A pitch now resolves to a frequency. The tuning-resolution vocabulary
(TuningSystem, TuningResolution, TuningOverride, TuningScope), a partial built-in
catalog, and the five-scope resolver land in epiphany-core, entirely off the
wire -- the reversible half of the remaining tuning work, exercised and proven
before the schema-major-3 bump freezes anything.
Nine of twenty systems resolve: the six tet-* (EqualTemperament, each paired to
the pitch space of matching chromatic cardinality -- tet-12/cmn-12,
tet-N/edo-N), and the three ji-static-5limit-{C,G,D}, whose twelve ratios are
COMPUTED from the lattice block {3^a 5^b | a in [-1,2], b in [-1,1]} in exact
integer arithmetic, never a pasted table. The other eleven fail closed with a
distinct NotYetSupported (vs UnknownTuningSystem): the ten historical
temperaments await tranche 2b, ji-adaptive-5limit awaits HarmonicContext.
overrides is added to ScoreTuningContext as the one field the scope walk needs,
in memory only. Its struct_codec! -- whose dec constructs a literal of exactly
the named fields -- is replaced by a hand-written Codec that encodes the three
wire fields and defaults overrides on decode, with a matching hand-written
TextValue.
Verified independently of the agent that wrote it. Through the real
Score::canonical_bytes() path: a populated overrides encodes byte-identically to
an empty one (268 bytes both) and decodes back to empty -- the field never
reaches the wire. tet-12 A4=440 resolves C5 to 523.2511306011972 Hz by hand.
ji-static-5limit-C's major third is 386.3137c against tet-12's 400.0000c, the
5/4 just third distinct by the expected 13.69c. The wire-invariant test
mutation-killed by leaking the override count from the codec (the first attempt,
encoding the field itself, was a compile error since TuningOverride has no Codec
-- meaningless as a mutation, redone). No golden or fuzz digest moved.
Also corrected a doc comment on pitch.rs's sounding_equivalent that this tranche
falsified: it said frequency resolution is "not modeled in this crate", which is
now untrue.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Levi Neuwirth
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