theory

Documentation

Overview

Package theory implements music theory. There is also support for associating MIDI numbers with music theory. It vaguely corresponds to the MusicXML data structures.

Note that this is inahga's(tm) music theory. My understanding of actual music theory is pretty bad :).

Index

• type Accidental
  • func (a Accidental) String() string
• type Class
  • func (c Class) String() string
• type Clef
  • func (c Clef) String() string
• type Duration
• type Key
  • func GetKeyByClass(class Class, adjustment Accidental, mode Mode) (Key, error)
  • func MustGetKeyByClass(class Class, adjustment Accidental, mode Mode) Key
• type KeySignature
  • func (s KeySignature) BassNote() Note
  • func (s KeySignature) TrebleNote() Note
• type Measure
• type Mode
  • func (m Mode) String() string
• type Note
  • func N(c Class, a Accidental, o Octave, d Duration) Note
• type Octave
• type Part
• type Time
• type Tone
  • func (t Tone) String() string

Types

type Accidental

type Accidental int

const (
	Natural Accidental = iota
	Flat
	Sharp
)

func (Accidental) String

func (a Accidental) String() string

type Class

type Class int

const (
	C Class = iota
	D
	E
	F
	G
	A
	B
)

func (Class) String

func (c Class) String() string

type Clef

type Clef int

const (
	Treble Clef = iota
	Bass
)

func (Clef) String

func (c Clef) String() string

type Duration

type Duration float64

const (
	Whole Duration = 1 << iota
	Half
	Quarter
	Eight
	Sixteenth
	ThirtySecond
)

type Key

type Key struct {
	Major Tone
	Minor Tone
	Sig   []KeySignature
}

func GetKeyByClass

func GetKeyByClass(class Class, adjustment Accidental, mode Mode) (Key, error)

func MustGetKeyByClass

func MustGetKeyByClass(class Class, adjustment Accidental, mode Mode) Key

type KeySignature

type KeySignature struct {
	Tone
	TrebleOctave Octave // Helps render the time signature for treble clef
	BassOctave   Octave // Helps render the time signature for bass clef
}

func (KeySignature) BassNote

func (s KeySignature) BassNote() Note

BassNote returns a note indicating the octave at which the signature should be placed when rendering bass clef.

func (KeySignature) TrebleNote

func (s KeySignature) TrebleNote() Note

BassNote returns a note indicating the octave at which the signature should be placed when rendering treble clef.

type Measure

type Measure []Note

type Mode

type Mode int

const (
	Major Mode = iota
	Minor
)

func (Mode) String

func (m Mode) String() string

type Note

type Note struct {
	Tone
	Octave
	Duration
}

Note represents the pitch and duration of a sound.

func N

func N(c Class, a Accidental, o Octave, d Duration) Note

type Octave

type Octave int

type Part

type Part struct {
	Clef
	Time
	Key
	Measures []Measure
}

type Time

type Time struct {
	BeatsPerBar, BeatUnit int
}

type Tone

type Tone struct {
	Class
	Accidental
}

func (Tone) String

func (t Tone) String() string