theory

Documentation

Overview

Primitive and high level music theory concepts to manipulate notes, chords, rhythms, etc.

Index

• Constants
• Variables
• func ChordOnNoteInt(note int, chord string) []int
• func EuclidianRhythm(n, over int) []bool
• func InvertChord(chord []int, inversions int) []int
• func NoteNameToString(n NoteName) string
• func ScaleOnNoteInt(note int, scale string) []int
• type Note
  • func MustNoteFromString(s string) *Note
  • func NoteFromInt(n int) *Note
  • func NoteFromString(s string) (*Note, error)
  • func (n *Note) Augment()
  • func (n *Note) Chord(chord string) Notes
  • func (n *Note) Diminish()
  • func (n *Note) Int() int
  • func (n *Note) Pitch() float64
  • func (n *Note) String() string
• type NoteName
  • func MustNewNoteNameFromString(s string) NoteName
  • func NewNoteNameFromString(s string) (NoteName, error)
• type Notes
  • func ChordOnNote(note *Note, chord string) Notes
  • func MustNotesFromString(s string) Notes
  • func NotesFromString(s string) (Notes, error)
  • func (n Notes) Augment()
  • func (n Notes) Diminish()
• type Scale
  • func NewScale(ascending, descending Notes) *Scale
  • func (s *Scale) GetAscendingIntervals() []int

Constants

const (
	C1  = 24
	C2  = 36
	C3  = 48
	C4  = 60
	Db4 = 61
	D4  = 62
	E4  = 64
	F4  = 65
	G4  = 67
	A4  = 69
	B4  = 71
	C5  = 72
	C6  = 84
	C7  = 96
	A7  = 105
)

Variables

var Aeolian = NewScale(
	MustNotesFromString("A B C D E F G"),
	MustNotesFromString("G F E D C B A"),
)

var Chords = map[string][]int{
	"m":   []int{3, 4, 5},
	"M":   []int{4, 3, 5},
	"m7":  []int{3, 4, 3, 2},
	"m67": []int{3, 4, 1, 2, 2},
	"M7":  []int{4, 3, 4, 1},
	"7":   []int{4, 3, 3, 2},
}

var Diatonic = Ionian

var Dorian = NewScale(
	MustNotesFromString("D E F G A B C"),
	MustNotesFromString("C B A G F E D"),
)

var HarmonicMajor = NewScale(
	MustNotesFromString("C D E F G Ab B"),
	MustNotesFromString("B Ab G F E D C"),
)

var Ionian = NewScale(
	MustNotesFromString("C D E F G A B"),
	MustNotesFromString("B A G F E D C"),
)

var Locrian = NewScale(
	MustNotesFromString("B C D E F G A"),
	MustNotesFromString("A G F E D C B"),
)

var Lydian = NewScale(
	MustNotesFromString("F G A B C D E"),
	MustNotesFromString("C B A G F E D"),
)

var MajorScale = Ionian

var Mixolydian = NewScale(
	MustNotesFromString("G A B C D E F"),
	MustNotesFromString("B A G F E D C"),
)

var NoteNames = []NoteName{C, D, E, F, G, A, B}

var NoteToPitch = make([]float64, 128)

var Phrygian = NewScale(
	MustNotesFromString("E F G A B C D"),
	MustNotesFromString("D C B A G F E"),
)

var Scales = map[string]*Scale{
	"diatonic":       Diatonic,
	"ionian":         Ionian,
	"dorian":         Dorian,
	"phrygian":       Phrygian,
	"lydian":         Lydian,
	"mixolydian":     Mixolydian,
	"aeolian":        Aeolian,
	"locrian":        Locrian,
	"harmonic major": HarmonicMajor,
}

Functions

func ChordOnNoteInt

func ChordOnNoteInt(note int, chord string) []int

func EuclidianRhythm

func EuclidianRhythm(n, over int) []bool

func InvertChord

func InvertChord(chord []int, inversions int) []int

func NoteNameToString

func NoteNameToString(n NoteName) string

func ScaleOnNoteInt

func ScaleOnNoteInt(note int, scale string) []int

Types

type Note

type Note struct {
	Name        NoteName
	Accidentals int
	Octave      int
}

func MustNoteFromString

func MustNoteFromString(s string) *Note

func NoteFromInt

func NoteFromInt(n int) *Note

func NoteFromString

func NoteFromString(s string) (*Note, error)

func (*Note) Augment

func (n *Note) Augment()

func (*Note) Chord

func (n *Note) Chord(chord string) Notes

func (*Note) Diminish

func (n *Note) Diminish()

func (*Note) Int

func (n *Note) Int() int

func (*Note) Pitch

func (n *Note) Pitch() float64

func (*Note) String

func (n *Note) String() string

type NoteName

type NoteName = int

const (
	C NoteName = 0
	D NoteName = 2
	E NoteName = 4
	F NoteName = 5
	G NoteName = 7
	A NoteName = 9
	B NoteName = 11
)

func MustNewNoteNameFromString

func MustNewNoteNameFromString(s string) NoteName

func NewNoteNameFromString

func NewNoteNameFromString(s string) (NoteName, error)

type Notes

type Notes []*Note

func ChordOnNote

func ChordOnNote(note *Note, chord string) Notes

func MustNotesFromString

func MustNotesFromString(s string) Notes

func NotesFromString

func NotesFromString(s string) (Notes, error)

func (Notes) Augment

func (n Notes) Augment()

func (Notes) Diminish

func (n Notes) Diminish()

type Scale

type Scale struct {
	Ascending  Notes
	Descending Notes
}

func NewScale

func NewScale(ascending, descending Notes) *Scale

The ascending and descending notes should be supplied in the key of C. If descending is nil then it will default to the reverse of ascending.

func (*Scale) GetAscendingIntervals

func (s *Scale) GetAscendingIntervals() []int