C8/C23 name 'deliberately not in the schema
yet'.

- aura-core: ParamSpec { name: String, kind: ScalarKind } as a third schema-
  declaration type; NodeSchema gains a third field 'params'. name is String (not
  &'static like FieldSpec) because a vector knob carries a runtime index and
  aggregation prefixes the composite path.
- aura-std: Sma declares [length:I64], Exposure [scale:F64], LinComb expands to N
  flat [weights[i]:F64] (N = its input arity, topology-fixed per C19); Sub/Add/
  SimBroker/Recorder declare none (pip_size is metadata, C10/C15; Recorder is
  wiring).
- aura-engine: Blueprint::param_space() walks the graph-as-data depth-first in
  lower_items order, path-qualifying via the already-public Composite::name() — a
  read-only projection (C9). compile/inline_composite/lower_items are untouched, so
  the compilat stays bit-identical (composite_sma_cross_runs_bit_identical_to_hand_wired
  and the golden render tests stay green).

Design: param identity is positional (slot after the deterministic inline order,
C23 'by index not name'); the path-qualified name is a non-load-bearing debug
symbol — same-type siblings in one composite share a name, uniqueness is at the
slot. Flat over a structured arity-bearing ParamSpec because flattening is
unavoidable (a sweep enumerates a flat point-space) and structure-in-the-runtime
is the nested-composite reading C23 rejects (see spec 0015 for the full rationale).

Scope is declaration + aggregation + inspection only; binding (#31), sweep
enumeration (#32), search-range, validity-constraint, and default-range/slider are
deferred. An E2E test pins the load-bearing C23/#31 invariant: param_space() slot
order mirrors compile()'s flat-node param order, kind-by-slot, on the SMA-cross
harness. fieldtests/ (excluded crates) left as frozen snapshots.

Verified: cargo build/test --workspace green (64 tests), clippy --all-targets -D
warnings clean; compile/inline diff empty.

closes #30
2026-06-07 15:29:58 +02:00
Brummel 0a855c3943 feat(aura-cli): aura graph renders a wired graph as an ASCII DAG (#13)
Make a wired graph introspectable so a mis-wiring becomes visible. Two
selectable views, both authored from one built-in sample blueprint:

  aura graph             clustered blueprint view — composites drawn as named
                         ascii-dag cluster boxes (pre-inline, C9)
  aura graph --compiled  flat compilat view — composite boundaries dissolved
                         (C23); the graph the run loop actually runs

The payoff is intrinsic, param-carrying node labels: two SMAs read SMA(2) /
SMA(4), so a swapped fast/slow input reads back differently. This is realized
by a `label()` default method on the core Node trait — a non-load-bearing
render symbol the run loop never reads (wiring is by index), the symbol C23
already reserves citing #13. Recorded as a C8 refinement in the ledger.
Rejected the alternatives in brainstorm: a separate Describe trait (forces a
combined trait-object dance for a label the ledger calls non-load-bearing) and
extrinsic parallel labels (decoupled from the node, so an author can label the
slow SMA "fast" and mask the very bug the render exists to surface).

Mechanism:
- aura-core: Node::label() default method (additive, object-safe, single-line).
- aura-std: per-node overrides — SMA(n)/Exposure(s)/SimBroker(p) carry params;
  Sub/Add/LinComb/Recorder are bare (their identity is not a mis-wiring axis).
- aura-engine: Composite gains an authored `name` (cluster title; dissolves at
  inline) + read-only graph-as-data accessors on Blueprint/Composite. No
  external dependency — the engine stays dependency-pure (C16); ascii-dag lives
  only in aura-cli. The label-free index-wired compilat (C23) is unchanged.
- aura-cli: ascii-dag v0.9.1 + a graph.rs adapter (Vertical mode; labels
  materialized into an owned Vec<String> that outlives the borrow-based Graph).
  `aura run` is untouched (the sample duplication is dedup idea #14).

Tests: a concern-defining test (swapped sample renders != correct), structure
pins (cluster present in blueprint view, absent in compiled view), per-node
label disambiguation, and two frozen byte-goldens of the deterministic render.
The cycle-0012 bit-identical and run-sample non-regression tests stay green.

Verified by the orchestrator (not the agent report): cargo build --workspace
clean; cargo test --workspace all green; cargo clippy --workspace --all-targets
-D warnings clean; both views run live and render as expected.

closes #13
2026-06-05 20:56:52 +02:00
Brummel 1100a60c76 feat: recording is a node role, not a type (multi-sink substrate)
Replace the engine's single observe: usize recording affordance with
recording-by-node, so one run records many streams. A recording node
reads its typed input windows + ctx.now() in eval and pushes the record
to a destination it holds as a field (a channel, a chart handle) — an
out-of-graph side effect. There is no Sink type, trait, or engine flag:
a pure-consumer node returns None, and a node may record AND return a
forwarded output in the same eval (the C8 "both" case). In-graph routing
stays engine-owned data (the edge table); the escape out of the graph is
the node's own side effect, and that boundary is the determinism /
graph-as-data boundary.

Engine surface shrinks: Ctx gains now: Timestamp + now() (C2-causal, the
present cycle's timestamp); Harness loses the observe field, its
observe >= n bootstrap check, and the per-cycle observed-row collection;
bootstrap drops its 4th param; run returns (). Recorded streams are now
sparse and timestamped (a record per fired cycle) instead of the dense
Vec<Option<row>>.

The Ctx::new signature change touched 9 call sites across three crates
(not the 3 the spec estimated) — aura-std's node tests and the engine
run loop were threaded too. The engine test suite migrated to a
test-local Recorder fixture whose read-back is an mpsc channel, never
Rc/RefCell, keeping aura-engine/src purity-clean (C7). Eight new proof
tests cover the multi-sink headline, producer-and-sink, mixed-kind
recording, all-fields tap, both recorder firing modes, determinism, and
recorder-edge kind rejection. C8/C22 gain cycle-0006 realization notes.

Gates: workspace test 45 green (core 20, std 3, engine 22), clippy
-D warnings clean, purity grep clean (only a comment names Rc/RefCell).

closes #2
2026-06-04 14:38:26 +02:00
Brummel 5228542bfd feat: node output is a record (composite stream), not a single scalar
Cycle 0005 (BLOCKER #1): a node's output generalizes from one scalar to a record
of K >= 1 named base-scalar columns, with a scalar being the degenerate K = 1
case. A node keeps exactly one output port; its payload is now an ordered bundle
of base columns (a composite stream, C7). This unblocks every multi-column
producer the engine needs next -- OHLCV bars and, later, the C10 position-event
table -- none of which could exist while a node emitted at most one column.
Revises C8, sharpens C7 in the design ledger.

Contract (aura-core):
- `NodeSchema.output: ScalarKind` -> `Vec<FieldSpec>` (FieldSpec = { name:
  &'static str, kind }; the field position is what an Edge binds, the name is
  metadata for later sinks/playground, C18).
- `Node::eval -> Option<Scalar>` -> `-> Option<&[Scalar]>`: a node fills a buffer
  it owns (sized once at construction) and returns a borrowed K-field row; `None`
  still means filter/not-warmed. This is the C7-faithful representation chosen
  with the user: zero per-cycle heap allocation on the forward path (rejected:
  Option<Vec<Scalar>> allocates per fire; an inline fixed [Scalar; N] bakes a
  width cap; engine-owned output columns invert the eval model). Scalar output is
  the degenerate 1-field record -- no separate scalar path.

Field-wise binding (aura-engine):
- `Edge` gains `from_field: usize` -- which producer column this edge forwards.
  Consuming a whole record is N edges; there is no "bind whole record" mechanism.
- bootstrap kind-checks per field (`from.output.get(from_field)` -> BadIndex if
  out of range; `field.kind != slot.kind` -> KindMismatch).
- the run loop copies a producer's returned row into one reused scratch buffer
  (resolving the borrow; no per-cycle alloc once warm) and scatters
  scratch[from_field] into each out-edge slot. `NodeBox.out_len` (set at
  bootstrap) backs a debug_assert on the returned row width. `run` returns
  `Vec<Option<Vec<Scalar>>>` (the observed node's full row per cycle -- a
  materialization-surface alloc, not the inter-node hot path).
- the K fields of one record are co-fresh by construction (one eval, one
  timestamp), so C6 is untouched.

aura-std: Sma/Sub migrate to the 1-field degenerate case (hold a [Scalar; 1]
buffer; behaviour unchanged). Sub drops #[derive(Default)] (Scalar has no Default)
for a manual Default.

Proof (aura-engine tests, +5): an Ohlcv 5-field bundler fed by five
timestamp-aligned barrier sources emits one complete bar per timestamp
(ohlcv_bundles_five_field_record); a downstream Sub binds high(1)-low(2)
field-wise, observed end-to-end + a determinism re-run
(edge_binds_single_field_high_minus_low); a second consumer binds close(3)-open(0)
on the same record (distinct_edges_read_distinct_fields); must-fail:
bootstrap_rejects_from_field_out_of_range (BadIndex),
bootstrap_rejects_per_field_kind_mismatch (a TwoField [f64,i64] producer, the i64
field into an f64 slot). All prior 0003/0004 tests adapted to from_field + the Vec
return, expected vectors unchanged (scalar = 1-field record).

Gates re-run by the orchestrator (not just the agent): cargo build/test
--workspace --all-targets (36: aura-core 19 + aura-std 3 + aura-engine 14, 0
failed) / clippy --workspace --all-targets -D warnings clean; surface-purity grep
(no dyn-Any / Rc / RefCell) clean. Ledger C8/C7 edits verified
(Option<&[Scalar]> present, "one series per node" gone, cycle-0005 realization
note added). The glossary composite/node record-reality pass is the audit-time
follow-up.

closes #1
refs walking-skeleton

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-03 15:55:20 +02:00
Brummel f37b2a35d3 feat(engine): firing policies A/B + the k-way ingestion merge
Cycle 0004: the reactive-semantics layer. The engine now merges multiple
timestamped sources into one chronological cycle stream (C3) and gates each
node's re-evaluation by a per-input firing policy (C5/C6) — both rails shipping
together, as the user required ("must sit right from the start").

- `Firing` (aura-core) — a per-input enum on `InputSpec`, where C8 places firing:
  `Any` (mode A, fire-on-any-fresh + hold / as-of join) and `Barrier(u8)` (mode B,
  all-fresh barrier / synchronizing join). Default-free; Sma/Sub declare
  `Firing::Any`, so under a single source ticking every cycle their behavior is
  unchanged (backward compatible — the 0003 fan-out/join DAG still emits
  [None,None,None,2,2,2]).
- `SourceSpec` + the k-way merge (aura-engine) — `run` takes one
  `(Timestamp, Scalar)` stream per source and merges them by (timestamp, source
  index) (C4 ties by declaration order). One record = one cycle. This is the
  permanent ingestion core; the Source trait + data-server IO (C3/C11) are a
  later orthogonal cycle (the user scoped this cycle to the reactive semantics).
- Two read clocks, both load-bearing (resolves the 0003 audit's "0004 owns
  cycle_id" with no write-only field): each push stamps the input slot with
  `fresh_at` (the cycle_id — freshness epoch, C5: fresh iff fresh_at == cycle_id)
  and `last_ts` (the data timestamp — barrier token, C6: a barrier group is
  complete iff all members carry last_ts == T). The `fires()` predicate ORs the
  groups; the ">=1 member fresh this cycle" clause is the once-per-timestamp
  guard. Sample-and-hold falls out of the push model: a non-firing node pushes
  nothing, so consumers keep seeing the held value via window[0].

Key design call, studied against RustAst (src/ast/rtl/streams/): the barrier
token is the data *timestamp*, not cycle_id. RustAst's
last_cycle_per_input.all(== cycle_id) synchronizes one source's fan-out but
cannot synchronize independent sources — under C4 four same-timestamp sources
are four different cycle_ids, so the cycle_id barrier never fires for C6's own
OHLC example. Substituting timestamp is the minimal faithful generalization
(fires both the diamond rejoin and the multi-source bar). Mode A and the k-way
merge are both new (RustAst had neither); RustAst's total_count push counter is
aura's already-built Column::run_count.

Both rails proven on identical sources, firing-only difference:
- mode A (AsOfSum): [None,None,120,130,140,240] — holds the slow input;
- mode B (BarrierSum): [None,None,120,None,None,240] — waits for timestamp
  coincidence;
- mixed A+B (MixedSum): the OR-combine fires both when the barrier pair completes
  (holding the as-of input) and when the as-of input ticks (holding the pair).
Plus determinism (C1, bit-identical re-run of each rail) and the three bootstrap
rejections re-expressed on SourceSpec.

Gates green (re-run by the orchestrator, not just the agent): cargo build/test
(30: aura-core 19 + aura-std 3 + aura-engine 8) / clippy --workspace
--all-targets -D warnings clean; surface-purity grep (no dyn-Any / Rc / RefCell)
clean — the harness doc phrases RustAst's model without the literal tokens to
avoid self-match.

refs walking-skeleton

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-03 14:21:42 +02:00
Brummel dd5c3fad96 feat(engine): the deterministic single-source sim loop
Cycle 0003: aura-engine's first real content — a Sim that runs a wired DAG of
nodes deterministically, cycle by cycle. First point in the project where
authored nodes execute against data, not just under a hand-fed Ctx.

- `Sim` (aura-engine) — a bootstrapped, frozen root graph: a flat Vec<NodeBox>
  (each node owns its input columns, the cycle-0002 shape) + an index edge
  table, topologically ordered (Kahn). `bootstrap` sizes every input column from
  its node's schema, kind-checks each edge and source target, and rejects
  directed cycles — C7's "type check paid once at wiring" generalized to the
  whole topology (`BootstrapError::{KindMismatch, BadIndex, Cycle}`).
- `run` — the deterministic loop: per record, forward the source value into its
  target slots, evaluate nodes in topo order, capture the observed node's output
  at eval time, and forward each `Some` output into its consumers' input columns
  (a `None` forwards nothing — the structural seed of sample-and-hold). The loop
  destructures `&mut self` into disjoint field borrows and allocates nothing on
  the per-cycle path. This is the flat, monomorphized sharpening of RustAst's
  reference-counted, interior-mutable observer push graph (C1/C7).
- `Edge` / `Target` (aura-engine) — producer->consumer and source->consumer wiring.
- `Sub` (aura-std) — a 2-input f64-difference node, so the loop is proven on a
  real fan-out + join DAG (source -> {SMA(2), SMA(4)} -> Sub), with a determinism
  assertion (C1: a second identical run is bit-identical).

Engine library depends only on aura-core; a test-only dev-dependency on aura-std
lets the integration test wire real Sma/Sub nodes. Sim carries a hand-written,
node-opaque `Debug` impl (Box<dyn Node> is not Debug; the impl prints
nodes.len() + the index/topology fields, needed by the bootstrap-rejection tests'
`unwrap_err`).

Deliberately deferred (recorded as decisions): freshness-gated recompute /
sample-and-hold (C5 -> cycle 0004, with the second source that makes it testable);
the explicit monotonic cycle_id counter (its first reader is freshness, 0004);
the Source trait + data-server ingestion + k-way merge (C3/C11); the builder API
(C19); the real sink + run registry (C18/C22).

Gates green: cargo build/test (26: 18 aura-core + 3 aura-std + 5 aura-engine)/
clippy -D warnings clean; surface-purity grep (no dyn-Any / Rc / RefCell) clean.

refs walking-skeleton
2026-06-03 13:02:47 +02:00