memlnaut-nisps/codegen/README.md
monkey-w1n5t0n 7ce4598a0b chore(schemas): retire the clobbering seed script; fix the direction-of-truth text
Phase 3 (L39, ST13, ST9, ST10).

- L39: deleted codegen/seed-midi-devices.ts. It regenerated — and therefore
  silently CLOBBERED — the hand-tuned device schemas it had originally created.
  Its purpose is served and git retains it. Confirmed nothing invokes it (the
  root package.json that once might have was deleted in Phase 1).
- ST13: moved the provenance artifact out of the repo root. AUDIT CORRECTION:
  the finding's proposed destination, schemas/midi_devices/synth-midi-cc.sources.json,
  would have BROKEN codegen and CI — generate-midi-devices.ts treats every *.json
  directly under that directory as a device template and ajv-validates it, and
  the sources file has no device_id/midi/params, so the generator would exit
  non-zero. It went to schemas/midi_devices/sources/ instead.
- ST9: schemas/schema.json's own description stated the direction of truth
  BACKWARDS. Rewritten: schemas are canonical, codegen emits C++ and TypeScript.
  (The audit cited params_notes.md; the real path is schemas/modes/params_notes.md.)
- ST10: codegen/README.md rewritten against current reality — it described
  retired playground paths and a phantom temp dir.

Descriptions are never emitted, so this is behaviour-inert; proven by
regenerating all four generated directories byte-identically.
2026-07-21 14:03:07 +02:00

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Markdown

# codegen — schemas → C++ + TypeScript
Bun scripts that turn the JSON schemas under `schemas/` into generated code for both
targets. The per-file inventory lives in `MAP.md``codegen/`) — this README only
covers how to run it.
- `generate.ts` — validates `schemas/modes/*.json` against `schemas/schema.json`, emits
`nisps/modes/generated/<mode>_schema.hpp` (+ `schema_types.hpp`) and
`manifold/src/modes/generated/<mode>_schema.ts` (+ `types.ts`, `index.ts`).
- `generate-midi-devices.ts` — validates `schemas/midi_devices/*.json` against
`schemas/midi_device.schema.json`, emits `nisps/midi/generated/midi_devices.hpp` and
`manifold/src/midi-devices/generated/{types,devices,index}.ts`.
Both validate with ajv (Draft 2020-12), exit non-zero on failure, and are idempotent
(re-running with unchanged schemas is byte-identical).
## Run
```bash
cd codegen
bun install
bun run generate.ts # mode schemas
bun run generate-midi-devices.ts # MIDI device templates
```
Schema or codegen changes ship with the regenerated C++ **and** TypeScript in the same
commit — CI re-runs both generators and fails on any diff.
## Golden test
`tests/golden_test.ts` re-runs `generate.ts` against the live output dirs, diffs
`paf_synth_schema.{hpp,ts}` against the snapshots in `tests/golden/`, then re-runs to
prove idempotency:
```bash
bun run test
```
After an intentional emission change, refresh the goldens:
```bash
bun run generate.ts
cp ../nisps/modes/generated/paf_synth_schema.hpp tests/golden/
cp ../manifold/src/modes/generated/paf_synth_schema.ts tests/golden/
```
## Adding a mode / device
Drop the new JSON into `schemas/modes/` (or `schemas/midi_devices/`), run the matching
generator, and commit the JSON plus the regenerated outputs together.