def to_roman(self, chord, scale_key):
"""Converts a `Chord` to `Roman`.
Creates the `Roman` based on the `Chord` and a `Scale` or `Key`.
Parameters
----------
chord : Chord
The `Chord` to be converted.
scale_key : Scale or Key
The `Scale` or `Key` to base the `Roman` on.
Returns
-------
Roman
The `Roman` of the `Chord`.
Warns
-----
UserWarning
If the `Chord` is a power or sus chord.
Examples
--------
>>> KE = KeyEditor()
>>> SE = ScaleEditor()
>>> CE = ChordEditor()
>>> CRC = ChordRomanConverter()
>>> c_key = KE.create_key("C")
>>> c_scale = SE.create_scale(c_key)
>>> d = CE.create_diatonic(c_scale, 2)
>>> CRC.to_roman(d, c_key)
ii roman chord
>>> f = CE.create_diatonic(c_scale, 4)
>>> CRC.to_roman(f, c_scale)
IV roman chord
"""
if chord.quality.value in {"power", "sus2", "sus4"}:
warnings.warn(
"Warning: Power and sus chords are defaulted to major chords",
UserWarning)
chord = self._CE.change_chord(chord, quality="Maj", inplace=False)
if isinstance(scale_key, Scale):
scale_root = scale_key.key.root
else:
scale_root = scale_key.root
scale = self._SE.create_scale(scale_root, "major")
root = self._get_roman_root(chord, scale)
quality = self._get_roman_quality(chord)
inversion = self._get_roman_inversion(chord)
return Roman(root, quality, inversion)
def test_notation():
r = Roman("I", "M+", (6, 4))
assert "IM+64" == str(r)
def test_equality_not_implemented():
r = Roman("I", "", ())
assert r != len
def test_equality_2():
r = Roman("IV", "+", (6, ))
assert "IV+6" == r
def test_equality():
r = Roman("I", "+", (6, ))
o = Roman("I", "+", (6, ))
assert r == o
def test_repr():
r = Roman("IV", "+", (6, ))
assert "IV+6 roman chord" == repr(r)
def test_notation_3():
r = Roman("IV", "+", (6, ))
assert "IV+6" == str(r)
def test_notation_2():
r = Roman("v", "\u00B0", ())
assert "v\u00B0" == str(r)