Chords and Harmony

Flow has built-in support for chord literals, chord analysis functions, roman numeral resolution, arpeggios, scale operations, and voice-led chord progressions.

Chord Literals

Chords are created using standard chord symbol notation:

Chord c1 = Cmaj      Note: C major
Chord c2 = Dm        Note: D minor
Chord c3 = Gdom7     Note: G dominant 7th
Chord c4 = Cmaj7     Note: C major 7th
Chord c5 = Am7       Note: A minor 7th
Chord c6 = Bdim      Note: B diminished
Chord c7 = Caug      Note: C augmented
Chord c8 = Dsus2     Note: D sus2
Chord c9 = Asus4     Note: A sus4

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Chord Qualities

Suffix	Quality	Intervals
`maj`	Major	1-3-5
`m` / `min`	Minor	1-b3-5
`dim`	Diminished	1-b3-b5
`aug`	Augmented	1-3-#5
`7` / `dom7`	Dominant 7th	1-3-5-b7
`maj7`	Major 7th	1-3-5-7
`m7` / `min7`	Minor 7th	1-b3-5-b7
`dim7`	Diminished 7th	1-b3-b5-bb7
`m7f5`	Half-diminished (m7♭5)	1-b3-b5-b7
`sus2`	Suspended 2nd	1-2-5
`sus4`	Suspended 4th	1-4-5
`add9`	Add 9th	1-3-5-9
`9`	Dominant 9th	1-3-5-b7-9
`6`	Major 6th	1-3-5-6
`m6`	Minor 6th	1-b3-5-6

Sharp and Flat Notation in Chord Symbols

Chord roots use s for sharp and f for flat:

Chord cs = Csmaj     Note: C# major
Chord bf = Bfm       Note: Bb minor
Chord fs = Fsmaj7    Note: F# major 7th

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This is different from note literal accidentals, which use + and - (e.g., C4+ = C# at octave 4). See Note Streams.

G7 is parsed as the note G at octave 7 in all contexts — including inside note streams. Use Gdom7 for the dominant 7th chord.

Chord Functions

use "@std"

Chord c = Cmaj7

String root = (chordRoot c)                 Note: "C"
String quality = (chordQuality c)           Note: "maj7"
String[] notes = (chordNotes c)             Note: ["C4", "E4", "G4", "B4"]
(print $"root: {root}, quality: {quality}, count: {notes -> len}")

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Chords in Note Streams

Chord symbols can be used directly in note streams. Each chord expands to its component notes played simultaneously, with auto-fit duration:

timesig 4/4 {
    Sequence prog = | Cmaj7 Am7 Dm7 G7 |
    (print (str prog))
}

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Append duration suffixes (and dots) to a named chord element to control its rhythm. A chord with a letter-bearing quality (maj7, m7, dim7, sus4, m, …) fuses directly with the duration letter — Cmaj7q — just like a note literal. The space-separated form also works and is required for chords whose quality is a bare digit (Gdom7, C6):

timesig 4/4 {
    Note: fused — letter-quality chord + duration
    Sequence fused = | Cmaj7q Am7q Dm7h Fsmaj7h |

    Note: space-separated — works for any chord, required for bare-digit qualities
    Sequence spaced = | Cmaj7 q Am7 q Gdom7 h Dsus4 h |
}

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Bare-digit chords don’t fuse. G7, Bb7, and C6 parse as a note + octave (so Bb7q is the note Bb7 as a quarter, not the Bb dominant 7th — see the warning at the top of this page). When you mean the chord, use a letter-quality spelling (Gdom7, Bfdom7) so it fuses, or write the dominant explicitly.

Roman Numerals

Within a key context, roman numerals represent scale-degree chords:

key Cmajor {
    timesig 4/4 {
        Note: in C major: I=C, IV=F, V=G
        Sequence mjr = | I IV V I |

        Note: lowercase = minor: ii=Dm, vi=Am
        Sequence mix = | ii V7 I |
    }
}

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Roman Numeral Reference

Numeral	Degree	Default Quality
`I` / `i`	1st (tonic)	Major / minor
`II` / `ii`	2nd (supertonic)	Major / minor
`III` / `iii`	3rd (mediant)	Major / minor
`IV` / `iv`	4th (subdominant)	Major / minor
`V` / `v`	5th (dominant)	Major / minor
`VI` / `vi`	6th (submediant)	Major / minor
`VII` / `vii`	7th (leading)	Major / minor

Uppercase = major, lowercase = minor. Extensions like V7 add a dominant 7th.

Resolving Numerals Programmatically

use "@std"

Chord v = (resolveNumeral "V" "Cmajor")
(print (str v))      Note: G major

Chord v7 = (resolveNumeral "V7" "Cmajor")
(print (str v7))     Note: G dominant 7th

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Chord Progressions with Voice Leading

For smoother voice leading between chords, use the dedicated progression expression:

use "@std"

key Cmajor {
    Sequence chords = progression | I IV V I |
    Sequence thick  = progression voices 4 | I:2 IV vi V:2 |
}

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See Chord Progressions for the full reference, including bar-count suffixes, voice counts, and voice-leading behavior.

Arpeggios

Generate arpeggiated sequences from chords. The 2-arg form takes a direction string and emits eighth notes:

use "@std"

Sequence up     = (arpeggio Cmaj "up")
Sequence down   = (arpeggio Cmaj "down")
Sequence updown = (arpeggio Cmaj "updown")

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The 4-arg form gives full control over rate, direction, and pattern. Rate is a NoteValue constant from @notation (QUARTER, EIGHTH, SIXTEENTH, etc.) — bare q/e/s are only valid as duration suffixes inside note streams:

use "@std"
use "@notation"

Note: direction is up/down/updown/downup/random; pattern is linear/chord-tone/scale-tone
Sequence triplets = (arpeggio Cmaj7 QUARTER "updown" "linear")
Sequence rolling  = (arpeggio Cmaj7 SIXTEENTH "down" "linear")

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downup and random are accepted today; chord-tone and scale-tone currently behave the same as linear (placeholders for future expansion).

Chord Inversions and Voicings

Invert a chord by rotating its lowest N notes up an octave each:

use "@std"

Chord triad = Cmaj                          Note: C4 E4 G4
Chord first = (inversion triad 1)           Note: E4 G4 C5
Chord second = (inversion triad 2)          Note: G4 C5 E5

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Apply a named voicing for richer textures (jazz comping, open spacing, etc.):

use "@std"

Chord shell = Cmaj7

Chord drop2  = (voicing shell "drop2")      Note: lower the 2nd-from-top note an octave
Chord drop3  = (voicing shell "drop3")      Note: lower the 3rd-from-top note an octave
Chord open   = (voicing shell "open")       Note: raise the middle note an octave (wider)
Chord close  = (voicing shell "close")      Note: collapse to within one octave of root
Chord spread = (voicing shell "spread")     Note: raise the highest note another octave

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Voicings whose minimum-note requirement isn’t met (drop2/drop3 need ≥4 notes; spread/open/close need ≥3) return the input unchanged — no error, no warning. Same for out-of-range inversion indices.

Scale Operations

Get the note names of any scale:

use "@std"

String[] cMajor = (scaleNotes "Cmajor")      Note: 7 notes
String[] aMinor = (scaleNotes "Aminor")      Note: 7 notes
(print (str cMajor))

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Scales are useful for constraining diatonic mutation with vary:

Note: snippet - not standalone; mel must be defined first, e.g.: Sequence mel = | C4 D4 E4 F4 G4 |
Sequence varied = (vary mel 0.3 "pitch" "Cmajor")

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See Generative Music.

Chord Bracket Notation (Custom Voicings)

For custom voicings not limited to standard shapes, use bracket notation in a note stream:

timesig 4/4 {
    Sequence custom = | [C4 E4 G4]q [D4 F4 A4]q [E4 G4 B4]q [C4 E4 G4]q |
}

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Section Query Functions

use "@std"

section intro { Sequence mel = | C4 E4 G4 C5 | }
section verse { Sequence mel = | E4 F4 G4 A4 | }

Song mySong = [intro verse]

String[] sections = (getSections mySong)
(print (str sections))               Note: ["intro", "verse"]

Note: sectionSequences(Song, String) returns the sequence names of one named section.
String[] introSeqs = (sectionSequences mySong "intro")
(print (str introSeqs))              Note: ["mel"]

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Chords and Harmony

Chord Literals

Chord Qualities

Sharp and Flat Notation in Chord Symbols

Chord Functions

Chords in Note Streams

Roman Numerals

Roman Numeral Reference

Resolving Numerals Programmatically

Chord Progressions with Voice Leading

Arpeggios

Chord Inversions and Voicings

Scale Operations

Chord Bracket Notation (Custom Voicings)

Section Query Functions

See Also