Type Alias ChordToRomanOptions

Render a tonicizing chord as an applied numeral (V7/V, viio7/ii) instead of naming its root against the home key (II7, #ivo7).

Off by default: naming the root is always a correct spelling, whereas whether a chromatic dominant is genuinely applied is a reading only the caller can make. Turning it on names the chords secondaryDominant builds as the applied numerals they are, except in three cases, where the numeral names the root against the home key as it does with this off:

• The target degree carries no perfect fifth: nothing tonicizes a diminished triad, so a chord over the seventh degree of a major key stays #IV7 rather than becoming a numeral no harmony text writes.
• The target is the tonic, which its own dominant points at: V7 is the key's dominant and V/I is a numeral no harmony text writes either.
• The chord is diatonic to the key, which keeps the function of its degree rather than tonicizing another. G7 is VII7 in A minor and I7 in C mixolydian, not V7/III and V7/IV.

Render a first-inversion Neapolitan under its figured name N6 instead of the numeral bII6.

Off by default, for the opposite reason to applied: both spellings name the same chord and bII6 is already correct, so which one to write is a house-style choice rather than an analysis. romanToChord accepts either whatever this is set to. The augmented sixths need no such switch — no numeral spells them at all, so they always render as It6, Fr6 and Ger6.