Chord degree, 1-based; 8 is the octave above the root.
Optionalalter?: numberChromatic alteration in semitones, for a flattened or raised degree.
OptionallengthSteps?: numberSounding length in sixteenths. Absent, the note sounds to the next onset, as a line written by generateBassLine does: the built-in figures name no length, so a figure is legato unless it says otherwise.
Optionalarticulation?: ArticulationHow the note is played, when it is more than a plain note.
One note of a lick, relative to the chord it is played over.
A degree is 1-based and counts up from the chord's root: 1 is the root, 3 the third, 8 the octave. Degrees the chord itself names — the third, fifth and seventh — are taken from the chord, so the same figure comes out major over a major chord and minor over a minor one. A degree the chord's quality settles without stating it follows the quality: the third of a suspended chord is the tone the suspension put there, and a seventh chord's remaining degrees are its own chord scale's. Only what the harmony leaves open is taken from the key. That is what lets a figure be written once and fit a whole progression.