code: Rule Mode() {
  		return FirstOf(Major(), Lydian(), Ionian(), Mixolydian(),
  				Dorian(), Aeolian(), Phrygian(), Locrian(),
  				Explicit(), Minor()
  			).label(Mode);
  	}
docs: mode ::= minor / major / lydian / ionian / mixolydian / dorian / aeolian / phrygian / locrian