pub fn split_secondary(figure: &str) -> (&str, Option<String>)Expand description
Where music21 splits a secondary numeral off a figure.
Its own regular expression asks for a letter after the slash, and
deliberately not o — so vii/o7 is a half-diminished seventh and not a
numeral applied to some chord o7 — and not a digit, so the 6/5 of
Ger6/5 stays one figure.