Structures

The Mode type is used for defining custom scale structures. Initialized with either a name string and an array of Int offsets-from-tonic, or with a name string and a pitch-class set (in which case the prime form is used).

The Pitch type represents both a pitch class and an octave. It also contains a MIDI note number representation. Absolute pitch parity can be checked with ==, pitch class parity can be checked with ~=.

The Note abstraction contains a Pitch instance, a Duration instance, and a velocity.

The NoteSequence abstraction represents an ordered collection of Note objects.

The ToneRow type deals with ordered collections of pitch-classes and adds utility methods for working with tone rows in compositional contexts.

The PCSet type deals with collections of pitch-classes. It abstracts an Array of pitch-classes than a set type, in order to allow for duplicates, explicit ordering, etc.

The ToneMatrix type deals with tone matrices expressed as multidimensional arrays, or arrays of ToneRow instances.

The Chord type provides an abstraction for dealing with vertically-oriented harmonic structures. Can be initialized with a pitch-class set, with a chord symbol (e.g. Chord(Fmaj7#11)), or with MIDI note numbers as an Int array. Chord parity, considering inversional equivalence, can be checked using the == operator.

The SeparatedChordSymbol type provides a separated root and symbol suffix, as an intermediary stage in the chord-parsing process.

The TimeSignature type consists of a numerator and a denominator, together representing a time signature. It currently only supports dyadic rationals, but support for ‘irrational’ time signatures is planned.

The Tempo type consists of a beats-per-minute value, and a NoteValue instance to indicate what each of these beats is. It can be initialized with a BPM value alone, in which case the beat’s value defaults to a quarter note, or with both together. Additionally, it can be initialized with a description, e.g. Tempo(Andante). There is an internal soft limit that defaults to 400.0 and can be user-modified.

The RomanNumeral type abstracts data and operations related to working with roman-numeral expressions of harmony. Two basic systems of roman-numerals are provided: ‘Traditional’ and ‘Berklee’, the former employing figured-bass notation and both upper and lower case characters, and the latter resembling chord symbols and using all upper case characters.