# C19 — Bootstrap: blueprint → instance (recursive): history

> FROZEN HISTORICAL RECORD. Each block below was true as of its cycle/date stamp
> and may be superseded; this file is NOT current truth and NOT a grounding
> surface. Current contract: [c19-bootstrap.md](c19-bootstrap.md).

**Realization (cycle 0016 — param-set injection).** The bootstrap now binds an
injected param-set, realizing C12's "params injected at graph build (the optimizer
sees a generic vector of typed ranges)" and C19's "factory `params → sized node`"
*literally*: a blueprint leaf is **value-empty** — `BlueprintNode::Leaf` holds a
`LeafFactory { name, params, build }` recipe, not a built node — and the value lives
only in the injected vector (no baked default), so the blueprint stays a pure
param-generic recipe. (Renamed in cycle 0024: `BlueprintNode::Primitive` holds a
`PrimitiveBuilder { name, schema, build }` — the recipe now carries the full
signature, see the C8 0024 realization; `bootstrap_with_params`/`compile_with_params`
moved onto `Composite` when `struct Blueprint` collapsed into it, see the C19 0024
realization.) `bootstrap_with_params(Vec<Scalar>)` /
`compile_with_params` **build each leaf through its own constructor** (the single
sizing/validation gate) from its kind-checked slice **while lowering** (build-then-
wire), consuming the vector slot-by-slot in the *same* depth-first walk
`param_space()` projects — so the two share one traversal (subsuming the #34 dual-
traversal hazard) and the value reaches the node at the slot the sweep enumerates.
Arity is checked up front (`param_space().len()`); a wrong-kind or wrong-length
vector is a typed `CompileError::{ParamKindMismatch, ParamArity}` (the typed-value
check C8 deferred). The lowering/edge/source rewrite is structurally unchanged, so
the **flat graph stays bit-identical** for a given point (C23, the correctness
invariant). The value *domain* (e.g. `length ≥ 1`) stays the constructor's own
`assert`; the search-range is still the run's (#32/C20). One value-empty leaf
detail for C22: the blueprint view (pre-run, param-generic) labels a leaf by **bare
type** (`PrimitiveBuilder::label`, was `LeafFactory::label`, → `[SMA]`) — the
value-bearing `SMA(2)` of C8's render-
label refinement now appears only in the *compiled* view (built nodes, `Node::label`).

**Realization (cycle 0017 — blueprint render = main graph + definitions).** The
`aura graph` blueprint view (C9 graph-as-data, #13) renders the **authored
structure** as a *program with subroutines*: a flat **main graph** wiring the
harness with each composite shown as a **single opaque node** `[name]`, plus a
`where:` section that defines each **distinct** composite type **once** (its
interior with named input-entry nodes and outputs folded onto their producers as
`name := …` bindings (render refined through cycles 0019–0022; originally
`[in:k]`/`[out]` port markers); deduped by `name()`, collected
recursively so nested composites are opaque nodes with their own definitions). This
supersedes #13's original cluster-box model and is the durable split this view
realizes: **blueprint = source** (composites as named subroutines, body once) vs.
**compiled = inlined machine form** (C23, boundary dissolved). The substantive cause
for retiring cluster boxes is a real renderer defect — `ascii-dag` 0.9.1's subgraph
level-centering rounds sibling x-positions with `/2`, overlapping wide sibling
labels (width/parity-sensitive, no config/padding dodge surviving unequal-width
siblings); the **flat** layout is collision-free, and both views now build flat
graphs only. The model also scales (blueprint size tracks top-level wiring, not
inlined node count) and removes #13's nested-composite `unimplemented!` (the
definitions pass recurses). The interactive *enter/focus* counterpart (a composite
collapsed to a navigable node) is the playground's, parked as a separate concern
(#37); the static CLI keeps the all-at-once definitions form (#38).

**Realization (cycle 0024 — the root is the fully-bound composite; the flat graph is
a named type).** `struct Blueprint` is **deleted**: the root graph IS a `Composite`,
and `compile_with_params`/`bootstrap_with_params`/`param_space` are its methods.
What distinguished the root — its bound data sources — is now a property of its input
roles: `Role` carries `source: Option<ScalarKind>` (`None` = an open interior port,
wired by the enclosing graph; `Some(kind)` = a bound ingestion feed). A composite is
**runnable iff every root role is bound** (C3: sources bind at ingestion only); an
open root role is a compile-time `CompileError::UnboundRootRole`. So the "main graph"
is no longer a separate kind — only the composite all of whose roles are
source-bound, governed by the same conditions as any other node. Compilation now
targets a **named type**: `compile` validates structurally **pre-build** (via
`signature()`, no node constructed — an ill-typed wiring is caught before any build
closure fires) and emits `FlatGraph { nodes, signatures, sources, edges }` — the
C23 flat graph, now first-class — which `Harness::bootstrap` consumes (kinds/firing
from the carried signatures, buffer depth from `lookbacks()`). The per-flat-node
signature travels beside the node, so `bootstrap` reads it without a built-node
`schema()` call (which no longer exists, see the C8 0024 realization).

**Realization (cycle 0026 — graph render redesign: model + WASM-Graphviz viewer,
#51).** `aura graph` no longer renders ASCII. The render path is now two pieces:
a read-only **model serializer** (`aura_engine::model_to_json`, iteration 1) that
walks the root composite + every distinct composite type into a deterministic,
hand-rolled JSON model (C14, golden-tested; the engine's last hand-rolled JSON
writer after `RunReport::to_json` moved to serde in cycle 0033; the
swapped-param mis-wire property moved here from the old compiled-view test), and a
**self-contained HTML viewer** (`aura-cli::render::render_html`, iteration 2) that
inlines that model, the ported prototype viewer JS, and a vendored Graphviz-WASM
blob into one page emitted to stdout. Layout/SVG happen in the browser via
WebAssembly — aura ships no layout engine and stays a serializer (C9: graph-as-data,
no `eval`/build on the path). The viewer is a render asset (C10 — no node/strategy
logic, no DSL); it labels every input pin from the model's now-real names (C23
debug symbols, named in cycle 0027) and colours wires by the four scalar base
types (C4). This **retires `ascii-dag`** and its adapter (`graph.rs`), the
`--compiled`/`--macd` flag plumbing, and the invented `#Sf`/`:=`/`histogram →`
notation — superseding the cycle-0017 flat-ascii model and its renderer-defect
workaround. The DOT/SVG are Graphviz-version-dependent and not golden-tested; the
deterministic JSON model is the asserted contract.

**Realization (cycle 0034 — structural-constant bind: a knob *removed* from
param_space, #55).** `PrimitiveBuilder::bind(slot, value)` adds the **third** param
category beside the topology factory-arg (C7/C19) and the tuning param (the
cycle-0016 value-pin): a **structural constant**. The cycle-0016 binding *pins* a
value in the injected vector while the knob **stays** in `param_space` (a tuning
param the sweep varies); `bind` instead **removes** the slot from `param_space`
entirely — the knob is gone, not fixed. The discriminator is the #55
deform-vs-tune test: a value whose variation yields another valid point of the
*same* strategy is a **tuning param** (stays in `param_space`); a value whose
variation *deforms* the strategy into a different one (e.g. the `2` of an
"SMA2-entry" bound to its two-candle construction) is a **structural constant**
(bound out), so a sweep never enumerates deformed strategies as valid family
members. Mechanically `bind` shrinks the builder's declared param surface
(`schema.params`) and wraps its build closure to re-splice the constant at its
original positional slot; the construction layer
(`collect_params`/`lower_items`/`param_space`/`compile_with_params`) is
**byte-unchanged** — both dock sites already key off `builder.params()`, so the
shrink propagates for free, and chained binds reconstruct the correct positional
vector because each layer computes its slot index relative to the param list it
sees. C23 is unaffected: `bind` resolves the param **name** to a position at
**authoring** time (the by-name authoring address space, the 0032 amendment) and
the flat graph stays wired by raw index — the name never reaches it. The
complementary question — exporting a **named frozen** strategy (all/most knobs
bound) as a reusable blueprint *value* — is deferred (#60); `bind` ships only the
per-knob overlay, no registry (C9/C10 intact).