epiphany/crates/epiphany-core/src/pitch.rs

1459 lines
59 KiB
Rust

//! Pitch primitives and the spelling subsystem (Chapter 2; Chapter 4 for the
//! tuning/pitch-space registry identifiers a pitch references).
//!
//! A [`Pitch`] is two independent intrinsic layers (Chapter 2 §"The Pitch
//! Type"): a [`ScalePosition`] (analytical identity within a pitch space) and
//! an [`AcousticPitch`] (sounding-frequency identity, relative to a tuning
//! system). Spelling — what the performer sees — is **not** a field on the
//! pitch (Chapter 2 §"Spelling"); it is attached externally, indexed by
//! [`PitchId`], through [`SpellingAttachment`].
//!
//! Pitches embedded in events are wrapped in [`IdentifiedPitch`], pairing the
//! pitch with its stable [`PitchId`] (Chapter 5 §"Identified Pitches").
use epiphany_determinism::{
canonical_f64_bytes, CanonicalF64, SystemDomainTag, Tolerance, ToleranceClass,
};
use unicode_normalization::UnicodeNormalization;
use crate::ids::{derive_system_id, AnalysisLayerId, PitchId, VoiceId};
use crate::time::TimeAnchor;
/// Defines a catalog / registry identifier: a named entry in one of the
/// score's registries (pitch spaces, tuning systems, accidental registries,
/// …). The built-in catalog uses short ASCII names like `"cmn-12"` and
/// `"tet-12"` (Chapter 4 §"Built-in Catalog"), so the identifier is a string.
///
/// Appendix D §"Text and Unicode" makes canonical text identity byte comparison
/// of the UTF-8 **NFC** form: *"Canonical text fields MUST be encoded as UTF-8
/// with Unicode NFC applied … Comparisons of canonical text fields for identity
/// MUST be byte comparisons of NFC-encoded UTF-8."* [`$name::new`] therefore
/// **normalizes to NFC on construction**, so two canonically-equivalent names
/// (e.g. precomposed "é" U+00E9 vs decomposed "e"+U+0301) intern to the same
/// value and compare, hash, and order equal. The built-in catalog names are
/// ASCII (already NFC) and so are unaffected.
macro_rules! catalog_id {
($(#[$meta:meta])* $name:ident) => {
$(#[$meta])*
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct $name(String);
impl $name {
/// Interns a catalog name, normalizing it to Unicode NFC so
/// canonically-equivalent spellings compare equal (Appendix D
/// §"Text and Unicode").
#[inline]
pub fn new(name: impl Into<String>) -> Self {
$name(name.into().nfc().collect())
}
/// The catalog name.
#[inline]
pub fn as_str(&self) -> &str {
&self.0
}
}
impl core::fmt::Debug for $name {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
write!(f, concat!(stringify!($name), "({:?})"), self.0)
}
}
impl core::fmt::Display for $name {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
f.write_str(&self.0)
}
}
};
}
catalog_id!(
/// Identifies a pitch space (Chapter 4 §"Pitch Spaces"). Built-ins include
/// `cmn-12`, `edo-31`, `ji-5limit`.
PitchSpaceId
);
catalog_id!(
/// Identifies a tuning system (Chapter 4 §"Tuning Systems"). Built-ins
/// include `tet-12`, `werckmeister-iii`.
TuningSystemId
);
catalog_id!(
/// Identifies an accidental registry (Chapter 4 §"Accidental Registries").
AccidentalRegistryId
);
catalog_id!(
/// Identifies an accidental within a registry (Chapter 4).
AccidentalId
);
catalog_id!(
/// Identifies a nominal registry (Chapter 4).
NominalRegistryId
);
catalog_id!(
/// Identifies a registered (grammar-defined) scale position
/// (Chapter 2 §"Scale Position").
PositionRegistryId
);
catalog_id!(
/// Identifies a registered tie class with custom validation behaviour
/// (Chapter 5 §"Ties", `TieClass::Registered`).
TieClassRegistryId
);
catalog_id!(
/// Identifies a registered staff-group kind (Chapter 5
/// §"Top-Level Score Structure", `StaffGroupKind::Registered`).
StaffGroupKindRegistryId
);
catalog_id!(
/// Identifies a spelling rule set (Chapter 4 §"Spelling Rule Sets").
SpellingRuleSetId
);
catalog_id!(
/// Identifies a spelling algorithm family (Chapter 2 §"The Spelling
/// Pre-Pass"). The v0 stub registers [`SpellingAlgorithmId::default_id`].
SpellingAlgorithmId
);
catalog_id!(
/// Identifies a notational-decomposition algorithm family (Chapter 3
/// §"Sounding Duration and Notational Decomposition"). Versioned the same
/// way as [`SpellingAlgorithmId`]: the id is part of the derivation key for
/// the decomposition pre-pass, so a profile-declared change deterministically
/// invalidates derived decompositions. The Phase-2 default
/// ([`DecompositionAlgorithmId::default_id`]) resolves to the metric
/// greedy-aligned splitter in [`crate::prepass`].
DecompositionAlgorithmId
);
catalog_id!(
/// Identifies a foreign interchange format (e.g. MusicXML), used as a
/// spelling/decomposition provenance tag.
ForeignFormatId
);
impl SpellingAlgorithmId {
/// The Phase-2 default spelling algorithm, registered under the id
/// `"default"`. The id resolves to the deterministic Temperley-style
/// line-of-fifths pre-pass implemented in [`crate::prepass`] (Chapter 2
/// §"The Spelling Pre-Pass"). The literal id is part of the derivation key:
/// changing the registered algorithm changes the id, so derived spellings
/// computed under a different version never silently alias.
pub fn default_id() -> Self {
SpellingAlgorithmId::new("default")
}
}
impl DecompositionAlgorithmId {
/// The Phase-2 default decomposition algorithm, registered under the id
/// `"default"`. The id resolves to the deterministic metric greedy-aligned
/// splitter implemented in [`crate::prepass`] (Chapter 3 §"Sounding Duration
/// and Notational Decomposition").
pub fn default_id() -> Self {
DecompositionAlgorithmId::new("default")
}
}
/// The seven CMN diatonic nominals. The discriminants are **normative**: they
/// define the diatonic step ordering used by transposition (Chapter 2
/// §"The CmnNominal Type").
#[repr(u8)]
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
pub enum CmnNominal {
C = 0,
D = 1,
E = 2,
F = 3,
G = 4,
A = 5,
B = 6,
}
impl CmnNominal {
/// The nominal's position in the 12-chromatic layer for `cmn-12`
/// (`C=0, D=2, E=4, F=5, G=7, A=9, B=11`), per the
/// `DiatonicOverChromatic` mapping in Chapter 4.
pub fn chromatic(self) -> u8 {
match self {
CmnNominal::C => 0,
CmnNominal::D => 2,
CmnNominal::E => 4,
CmnNominal::F => 5,
CmnNominal::G => 7,
CmnNominal::A => 9,
CmnNominal::B => 11,
}
}
/// The nominal for a diatonic index in `0..7`, the inverse of the type's
/// normative discriminant (Chapter 2 §"The CmnNominal Type"). Panics
/// outside the range; callers reduce with `rem_euclid(7)` first.
fn from_index(index: i32) -> Self {
match index {
0 => CmnNominal::C,
1 => CmnNominal::D,
2 => CmnNominal::E,
3 => CmnNominal::F,
4 => CmnNominal::G,
5 => CmnNominal::A,
6 => CmnNominal::B,
other => unreachable!("diatonic index out of 0..7: {other}"),
}
}
}
/// A signed interval: the transposition primitive (Chapter 2
/// §"Transposition and the Interval Type"; schema major 2). Both components
/// are load-bearing — the diatonic one fixes the spelling (which nominal,
/// hence which staff line), the chromatic one fixes the sound. Neither
/// determines the other: an augmented second `(1, 3)` and a minor third
/// `(2, 3)` sound alike and are written differently.
///
/// [`Instrument::transposition`](crate::Instrument) carries one as its
/// written-versus-sounding interval (a B-flat clarinet is `-1` diatonic, `-2`
/// chromatic). Its *action* is pinned by [`Pitch::transposed`]; what stays
/// advisory is its automatic application at the written/sounding boundary,
/// which nothing in the core performs yet.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub struct TranspositionInterval {
pub diatonic_steps: i32,
pub chromatic_steps: i32,
}
impl TranspositionInterval {
/// The interval that undoes this one, or `None` when it is not
/// representable: `i32::MIN` has no `i32` negation. Exact where it exists,
/// because [`Pitch::transposed`] never saturates — it refuses instead.
///
/// The non-representable case is explicit rather than a panic or a wrap:
/// an interval whose inverse cannot be written down is a fact about the
/// type, and a caller composing undo out of inverses must see it.
pub fn inverse(self) -> Option<Self> {
Some(TranspositionInterval {
diatonic_steps: self.diatonic_steps.checked_neg()?,
chromatic_steps: self.chromatic_steps.checked_neg()?,
})
}
}
/// Why a pitch could not be faithfully transposed (Chapter 2
/// `req:pitch:transposition`). Each variant is a way a transposition would
/// otherwise have to lie.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum TransposeRefusal {
/// The position is not [`PitchSpacePosition::Cmn`], so it has no nominal
/// for the interval's diatonic component to move.
NonCmnPosition,
/// The pitch's [`AcousticRealization::AbsoluteHz`] overrides the tuning
/// system, so moving the scale position would move the notehead without
/// moving the sound.
AcousticPinned,
/// The resulting `alteration` or `octave` does not fit its `i8` field.
OutOfRange,
}
impl Pitch {
/// Transposes this pitch by `interval`, per Chapter 2
/// `req:pitch:transposition`.
///
/// With `n` the nominal's normative discriminant and the absolute semitone
/// `s = nominal.chromatic() + alteration + 12*octave`, transposing by
/// `{ d, c }` yields
///
/// ```text
/// nominal' = CmnNominal((n + d).rem_euclid(7))
/// octave' = octave + (n + d).div_euclid(7)
/// alteration' = (s + c) - (nominal'.chromatic() + 12*octave')
/// ```
///
/// The diatonic component alone selects the nominal and octave; the
/// alteration absorbs exactly the residue. So `C4 + (7, 12)` is `C5`, not
/// "C with twelve sharps", and `C4 + (0, 1)` is `C#4`.
///
/// Refuses rather than saturating, clamping, or approximating: a
/// transposition that silently produces a pitch nobody asked for reports
/// success and destroys the evidence needed to notice.
pub fn transposed(&self, interval: TranspositionInterval) -> Result<Pitch, TransposeRefusal> {
if matches!(
self.acoustic.realization,
AcousticRealization::AbsoluteHz(_)
) {
return Err(TransposeRefusal::AcousticPinned);
}
let PitchSpacePosition::Cmn {
nominal,
alteration,
octave,
} = self.scale_position.position
else {
return Err(TransposeRefusal::NonCmnPosition);
};
// Widen to `i64` before any arithmetic. The `i8` bound is a *result*
// constraint, not an intermediate one, so an octave that overflows on
// the way to a value that fits would be a spurious refusal — but
// `i32` is not wide enough to hold the intermediates for an `i32`
// interval, and the previous version of this function panicked on
// `diatonic_steps = i32::MAX` at `12 * new_octave`. Refusing is the
// contract; panicking on a value the public type admits is not.
//
// `i64` is amply wide: `step` is bounded by `6 + 2^31`, so
// `new_octave` by `2^31/7 + 127`, and the largest intermediate
// `12 * new_octave` by roughly `3.7e9`.
let n = i64::from(nominal as u8);
let semitone =
i64::from(nominal.chromatic()) + i64::from(alteration) + 12 * i64::from(octave);
let step = n + i64::from(interval.diatonic_steps);
let new_nominal = CmnNominal::from_index(step.rem_euclid(7) as i32);
let new_octave = i64::from(octave) + step.div_euclid(7);
let new_alteration = (semitone + i64::from(interval.chromatic_steps))
- (i64::from(new_nominal.chromatic()) + 12 * new_octave);
let octave = i8::try_from(new_octave).map_err(|_| TransposeRefusal::OutOfRange)?;
let alteration = i8::try_from(new_alteration).map_err(|_| TransposeRefusal::OutOfRange)?;
let mut out = self.clone();
out.scale_position.position = PitchSpacePosition::Cmn {
nominal: new_nominal,
alteration,
octave,
};
Ok(out)
}
}
/// A position within a pitch space (Chapter 2 §"Scale Position"). Tagged union
/// with a fast CMN path plus a registry escape hatch for arbitrary grammars.
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub enum PitchSpacePosition {
/// Common Music Notation: diatonic nominal + chromatic alteration + octave.
Cmn {
nominal: CmnNominal,
/// Chromatic alteration in semitones, conventionally `-2..=+2`.
alteration: i8,
/// Scientific Pitch Notation octave; middle C is C4.
octave: i8,
},
/// N-tone integer position (serial, EDO).
Integer { space_size: u16, index: i32 },
/// Just-intonation lattice vector; one exponent per prime in the space's
/// declared basis (Chapter 2 §"Scale Position", `JiVector`).
JiVector { components: Vec<i32> },
/// A registered position resolved by the pitch space's grammar plugin.
Registered(PositionRegistryId),
}
/// A pitch's analytical identity (Chapter 2 §"Scale Position").
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct ScalePosition {
/// The pitch space this position is defined within.
pub space: PitchSpaceId,
/// The position within that space.
pub position: PitchSpacePosition,
}
/// A reference to the tuning system governing a pitch (Chapter 2
/// §"Tuning Reference and Inheritance").
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub enum TuningReference {
/// Inherit the tuning system from the enclosing scope. Malformed at score
/// level (the score's tuning system must be explicit).
Inherit,
/// Explicitly named tuning system.
Explicit(TuningSystemId),
}
/// How the tuning system resolves to a frequency (Chapter 2 §"Acoustic
/// Realization"). The cents/Hz payloads are [`CanonicalF64`] so a NaN/inf/`-0.0`
/// can never enter canonical state (Appendix D §"Floating-Point Values").
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
pub enum AcousticRealization {
/// Resolve through the tuning system using the scale position alone (the
/// default for ordinary CMN).
Implicit,
/// An explicit offset in cents from the tuning system's result.
CentsOffset(CanonicalF64),
/// An explicit absolute frequency in Hertz, overriding the tuning system.
AbsoluteHz(CanonicalF64),
}
impl AcousticRealization {
/// Builds a cents offset, rejecting a non-finite value (Appendix D).
pub fn cents_offset(cents: f64) -> Option<Self> {
CanonicalF64::new(cents).map(AcousticRealization::CentsOffset)
}
/// Builds an absolute-frequency realization, rejecting a non-finite or
/// non-positive frequency (Chapter 4 §"Reference Pitch": "positive and
/// finite").
pub fn absolute_hz(hz: f64) -> Option<Self> {
if hz > 0.0 {
CanonicalF64::new(hz).map(AcousticRealization::AbsoluteHz)
} else {
None
}
}
}
/// The reference pitch anchoring a tuning system's ratios to absolute Hertz
/// (Chapter 4 §"Reference Pitch"). A score-level property, not a tuning-system
/// one. The frequency is a finite, positive [`CanonicalF64`].
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct ReferencePitch {
/// The pitch-space position chosen as the reference (conventionally A4).
pub position: PitchSpacePosition,
/// The frequency in Hertz; **positive** and finite. Private so it cannot be
/// mutated into an invalid value after construction (Chapter 4: "positive
/// and finite") — the only way to set it is through [`ReferencePitch::new`].
frequency_hz: CanonicalF64,
}
impl ReferencePitch {
/// Builds a reference pitch, rejecting a non-finite or non-positive
/// frequency (Chapter 4: "positive and finite").
pub fn new(position: PitchSpacePosition, frequency_hz: f64) -> Option<Self> {
if frequency_hz > 0.0 {
CanonicalF64::new(frequency_hz).map(|frequency_hz| ReferencePitch {
position,
frequency_hz,
})
} else {
None
}
}
/// The reference frequency in Hertz (always positive and finite).
#[inline]
pub fn frequency_hz(&self) -> f64 {
self.frequency_hz.get()
}
/// The conventional default: A4 = 440 Hz in `cmn-12` (Chapter 4 §"Default
/// Score Configuration").
pub fn a440() -> Self {
ReferencePitch::new(
PitchSpacePosition::Cmn {
nominal: CmnNominal::A,
alteration: 0,
octave: 4,
},
440.0,
)
.expect("A4=440 is a valid reference pitch")
}
}
/// A pitch's acoustic identity (Chapter 2 §"Acoustic Realization").
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct AcousticPitch {
/// The tuning system governing this pitch's frequency.
pub tuning: TuningReference,
/// How the tuning system resolves to a frequency.
pub realization: AcousticRealization,
}
/// A pitch's intrinsic identity: scale position plus acoustic realization
/// (Chapter 2 §"The Pitch Type"). Spellings are attached externally.
///
/// Derived `Eq` is **structural equality** (Chapter 2 §"Equality and
/// Comparison"). The computed equivalences — scale-position and enharmonic —
/// are separate methods and must never be conflated with structural equality.
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct Pitch {
/// The analytical identity within a pitch space.
pub scale_position: ScalePosition,
/// The acoustic identity.
pub acoustic: AcousticPitch,
}
impl Pitch {
/// Scale-position equivalence (Chapter 2): equal `ScalePosition` fields,
/// ignoring acoustic realization. Exact; never tolerant.
pub fn scale_position_equivalent(&self, other: &Pitch) -> bool {
self.scale_position == other.scale_position
}
/// The 12-TET pitch class (`0..=11`) of this pitch's *scale position*, when
/// that is computable from the position alone: CMN positions and 12-EDO
/// integer positions. Returns `None` for positions whose 12-TET class is
/// not determinable without a tuning resolver (JI vectors, non-12 EDOs,
/// registered grammars). Octave-blind — for sounding comparison use
/// [`Pitch::twelve_tet_semitone`].
pub fn twelve_tet_class(&self) -> Option<u8> {
self.twelve_tet_semitone().map(|s| s.rem_euclid(12) as u8)
}
/// The *absolute* 12-TET semitone of this pitch's scale position, octave
/// included, when computable from the position alone. For CMN this is
/// `octave*12 + nominal.chromatic() + alteration` (so C4 and C5 differ by a
/// full octave); for 12-EDO integer positions it is the absolute `index`.
/// `None` for positions not determinable without a tuning resolver.
///
/// The CMN and 12-EDO frames use different zero references, so the absolute
/// value is only meaningful *within* a frame; [`Pitch::enharmonic_equivalent`]
/// compares only same-frame positions for that reason.
pub fn twelve_tet_semitone(&self) -> Option<i32> {
match &self.scale_position.position {
PitchSpacePosition::Cmn {
nominal,
alteration,
octave,
} => Some(*octave as i32 * 12 + nominal.chromatic() as i32 + *alteration as i32),
PitchSpacePosition::Integer { space_size, index } if *space_size == 12 => Some(*index),
_ => None,
}
}
/// Enharmonic equivalence (Chapter 2): sounding-equivalent under 12-tone
/// equal temperament, regardless of the actual tuning system. This is a
/// *sounding* notion, so octave matters — C4 and C5 are **not**
/// enharmonically equivalent (they sound an octave apart); C-sharp4 and
/// D-flat4 are. Computed from the absolute 12-TET semitone
/// ([`Pitch::twelve_tet_semitone`]).
///
/// Pitches in **different pitch spaces** are not directly comparable
/// (Chapter 2 §"Scale Position": "pitches in different spaces cannot be
/// directly compared and operations between them MUST go through an explicit
/// space-conversion mechanism"), so this returns `false` unless both share a
/// [`ScalePosition::space`]. The two computable frames (CMN, 12-EDO integer)
/// also use different zero references, so a cross-frame pair returns `false`
/// too. `false` for non-determinable positions.
///
/// General *sounding* equivalence across arbitrary tuning systems is
/// [`Pitch::sounding_equivalent`].
pub fn enharmonic_equivalent(&self, other: &Pitch) -> bool {
if self.scale_position.space != other.scale_position.space {
return false;
}
match (self.twelve_tet_semitone(), other.twelve_tet_semitone()) {
(Some(a), Some(b)) => a == b,
_ => false,
}
}
/// Sounding equivalence (Chapter 2's third computed relation): two pitches
/// are sounding-equivalent if they resolve to the same frequency under their
/// respective tuning systems, within a [`Tolerance`] of the named
/// [`ToleranceClass::AcousticCents`] class.
///
/// The tolerance is the named class, not a raw `f64`: Appendix D §"Tolerance
/// Classes" forbids ad-hoc epsilons, and a [`Tolerance`] cannot carry
/// infinity or NaN ([`epiphany_determinism::CanonicalF64`] bounds). A
/// tolerance of any *other* class is a category error and never matches.
///
/// Frequency resolution in general depends on the full tuning-system catalog
/// and reference pitch — a separate subsystem (the acoustic engine,
/// Chapter 1; see `DECISIONS.md`), not modeled in this crate. Callers at that
/// layer pass a `resolve` closure mapping a pitch to its frequency in Hertz
/// (`None` if it cannot resolve it). An [`AcousticRealization::AbsoluteHz`]
/// pitch resolves to its own stated frequency without the closure. Returns
/// `false` if either frequency is unavailable.
pub fn sounding_equivalent(
&self,
other: &Pitch,
tolerance: Tolerance,
mut resolve: impl FnMut(&Pitch) -> Option<f64>,
) -> bool {
// The comparison is in cents, so it MUST use the AcousticCents class
// (Appendix D); a tolerance of any other class never matches.
if tolerance.class != ToleranceClass::AcousticCents {
return false;
}
let freq = |p: &Pitch, resolve: &mut dyn FnMut(&Pitch) -> Option<f64>| -> Option<f64> {
match p.acoustic.realization {
AcousticRealization::AbsoluteHz(hz) => Some(hz.get()),
_ => resolve(p),
}
};
let mut r = &mut resolve;
match (freq(self, &mut r), freq(other, &mut r)) {
(Some(a), Some(b)) if a > 0.0 && b > 0.0 => {
// Compare in cents against zero: |1200·log2(a/b)| within
// tolerance. `Tolerance::within` rejects a non-finite cents
// value (e.g. an infinite resolved frequency), so the comparison
// can never be spuriously satisfied. This is a derived, tolerant
// comparison (never canonical state), so the transcendental is
// admissible (Appendix D applies to canonical numeric output).
let cents = 1200.0 * (a / b).log2().abs();
tolerance.within(cents, 0.0)
}
_ => false,
}
}
}
/// A closed pitch range, `lowest..=highest` (Chapter 2; the type
/// `core_spec` references for [`Instrument`](crate::Instrument)'s declared
/// range). Both endpoints are full [`Pitch`] values, so a range is expressed in
/// a specific pitch space; membership is only decidable when a candidate shares
/// a comparison frame with the endpoints (the same "sound but incomplete"
/// discipline as [`Pitch::enharmonic_equivalent`]). Derived `Eq` is structural.
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct PitchRange {
/// The lowest sounding pitch admitted (inclusive).
pub lowest: Pitch,
/// The highest sounding pitch admitted (inclusive).
pub highest: Pitch,
}
impl PitchRange {
/// Whether `pitch` lies within `lowest..=highest`, decided by absolute
/// 12-TET semitone ([`Pitch::twelve_tet_semitone`]). Returns `None` — the
/// indeterminate case its advisory caller treats as a pass — when:
///
/// * the three pitches do not all share a [`PitchSpaceId`] frame (absolute
/// semitones across frames use different zero references and are not
/// comparable);
/// * any pitch's semitone is not determinable without a tuning resolver; or
/// * the range is **malformed** in the comparable frame — `lowest` sorts
/// strictly above `highest`. A range is well-formed only when `lowest`
/// does not sort above `highest` (core spec §"Instrument"); a reversed
/// range is undecidable, not "empty", so it must not reject every pitch.
pub fn contains(&self, pitch: &Pitch) -> Option<bool> {
let frame = &self.lowest.scale_position.space;
if &self.highest.scale_position.space != frame || &pitch.scale_position.space != frame {
return None;
}
let lo = self.lowest.twelve_tet_semitone()?;
let hi = self.highest.twelve_tet_semitone()?;
if lo > hi {
return None; // malformed (reversed) range: undecidable, not empty
}
let p = pitch.twelve_tet_semitone()?;
Some(lo <= p && p <= hi)
}
}
/// Canonical, deterministic bytes for a [`Pitch`]'s intrinsic content (scale
/// position plus acoustic realization), used to derive a content-addressed
/// system pitch identifier. Strings are length-prefixed and already NFC (the
/// catalog ids normalize on construction); the layout is fixed-shape so equal
/// pitches encode to equal bytes (Appendix D §"Canonical serialization").
///
/// Public because these bytes are the normative "canonical inputs" of the
/// `MUSCSPCH` derivation (`req:graph:system-derived-pitch-id`): the reduction's
/// system-derived counter-collision check (Chapter 5 §"System-Derived Counter
/// Collisions") compares exactly these input bytes to distinguish two pitches
/// contending for one derived counter.
pub fn canonical_pitch_bytes(p: &Pitch) -> Vec<u8> {
// Length-prefixed UTF-8, normalized to NFC at the derivation boundary so the
// canonical input is NFC regardless of how the string was obtained (Appendix
// D §"Text and Unicode"). Catalog ids are already NFC at construction, so this
// is a no-op for them; normalizing here makes the NFC guarantee explicit and
// robust rather than relying on every caller.
fn push_str(out: &mut Vec<u8>, s: &str) {
let nfc: String = s.nfc().collect();
out.extend_from_slice(&(nfc.len() as u32).to_le_bytes());
out.extend_from_slice(nfc.as_bytes());
}
let mut out = Vec::new();
push_str(&mut out, p.scale_position.space.as_str());
match &p.scale_position.position {
PitchSpacePosition::Cmn {
nominal,
alteration,
octave,
} => {
out.push(0);
out.push(*nominal as u8);
out.extend_from_slice(&alteration.to_le_bytes());
out.extend_from_slice(&octave.to_le_bytes());
}
PitchSpacePosition::Integer { space_size, index } => {
out.push(1);
out.extend_from_slice(&space_size.to_le_bytes());
out.extend_from_slice(&index.to_le_bytes());
}
PitchSpacePosition::JiVector { components } => {
out.push(2);
out.extend_from_slice(&(components.len() as u32).to_le_bytes());
for c in components {
out.extend_from_slice(&c.to_le_bytes());
}
}
PitchSpacePosition::Registered(id) => {
out.push(3);
push_str(&mut out, id.as_str());
}
}
match &p.acoustic.tuning {
TuningReference::Inherit => out.push(0),
TuningReference::Explicit(t) => {
out.push(1);
push_str(&mut out, t.as_str());
}
}
let f64_bytes = |x: f64| canonical_f64_bytes(x).expect("CanonicalF64 is finite");
match &p.acoustic.realization {
AcousticRealization::Implicit => out.push(0),
AcousticRealization::CentsOffset(c) => {
out.push(1);
out.extend_from_slice(&f64_bytes(c.get()));
}
AcousticRealization::AbsoluteHz(h) => {
out.push(2);
out.extend_from_slice(&f64_bytes(h.get()));
}
}
out
}
/// Derives the deterministic [`PitchId`] of a *system-derived* (synthetic)
/// pitch in the [`crate::ReplicaId::SYSTEM_DERIVED`] namespace, content-addressed
/// from the pitch's intrinsic identity via the `MUSCSPCH` domain tag (Chapter 5
/// §"System-Derived Identifiers").
///
/// The spec defers the exact derivation function for synthetic pitches; this is
/// the prototype's concrete realization — the canonical inputs are the pitch's
/// content bytes (`canonical_pitch_bytes`) — so two replicas synthesizing the same pitch
/// derive a byte-identical id. Recorded as a Pass 11 candidate in `DECISIONS.md`
/// (mirrors [`crate::derive_promoted_voice_id`]). The graph-invariant checker
/// uses it to prove a `SYSTEM_DERIVED` embedded pitch is a legitimate
/// derivation rather than an arbitrary counter.
pub fn derive_system_pitch_id(p: &Pitch) -> PitchId {
derive_system_id::<PitchId>(SystemDomainTag::PITCH, &canonical_pitch_bytes(p))
}
/// A pitch embedded in an event, paired with its stable identifier (Chapter 5
/// §"Identified Pitches"). The identifier enables spelling attachments,
/// respelling, pitch-level reduction, and stable tie pairing through chord
/// reordering.
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct IdentifiedPitch {
pub id: PitchId,
pub pitch: Pitch,
}
/// The staff position (nominal) a spelling draws on (Chapter 2 §"The Spelling
/// Attachment").
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub enum SpellingNominal {
/// CMN nominal (the fast path).
Cmn(CmnNominal),
/// Integer nominal for N-tone systems.
Integer(i32),
/// Registered nominal for grammar-specific systems.
Registered(NominalRegistryId),
}
/// Optional rendering hints on a spelling (Chapter 2). Non-normative for
/// sounding pitch.
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, Default)]
pub struct SpellingRenderHints {
pub parenthesized: bool,
pub cautionary: bool,
pub editorial: bool,
pub small_print: bool,
}
/// An explicit spelling for a pitch: staff position, accidental stack, octave,
/// and render hints (Chapter 2 §"The Spelling Attachment").
///
/// The `accidentals` stack is ordered innermost-first for engraving; an empty
/// stack means *no glyph is drawn*, which is distinct from a stack containing
/// only a natural sign (Chapter 2 §"Absent Accidentals"). The accidental-stack
/// well-formedness rule (no repeated [`AccidentalId`] unless the accidental's
/// registered combination permits it) is checked by
/// [`PitchSpelling::accidental_stack_is_well_formed`].
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct PitchSpelling {
pub nominal: SpellingNominal,
/// Accidental stack, innermost (closest to the notehead) first.
pub accidentals: Vec<AccidentalId>,
pub octave: i8,
pub render_hints: SpellingRenderHints,
}
impl PitchSpelling {
/// A bare CMN spelling with no accidental glyph at the given octave.
pub fn cmn(nominal: CmnNominal, octave: i8) -> Self {
PitchSpelling {
nominal: SpellingNominal::Cmn(nominal),
accidentals: Vec::new(),
octave,
render_hints: SpellingRenderHints::default(),
}
}
/// Whether the accidental stack is free of repeated identifiers. The
/// conventional double-sharp/double-flat are single accidental
/// definitions, never repeated singles (Chapter 2 §"Accidental Stack
/// Semantics"). Registered accidentals that permit repetition are out of
/// scope for this baseline check.
pub fn accidental_stack_is_well_formed(&self) -> bool {
let mut seen = std::collections::BTreeSet::new();
self.accidentals.iter().all(|a| seen.insert(a.clone()))
}
}
/// Provenance of a spelling attachment (Chapter 2 §"Spelling Sources").
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub enum SpellingSource {
/// The user explicitly chose this spelling.
UserChosen,
/// Inferred by the spelling pre-pass. Lowest default precedence.
Inferred,
/// Imported from a foreign format.
Imported { format: ForeignFormatId },
/// Propagated from a transposition or other edit.
Propagated { from: PitchId },
/// An analytical spelling on a non-engraved layer.
Analytical,
}
/// The provenance *kind* of a spelling source, for precedence ordering
/// (Chapter 2 §"Configurable Precedence").
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
pub enum SpellingSourceKind {
UserChosen,
Imported,
Propagated,
Inferred,
Analytical,
}
impl SpellingSource {
/// The precedence kind of this source.
pub fn kind(&self) -> SpellingSourceKind {
match self {
SpellingSource::UserChosen => SpellingSourceKind::UserChosen,
SpellingSource::Imported { .. } => SpellingSourceKind::Imported,
SpellingSource::Propagated { .. } => SpellingSourceKind::Propagated,
SpellingSource::Inferred => SpellingSourceKind::Inferred,
SpellingSource::Analytical => SpellingSourceKind::Analytical,
}
}
}
/// A score's spelling-precedence configuration: a total ordering over the
/// spelling-source kinds (Chapter 2 §"Configurable Precedence"). Earlier in the
/// `order` vector wins. Every score must carry one; the default ranks
/// `UserChosen > Imported > Propagated > Inferred`, with `Analytical` last
/// (analytical spellings live on their own layers).
#[derive(Clone, PartialEq, Eq, Debug)]
pub struct SpellingPrecedence {
order: Vec<SpellingSourceKind>,
}
impl Default for SpellingPrecedence {
fn default() -> Self {
SpellingPrecedence {
order: vec![
SpellingSourceKind::UserChosen,
SpellingSourceKind::Imported,
SpellingSourceKind::Propagated,
SpellingSourceKind::Inferred,
SpellingSourceKind::Analytical,
],
}
}
}
impl SpellingPrecedence {
/// Builds a precedence from a total order. Returns `None` unless every
/// source kind appears exactly once (the spec requires a *total* ordering).
pub fn new(order: Vec<SpellingSourceKind>) -> Option<Self> {
let mut seen = std::collections::BTreeSet::new();
if order.len() != 5 || !order.iter().all(|k| seen.insert(*k)) {
return None;
}
Some(SpellingPrecedence { order })
}
/// The precedence order, for the canonical codec.
pub(crate) fn order_ref(&self) -> &[SpellingSourceKind] {
&self.order
}
/// The rank of a source kind: lower wins. `0` is the highest precedence.
pub fn rank(&self, kind: SpellingSourceKind) -> usize {
self.order
.iter()
.position(|k| *k == kind)
.expect("precedence is total over all source kinds")
}
}
/// A voice selector for scope-level directives (Chapter 2 §"Spelling
/// Attachment"; completed in Chapter 6). Minimal baseline: all voices, or an
/// explicit set.
#[derive(Clone, PartialEq, Eq, Hash, Debug, Default)]
pub enum VoiceSelector {
/// Every voice in scope.
#[default]
All,
/// An explicit set of voices.
Voices(Vec<VoiceId>),
}
/// A rule for inferring spellings within a scope (Chapter 2 §"Spelling
/// Attachment"). Baseline placeholder referencing a rule set; the rule
/// parameters are the spelling-pre-pass open question (Appendix D).
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct SpellingRule {
pub rule_set: SpellingRuleSetId,
}
/// What a spelling attachment applies to (Chapter 2).
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub enum SpellingScope {
/// Applies to one specific pitch.
Pitch(PitchId),
/// Applies to all matching pitches in a time range.
Range {
start: TimeAnchor,
end: TimeAnchor,
voices: VoiceSelector,
},
}
/// A spelling directive: an explicit spelling or an inference rule (Chapter 2).
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub enum SpellingDirective {
/// An explicit spelling for a single pitch. Only valid with
/// [`SpellingScope::Pitch`].
Explicit(PitchSpelling),
/// A rule for inferring spellings within a scope.
Rule(SpellingRule),
}
/// An externally-stored spelling, indexed by pitch identifier (Chapter 2
/// §"The Spelling Attachment").
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
pub struct SpellingAttachment {
pub scope: SpellingScope,
pub directive: SpellingDirective,
pub source: SpellingSource,
/// Tie-break priority among attachments; higher wins (after precedence).
pub priority: i32,
/// Analysis layer; `None` is the engraved layer.
pub layer: Option<AnalysisLayerId>,
}
impl SpellingAttachment {
/// Whether this attachment is internally well-formed: an
/// [`SpellingDirective::Explicit`] directive is valid only with a
/// [`SpellingScope::Pitch`] scope (Chapter 2: "Only valid with
/// SpellingScope::Pitch").
pub fn is_well_formed(&self) -> bool {
!matches!(
(&self.scope, &self.directive),
(SpellingScope::Range { .. }, SpellingDirective::Explicit(_))
)
}
}
/// Context consumed by the spelling pre-pass (Chapter 2 §"The Spelling
/// Pre-Pass"). Baseline placeholder; the real context (key signature,
/// in-measure accidental state, melodic/harmonic context) is filled in once the
/// pre-pass algorithm receives an Appendix D disposition.
#[derive(Clone, Debug, Default)]
pub struct SpellingContext {
/// The pitch space active for the pitch being spelled.
pub space: Option<PitchSpaceId>,
}
/// The context-free spelling of a single pitch: its authored CMN letter if it
/// has one, else the simplest (fewest-accidental) enharmonic spelling of its
/// 12-TET pitch class (Chapter 2 §"The Spelling Pre-Pass").
///
/// This is the *isolated* entry point. Real, context-aware spelling — the
/// Temperley line-of-fifths pre-pass that resolves a pitch by its melodic
/// neighbours — is a function of the whole score and lives in
/// [`crate::prepass::derive_annotations`]; the `_ctx` argument is retained for
/// source compatibility. A pitch whose space declares spelling unavailable
/// (no determinable 12-TET class) falls back to a middle-C advisory default.
pub fn spell(p: &Pitch, _ctx: &SpellingContext) -> PitchSpelling {
crate::prepass::simplest_spelling(p).unwrap_or_else(|| PitchSpelling::cmn(CmnNominal::C, 4))
}
#[cfg(test)]
mod tests {
use super::*;
fn cmn(nominal: CmnNominal, alteration: i8, octave: i8) -> Pitch {
Pitch {
scale_position: ScalePosition {
space: PitchSpaceId::new("cmn-12"),
position: PitchSpacePosition::Cmn {
nominal,
alteration,
octave,
},
},
acoustic: AcousticPitch {
tuning: TuningReference::Inherit,
realization: AcousticRealization::Implicit,
},
}
}
#[test]
fn cmn_nominal_discriminants_are_normative() {
assert_eq!(CmnNominal::C as u8, 0);
assert_eq!(CmnNominal::B as u8, 6);
// The cmn-12 chromatic mapping.
assert_eq!(CmnNominal::C.chromatic(), 0);
assert_eq!(CmnNominal::E.chromatic(), 4);
assert_eq!(CmnNominal::B.chromatic(), 11);
}
fn iv(diatonic_steps: i32, chromatic_steps: i32) -> TranspositionInterval {
TranspositionInterval {
diatonic_steps,
chromatic_steps,
}
}
fn position(p: &Pitch) -> (CmnNominal, i8, i8) {
match p.scale_position.position {
PitchSpacePosition::Cmn {
nominal,
alteration,
octave,
} => (nominal, alteration, octave),
ref other => panic!("expected a Cmn position, got {other:?}"),
}
}
#[test]
fn transposing_an_octave_moves_the_octave_not_the_alteration() {
// The P12-K2 defect, locked: the old alteration-shift produced
// `C4 alteration 12` — a C with six double-sharps — for this input.
let up = cmn(CmnNominal::C, 0, 4).transposed(iv(7, 12)).unwrap();
assert_eq!(position(&up), (CmnNominal::C, 0, 5));
let down = cmn(CmnNominal::C, 0, 4).transposed(iv(-7, -12)).unwrap();
assert_eq!(position(&down), (CmnNominal::C, 0, 3));
}
#[test]
fn the_diatonic_component_picks_the_nominal_and_the_alteration_absorbs_the_rest() {
// A perfect fifth up: C4 -> G4, no accidental.
let fifth = cmn(CmnNominal::C, 0, 4).transposed(iv(4, 7)).unwrap();
assert_eq!(position(&fifth), (CmnNominal::G, 0, 4));
// A *diminished* sixth up sounds the same and is spelled a step away.
let dim6 = cmn(CmnNominal::C, 0, 4).transposed(iv(5, 7)).unwrap();
assert_eq!(position(&dim6), (CmnNominal::A, -2, 4));
// Sharpening: the editor's `transpose_selection(1)` equivalent. This
// is the one case the frozen operation already got right.
let sharp = cmn(CmnNominal::C, 0, 4).transposed(iv(0, 1)).unwrap();
assert_eq!(position(&sharp), (CmnNominal::C, 1, 4));
}
#[test]
fn transposition_crosses_the_octave_boundary_in_both_directions() {
// B4 up a semitone spelled as a diatonic step: C5, not B#4.
let up = cmn(CmnNominal::B, 0, 4).transposed(iv(1, 1)).unwrap();
assert_eq!(position(&up), (CmnNominal::C, 0, 5));
// C4 down a diatonic step: B3. Euclidean, so the negative index wraps
// to 6 and the octave carries -1.
let down = cmn(CmnNominal::C, 0, 4).transposed(iv(-1, -1)).unwrap();
assert_eq!(position(&down), (CmnNominal::B, 0, 3));
// B#4 exists and sounds as C5, an octave *below* the C it spells past.
let bsharp = cmn(CmnNominal::B, 1, 4).transposed(iv(0, 0)).unwrap();
assert_eq!(position(&bsharp), (CmnNominal::B, 1, 4));
}
#[test]
fn every_transposition_is_undone_by_its_inverse() {
let start = cmn(CmnNominal::E, -1, 3);
for interval in [iv(4, 7), iv(-2, -3), iv(7, 12), iv(0, 1), iv(5, 7)] {
let there = start.transposed(interval).unwrap();
let back = there
.transposed(interval.inverse().expect("these inverses exist"))
.unwrap();
assert_eq!(
position(&back),
position(&start),
"{interval:?} did not round-trip"
);
}
}
#[test]
fn a_transposition_refuses_rather_than_saturating() {
// The old operation clamped `alteration` at the i8 bound and reported
// success. An octave past the i8 bound must refuse instead.
let high = cmn(CmnNominal::C, 0, 127);
assert_eq!(
high.transposed(iv(7, 12)),
Err(TransposeRefusal::OutOfRange)
);
let low = cmn(CmnNominal::C, 0, -128);
assert_eq!(
low.transposed(iv(-7, -12)),
Err(TransposeRefusal::OutOfRange)
);
// An alteration that overflows while the octave is fine.
let alt = cmn(CmnNominal::C, 120, 4);
assert_eq!(alt.transposed(iv(0, 20)), Err(TransposeRefusal::OutOfRange));
// Nothing is mutated on refusal — `transposed` is by-value.
assert_eq!(position(&high), (CmnNominal::C, 0, 127));
}
#[test]
fn an_extreme_interval_refuses_instead_of_panicking() {
// The public type admits any `i32`. Every one of these overflowed an
// `i32` intermediate and panicked (or, with overflow-checks off, wrapped
// through unspecified arithmetic) before the widening to `i64`.
let p = cmn(CmnNominal::C, 0, 4);
for (d, c) in [
(i32::MAX, 0),
(i32::MIN, 0),
(0, i32::MAX),
(0, i32::MIN),
(i32::MAX, i32::MAX),
(i32::MIN, i32::MIN),
(i32::MAX, i32::MIN),
] {
assert_eq!(
p.transposed(iv(d, c)),
Err(TransposeRefusal::OutOfRange),
"({d}, {c}) must refuse, not panic"
);
}
// The boundary either side of a representable octave shift.
assert!(cmn(CmnNominal::C, 0, 126).transposed(iv(7, 12)).is_ok());
assert_eq!(
cmn(CmnNominal::C, 0, 127).transposed(iv(7, 12)),
Err(TransposeRefusal::OutOfRange)
);
}
#[test]
fn the_inverse_of_the_unrepresentable_interval_is_none() {
// `-i32::MIN` is not an `i32`. Negating it panicked.
assert_eq!(iv(i32::MIN, 0).inverse(), None);
assert_eq!(iv(0, i32::MIN).inverse(), None);
assert_eq!(iv(i32::MIN, i32::MIN).inverse(), None);
assert_eq!(iv(i32::MIN + 1, 0).inverse(), Some(iv(i32::MAX, 0)));
assert_eq!(iv(4, 7).inverse(), Some(iv(-4, -7)));
}
#[test]
fn a_transposition_refuses_a_non_cmn_position() {
let mut p = cmn(CmnNominal::C, 0, 4);
p.scale_position.position = PitchSpacePosition::Integer {
space_size: 31,
index: 7,
};
assert_eq!(
p.transposed(iv(4, 7)),
Err(TransposeRefusal::NonCmnPosition)
);
p.scale_position.position = PitchSpacePosition::JiVector {
components: vec![1, 0, -1],
};
assert_eq!(
p.transposed(iv(0, 0)),
Err(TransposeRefusal::NonCmnPosition)
);
}
#[test]
fn a_transposition_refuses_a_pitch_pinned_to_a_frequency() {
// AbsoluteHz overrides the tuning system: moving the scale position
// would move the notehead and leave the sound where it was.
let mut p = cmn(CmnNominal::C, 0, 4);
p.acoustic.realization = AcousticRealization::absolute_hz(261.6).unwrap();
assert_eq!(
p.transposed(iv(4, 7)),
Err(TransposeRefusal::AcousticPinned)
);
// A cents offset is relative to whatever the tuning produces for the
// *new* position, so it transposes and survives.
let mut q = cmn(CmnNominal::C, 0, 4);
q.acoustic.realization = AcousticRealization::cents_offset(-13.7).unwrap();
let moved = q.transposed(iv(4, 7)).unwrap();
assert_eq!(position(&moved), (CmnNominal::G, 0, 4));
assert_eq!(moved.acoustic.realization, q.acoustic.realization);
}
#[test]
fn pitch_range_contains_is_advisory_and_frame_aware() {
let range = PitchRange {
lowest: cmn(CmnNominal::C, 0, 2),
highest: cmn(CmnNominal::C, 0, 6),
};
// Interior and inclusive endpoints are in range.
assert_eq!(range.contains(&cmn(CmnNominal::C, 0, 4)), Some(true));
assert_eq!(range.contains(&cmn(CmnNominal::C, 0, 2)), Some(true));
assert_eq!(range.contains(&cmn(CmnNominal::C, 0, 6)), Some(true));
// Below and above are out of range.
assert_eq!(range.contains(&cmn(CmnNominal::C, 0, 1)), Some(false));
assert_eq!(range.contains(&cmn(CmnNominal::C, 0, 7)), Some(false));
// A malformed (reversed) range is *undecidable*, not "everything out of
// range" — it must not reject every comparable pitch.
let reversed = PitchRange {
lowest: cmn(CmnNominal::C, 0, 6),
highest: cmn(CmnNominal::C, 0, 2),
};
assert_eq!(reversed.contains(&cmn(CmnNominal::C, 0, 4)), None);
// A candidate in a different pitch-space frame is undecidable (absolute
// semitones across frames are not comparable).
let other_frame = Pitch {
scale_position: ScalePosition {
space: PitchSpaceId::new("cmn-19"),
position: PitchSpacePosition::Cmn {
nominal: CmnNominal::C,
alteration: 0,
octave: 4,
},
},
acoustic: AcousticPitch {
tuning: TuningReference::Inherit,
realization: AcousticRealization::Implicit,
},
};
assert_eq!(range.contains(&other_frame), None);
}
#[test]
fn enharmonic_equivalence_is_twelve_tet_pitch_class() {
// C-sharp4 and D-flat4 are enharmonic but not structurally equal nor
// scale-position equivalent.
let cis = cmn(CmnNominal::C, 1, 4);
let des = cmn(CmnNominal::D, -1, 4);
assert_ne!(cis, des);
assert!(!cis.scale_position_equivalent(&des));
assert!(cis.enharmonic_equivalent(&des));
// B-sharp 3 wraps up to C4 (same sounding semitone across the octave
// boundary): octave-aware arithmetic handles this.
let bis = cmn(CmnNominal::B, 1, 3);
let c = cmn(CmnNominal::C, 0, 4);
assert!(bis.enharmonic_equivalent(&c));
// A different pitch class is not enharmonic.
assert!(!cmn(CmnNominal::C, 0, 4).enharmonic_equivalent(&cmn(CmnNominal::D, 0, 4)));
// Enharmonic equivalence is a *sounding* notion: the same nominal an
// octave apart is NOT equivalent (it sounds an octave higher).
assert!(!cmn(CmnNominal::C, 0, 4).enharmonic_equivalent(&cmn(CmnNominal::C, 0, 5)));
assert!(cmn(CmnNominal::C, 0, 4).enharmonic_equivalent(&cmn(CmnNominal::C, 0, 4)));
}
#[test]
fn structural_equality_is_not_equivalence() {
let a = cmn(CmnNominal::C, 0, 4);
let b = cmn(CmnNominal::C, 0, 4);
assert_eq!(a, b);
assert!(a.scale_position_equivalent(&b));
}
#[test]
fn enharmonic_requires_the_same_pitch_space() {
// Same 12-TET class but different spaces -> not directly comparable.
let mut other_space = cmn(CmnNominal::C, 1, 4); // C#4
other_space.scale_position.space = PitchSpaceId::new("edo-31");
let cis = cmn(CmnNominal::C, 1, 4);
assert!(cis.enharmonic_equivalent(&cmn(CmnNominal::D, -1, 4))); // same space
assert!(!cis.enharmonic_equivalent(&other_space)); // different space
}
#[test]
fn sounding_equivalence_uses_acoustic_cents_tolerance_class() {
use epiphany_determinism::{Tolerance, ToleranceClass, ToleranceGovernance};
let cents = |c| {
Tolerance::absolute(
ToleranceClass::AcousticCents,
c,
ToleranceGovernance::Validation,
)
.unwrap()
};
let a = cmn(CmnNominal::A, 0, 4);
let b = cmn(CmnNominal::A, 0, 4);
// A resolver placing both at 440 Hz -> equivalent; 440 vs 466 (~100c)
// is not within a 5-cent tolerance.
assert!(a.sounding_equivalent(&b, cents(5.0), |_| Some(440.0)));
let resolve = |p: &Pitch| match &p.scale_position.position {
PitchSpacePosition::Cmn { nominal, .. } if *nominal == CmnNominal::A => Some(440.0),
_ => Some(466.16),
};
assert!(!a.sounding_equivalent(&cmn(CmnNominal::B, -1, 4), cents(5.0), resolve));
// An AbsoluteHz pitch resolves without the closure.
let mut abs = cmn(CmnNominal::A, 0, 4);
abs.acoustic.realization = AcousticRealization::absolute_hz(440.0).unwrap();
assert!(abs.sounding_equivalent(&b, cents(1.0), |_| Some(440.0)));
// A tolerance of the wrong class is a category error and never matches,
// even for identical pitches.
let wrong = Tolerance::absolute(
ToleranceClass::LayoutCoordinate,
5.0,
ToleranceGovernance::Validation,
)
.unwrap();
assert!(!a.sounding_equivalent(&b, wrong, |_| Some(440.0)));
// A resolver returning an infinite frequency never spuriously matches
// (the named tolerance rejects non-finite operands).
assert!(!a.sounding_equivalent(&b, cents(5.0), |_| Some(f64::INFINITY)));
}
#[test]
fn catalog_ids_normalize_to_nfc() {
// Precomposed "é" (U+00E9) vs decomposed "e" + combining acute (U+0301)
// are canonically equivalent and MUST intern equal (Appendix D).
let precomposed = PitchSpaceId::new("caf\u{00e9}");
let decomposed = PitchSpaceId::new("cafe\u{0301}");
assert_eq!(precomposed, decomposed);
assert_eq!(precomposed.as_str(), decomposed.as_str());
use std::collections::hash_map::DefaultHasher;
use std::hash::{Hash, Hasher};
let h = |x: &PitchSpaceId| {
let mut s = DefaultHasher::new();
x.hash(&mut s);
s.finish()
};
assert_eq!(h(&precomposed), h(&decomposed));
}
#[test]
fn system_pitch_derivation_is_deterministic_and_content_addressed() {
let p = cmn(CmnNominal::C, 0, 4);
let id = derive_system_pitch_id(&p);
// Deterministic and in the reserved namespace.
assert_eq!(id, derive_system_pitch_id(&p));
assert_eq!(id.replica(), crate::ids::ReplicaId::SYSTEM_DERIVED);
// Different content derives a different id.
assert_ne!(id, derive_system_pitch_id(&cmn(CmnNominal::D, 0, 4)));
}
#[test]
fn system_pitch_id_byte_form_is_locked() {
// Golden: locks the MUSCSPCH canonical-input layout (space name, scale
// position discriminant + payload, tuning, acoustic realization; strings
// length-prefixed NFC) and the hash. RATIFIED by Pass 11 (item 1.3,
// P11-6): this is the spec's golden, normative in core_spec
// §"System-Derived Pitch Identity",
// Requirement `req:graph:system-derived-pitch-id` — note the tuning
// reference (incl. the Inherit marker) is always part of intrinsic
// identity. A change to the byte form breaks this deliberately.
let id = derive_system_pitch_id(&cmn(CmnNominal::C, 0, 4));
assert_eq!(id.replica(), crate::ids::ReplicaId::SYSTEM_DERIVED);
const GOLDEN: [u8; 16] = [
255, 255, 255, 255, 255, 255, 255, 255, 164, 31, 138, 24, 68, 38, 241, 168,
];
assert_eq!(id.canonical_bytes(), GOLDEN);
}
#[test]
fn reference_pitch_rejects_non_positive_frequency() {
let pos = PitchSpacePosition::Cmn {
nominal: CmnNominal::A,
alteration: 0,
octave: 4,
};
assert!(ReferencePitch::new(pos.clone(), -440.0).is_none());
assert!(ReferencePitch::new(pos.clone(), 0.0).is_none());
assert_eq!(
ReferencePitch::new(pos, 440.0).unwrap().frequency_hz(),
440.0
);
assert_eq!(ReferencePitch::a440().frequency_hz(), 440.0);
}
#[test]
fn acoustic_realization_rejects_bad_floats() {
assert!(AcousticRealization::cents_offset(f64::NAN).is_none());
assert!(AcousticRealization::absolute_hz(0.0).is_none());
assert!(AcousticRealization::absolute_hz(-440.0).is_none());
assert!(AcousticRealization::absolute_hz(440.0).is_some());
}
#[test]
fn accidental_stack_rejects_repeats() {
let mut s = PitchSpelling::cmn(CmnNominal::F, 4);
s.accidentals = vec![AccidentalId::new("sharp")];
assert!(s.accidental_stack_is_well_formed());
s.accidentals = vec![AccidentalId::new("sharp"), AccidentalId::new("sharp")];
assert!(!s.accidental_stack_is_well_formed());
}
#[test]
fn spelling_precedence_default_and_totality() {
let p = SpellingPrecedence::default();
assert!(p.rank(SpellingSourceKind::UserChosen) < p.rank(SpellingSourceKind::Inferred));
assert!(p.rank(SpellingSourceKind::Imported) < p.rank(SpellingSourceKind::Propagated));
// Non-total configurations are rejected.
assert!(SpellingPrecedence::new(vec![SpellingSourceKind::UserChosen]).is_none());
assert!(SpellingPrecedence::new(vec![
SpellingSourceKind::UserChosen,
SpellingSourceKind::UserChosen,
SpellingSourceKind::Imported,
SpellingSourceKind::Propagated,
SpellingSourceKind::Inferred,
])
.is_none());
}
#[test]
fn explicit_spelling_requires_pitch_scope() {
let pid = PitchId::new(crate::ReplicaId(1), 0);
let ok = SpellingAttachment {
scope: SpellingScope::Pitch(pid),
directive: SpellingDirective::Explicit(PitchSpelling::cmn(CmnNominal::C, 4)),
source: SpellingSource::UserChosen,
priority: 0,
layer: None,
};
assert!(ok.is_well_formed());
}
#[test]
fn spell_preserves_authored_cmn_letter() {
// An authored C-sharp keeps its letter (spelling follows the scale
// position, not the trivial old C-default stub).
let p = Pitch {
scale_position: ScalePosition {
space: PitchSpaceId::new("cmn-12"),
position: PitchSpacePosition::Cmn {
nominal: CmnNominal::C,
alteration: 1,
octave: 5,
},
},
acoustic: AcousticPitch {
tuning: TuningReference::Inherit,
realization: AcousticRealization::Implicit,
},
};
let s = spell(&p, &SpellingContext::default());
assert_eq!(s.nominal, SpellingNominal::Cmn(CmnNominal::C));
assert_eq!(s.accidentals, vec![AccidentalId::new("sharp")]);
assert_eq!(s.octave, 5);
assert_eq!(SpellingAlgorithmId::default_id().as_str(), "default");
}
#[test]
fn spell_chromatic_integer_pitch_is_nontrivial() {
// A 12-EDO integer position (chromatic input) gets a real spelling of
// its pitch class, not the old constant middle-C.
let p = Pitch {
scale_position: ScalePosition {
space: PitchSpaceId::new("cmn-12"),
position: PitchSpacePosition::Integer {
space_size: 12,
index: 54, // pitch class 6 (F#/Gb)
},
},
acoustic: AcousticPitch {
tuning: TuningReference::Inherit,
realization: AcousticRealization::Implicit,
},
};
let s = spell(&p, &SpellingContext::default());
// Simplest single-accidental spelling of pitch class 6 (either F# or Gb);
// it is a real, non-default spelling.
assert!(matches!(
s.nominal,
SpellingNominal::Cmn(CmnNominal::F) | SpellingNominal::Cmn(CmnNominal::G)
));
assert_eq!(s.accidentals.len(), 1);
}
}