An operation was, in the overwhelming majority of cases, four facts: what
its parameters are, what uniforms they compute, what WGSL those uniforms
drive, and where it sits in the chain. Written in Rust those four facts
arrived wrapped in ninety lines of trait implementation — a match on
parameter id to a struct field, another match back, an is_active comparing
each field to its default, a Vec<Uniform> built by hand. All mechanical,
and each one a place to make a silent mistake: a param() arm returning the
wrong field reads perfectly and breaks the sidecar round-trip.
So the four facts are the file now. core/dr-pipeline/ops/<id>.yaml is a
node, build.rs compiles it into the same Operation impl as before, and the
result lands in OUT_DIR — the same reasoning as style.yaml -> theme.slint,
including why it does not land beside the sources it would look exactly
like. Nothing downstream can tell a declared node from a hand-written one:
same &'static OpDescriptor, same fused-shader composition, same sidecar.
Nine nodes moved: exposure, white_balance, contrast, highlights_shadows,
blacks_whites, brilliance, vibrance, saturation, and the shared WGSL
helper registry. Their prose came with them, and so did their tests —
set/expect/expect_active/expect_wgsl in the declaration compile to real
#[test]s, so a node file carries its own proof rather than leaving it
behind in a file that no longer exists.
Two stayed in Rust and say so with `rust:`. The tone curve's neutral is a
relationship between five interpolated points rather than a set of values;
the colour mixer generates thirty-six faceted parameters from twelve
computed hue bands. A schema stretched to cover either would be a worse
language than Rust aimed at one caller. They still declare their position
here, because the chain's *order* is the one thing a reader comes to this
directory to learn, and an order written half in YAML and half in Rust
would be worse than either alone. default_chain() is generated from it.
Uniforms are derived by a small expression language — exp2(exposure),
blacks / 100 * 0.02 — compiled to Rust rather than interpreted, so an
unknown name or a wrong arity is a build error naming the file and the key
and the arithmetic costs nothing at runtime. The build script refuses a
duplicate order, a filename disagreeing with its id, a default outside its
own range, a test value the graph would clamp before the node saw it, a
helper that does not define the function it names, and a declared node
colliding with a file in src/ops.
Verified by adding a scratch node and removing it again: one file, no
other edit, and it joined the chain at its declared order with its test
running. 237 tests pass in dr-pipeline, clippy and fmt clean.
.yaml joins the traceability tool's scanned suffixes, because a node's
Rust now lives in OUT_DIR where a tag could never be linked from the
report. Coverage 47.7% -> 48.3%.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
dtourolleandClaude Opus 5
7c57f490fe