# ------------------------------------------------------------------------------
# Name: harmony.py
# Purpose: music21 classes for representing harmonies and chord symbols
#
# Authors: Michael Scott Asato Cuthbert
# Beth Hadley
# Jacob Tyler Walls
# Christopher Ariza
#
# Copyright: Copyright © 2011-2024 Michael Scott Asato Cuthbert
# License: BSD, see license.txt
# ------------------------------------------------------------------------------
'''
An object representation of harmony, a subclass of chord, as encountered as chord symbols or
roman numerals, or other chord representations with a defined root.
'''
from __future__ import annotations
import collections
import copy
import re
import unittest
import typing as t
from music21 import base
from music21 import chord
from music21 import common
from music21 import duration
from music21 import environment
from music21 import exceptions21
from music21 import interval
from music21 import key
from music21 import pitch
from music21 import prebase
from music21 import style
environLocal = environment.Environment('harmony')
if t.TYPE_CHECKING:
from music21.figuredBass import realizerScale
# --------------------------------------------------------------------------
# Y indicates this chord_type is an official XML chord type
# N indicates XML does not support this chord type
# Y : 'some string' indicates XML supports the chord type, but
# uses a name different from what I use in this dictionary
# I mostly used XML's nomenclature, but for a few of the sevenths
# I just couldn't stand to adopt their names because they aren't consistent
# sorry, you can't use '-' for minor, cause that's a flat in music21
# noinspection SpellCheckingInspection
CHORD_TYPES = collections.OrderedDict([
('major', ['1,3,5', ['', 'M', 'maj']]), # Y
('minor', ['1,-3,5', ['m', 'min']]), # Y
('augmented', ['1,3,#5', ['+', 'aug']]), # Y
('diminished', ['1,-3,-5', ['dim', 'o']]), # Y
# sevenths
('dominant-seventh', ['1,3,5,-7', ['7', 'dom7', ]]), # Y: 'dominant'
('major-seventh', ['1,3,5,7', ['maj7', 'M7']]), # Y
('minor-major-seventh', ['1,-3,5,7', ['mM7', 'm#7', 'minmaj7']]), # Y: 'major-minor'
('minor-seventh', ['1,-3,5,-7', ['m7', 'min7']]), # Y
('augmented-major-seventh', ['1,3,#5,7', ['+M7', 'augmaj7']]), # N
('augmented-seventh', ['1,3,#5,-7', ['7+', '+7', 'aug7']]), # Y
('half-diminished-seventh', ['1,-3,-5,-7', ['ø7', 'm7b5']]), # Y: 'half-diminished'
('diminished-seventh', ['1,-3,-5,--7', ['o7', 'dim7']]), # Y
('seventh-flat-five', ['1,3,-5,-7', ['dom7dim5']]), # N
# sixths
('major-sixth', ['1,3,5,6', ['6']]), # Y
('minor-sixth', ['1,-3,5,6', ['m6', 'min6']]), # Y
# ninths
('major-ninth', ['1,3,5,7,9', ['M9', 'Maj9']]), # Y
('dominant-ninth', ['1,3,5,-7,9', ['9', 'dom9']]), # Y
('minor-major-ninth', ['1,-3,5,7,9', ['mM9', 'minmaj9']]), # N
('minor-ninth', ['1,-3,5,-7,9', ['m9', 'min9']]), # N
('augmented-major-ninth', ['1,3,#5,7,9', ['+M9', 'augmaj9']]), # Y
('augmented-dominant-ninth', ['1,3,#5,-7,9', ['9#5', '+9', 'aug9']]), # N
('half-diminished-ninth', ['1,-3,-5,-7,9', ['ø9']]), # N
('half-diminished-minor-ninth', ['1,-3,-5,-7,-9', ['øb9']]), # N
('diminished-ninth', ['1,-3,-5,--7,9', ['o9', 'dim9']]), # N
('diminished-minor-ninth', ['1,-3,-5,--7,-9', ['ob9', 'dimb9']]), # N
# elevenths
('dominant-11th', ['1,3,5,-7,9,11', ['11', 'dom11']]), # Y
('major-11th', ['1,3,5,7,9,11', ['M11', 'Maj11']]), # Y
('minor-major-11th', ['1,-3,5,7,9,11', ['mM11', 'minmaj11']]), # N
('minor-11th', ['1,-3,5,-7,9,11', ['m11', 'min11']]), # Y
('augmented-major-11th', ['1,3,#5,7,9,11', ['+M11', 'augmaj11']]), # N
('augmented-11th', ['1,3,#5,-7,9,11', ['+11', 'aug11']]), # N
('half-diminished-11th', ['1,-3,-5,-7,9,11', ['ø11']]), # N
('diminished-11th', ['1,-3,-5,--7,9,11', ['o11', 'dim11']]), # N
# thirteenths
('major-13th', ['1,3,5,7,9,11,13', ['M13', 'Maj13']]), # Y
('dominant-13th', ['1,3,5,-7,9,11,13', ['13', 'dom13']]), # Y
('minor-major-13th', ['1,-3,5,7,9,11,13', ['mM13', 'minmaj13']]), # N
('minor-13th', ['1,-3,5,-7,9,11,13', ['m13', 'min13']]), # Y
('augmented-major-13th', ['1,3,#5,7,9,11,13', ['+M13', 'augmaj13']]), # N
('augmented-dominant-13th', ['1,3,#5,-7,9,11,13', ['+13', 'aug13']]), # N
('half-diminished-13th', ['1,-3,-5,-7,9,11,13', ['ø13']]), # N
# other
('suspended-second', ['1,2,5', ['sus2']]), # Y
('suspended-fourth', ['1,4,5', ['sus', 'sus4']]), # Y
('suspended-fourth-seventh', ['1,4,5,-7', ['7sus', '7sus4']]), # Y
('Neapolitan', ['1,-2,3,-5', ['N6']]), # Y
('Italian', ['1,#4,-6', ['It+6', 'It']]), # Y
('French', ['1,2,#4,-6', ['Fr+6', 'Fr']]), # Y
('German', ['1,-3,#4,-6', ['Gr+6', 'Ger']]), # Y
('pedal', ['1', ['pedal']]), # Y
('power', ['1,5', ['power']]), # Y
('Tristan', ['1,#4,#6,#9', ['tristan']]), # Y
])
# these are different names used by MusicXML and others,
# and the authoritative name that they resolve to
CHORD_ALIASES = {'dominant': 'dominant-seventh',
'major-minor': 'minor-major-seventh',
'half-diminished': 'half-diminished-seventh',
}
# ------------------------------------------------------------------------------
class HarmonyException(exceptions21.Music21Exception):
pass
# ------------------------------------------------------------------------------
[docs]
class Harmony(chord.Chord):
'''
Harmony objects in music21 are a special type of chord - they retain all
the same functionality as a chord (and inherit from chord directly),
although they have special representations symbolically. They contain a
figure representation, a shorthand, for the actual pitches they contain.
This shorthand is commonly used on musical scores rather than writing out
the chord pitches. Thus, each harmony object has an attribute,
self.writeAsChord that dictates whether the object will be written to a
score as a chord (with pitches realized) or with just the
figure (as in Chord Symbols).
Most users should start with the ChordSymbol class or the RomanNumeral
class. The Harmony object is primarily a base object for defining other
sorts of objects:
>>> c6 = harmony.ChordSymbol('C/E')
>>> c6
<music21.harmony.ChordSymbol C/E>
By default, Harmony objects just float above the score and are a sort of
analytical object. To make them also count as pitches in a score, use
`writeAsChord=True`
>>> c6.writeAsChord = True
>>> c6
<music21.harmony.ChordSymbol C/E: E G C>
Or individual components can be specified:
>>> c6_again = harmony.ChordSymbol(root='C', bass='E', kind='major')
>>> c6_again
<music21.harmony.ChordSymbol C/E>
It is also possible to instantiate an empty Harmony object and
then set components later, but this is an advanced and delicate operation:
>>> h = harmony.ChordSymbol()
>>> h.root('B-3')
>>> h.bass('D', allow_add=True)
>>> h.inversion(1, transposeOnSet=False)
>>> h.addChordStepModification(harmony.ChordStepModification('add', 4))
>>> h
<music21.harmony.ChordSymbol B-/D add 4>
>>> h = harmony.ChordSymbol('C7/E')
>>> h.root()
<music21.pitch.Pitch C4>
>>> h.bass()
<music21.pitch.Pitch E3>
>>> h.inversion()
1
>>> h.isSeventh()
True
>>> [str(p) for p in h.pitches]
['E3', 'G3', 'B-3', 'C4']
>>> sus = harmony.ChordSymbol('Dsus4')
>>> sus.root()
<music21.pitch.Pitch D3>
Accepts a keyword 'updatePitches'. By default, it
is `True`, but can be set to `False` to initialize faster if pitches are not needed.
The `placement` attribute controls where the symbol appears relative to the staff,
matching the MusicXML `placement` attribute on `<harmony>`. Valid values are
``'above'``, ``'below'``, or ``None`` (let the notation software decide):
>>> cs = harmony.ChordSymbol('G7')
>>> cs.placement is None
True
>>> cs.placement = 'below'
>>> cs.placement
'below'
'''
# sort harmony just before notes and chords and other default objects
classSortOrder = base.Music21Object.classSortOrder - 1
_styleClass = style.TextStyle
# INITIALIZER #
def __init__(self,
figure: str|None = None,
root: str|pitch.Pitch|None = None,
bass: str|pitch.Pitch|None = None,
inversion: int|None = None,
updatePitches: bool = True,
**keywords
):
super().__init__(**keywords)
self._writeAsChord = False
# TODO: Deal with the roman numeral property of harmonies.
# MusicXML documentation is ambiguous:
# A root is a pitch name like C, D, E, where a function is an
# indication like I, II, III. It is an either/or choice to avoid
# data inconsistency.
# a romanNumeral numeral object, musicxml stores this within a node
# called <function> which might conflict with the Harmony
self._roman = None
self.placement: str|None = None
# specify an array of degree alteration objects
self.chordStepModifications: list[ChordStepModification] = []
self._degreesList: list[str] = []
self._key = None
# senseless to parse inversion until chord members are populated
self._updateFromParameters(root=root, bass=bass)
# figure is the string representation of a Harmony object
# for example, for Chord Symbols the figure might be 'Cm7'
# for roman numerals, the figure might be 'I7'
self._figure = figure
if self._figure:
self._parseFigure()
# if the bass is not specified, but the root is,
# assume the bass and root are identical and
# assign the values accordingly
if 'bass' not in self._overrides and 'root' in self._overrides:
self.bass(self._overrides['root'], allow_add=True)
if (updatePitches
and (
self._figure # == '' or is not None
or 'root' in self._overrides
or 'bass' in self._overrides)):
self._updatePitches()
self._updateFromParameters(root=root, bass=bass, inversion=inversion)
# SPECIAL METHODS #
def _reprInternal(self):
summary = self.figure
if self.writeAsChord:
summary += ': '
summary += ' '.join([p.name for p in self.pitches])
return summary
# PROTECTED METHODS #
def _parseFigure(self):
'''
Subclass this in extensions (protected in TypeScript/Java speak).
'''
return
def _updatePitches(self):
'''
Subclass this in extensions (protected in TypeScript/Java speak).
'''
return
def _updateFromParameters(
self,
root: str|pitch.Pitch|None,
bass: str|pitch.Pitch|None,
inversion: int|None = None
) -> None:
'''
This method must be called twice, once before the pitches
are rendered, and once after. This is because after the pitches
are rendered, the root() and bass() become reset by the chord class,
but we want the objects to retain their initial root, bass, and inversion.
'''
if root and isinstance(root, str):
root_str = common.cleanedFlatNotation(root)
self.root(pitch.Pitch(root_str, octave=3))
elif root is not None:
self.root(root)
# set inversion first...
if inversion is not None:
self.inversion(inversion, transposeOnSet=True)
# and then bass.
if bass and isinstance(bass, str):
bass_str = common.cleanedFlatNotation(bass)
self.bass(pitch.Pitch(bass_str, octave=3), allow_add=True)
elif bass is not None:
self.bass(bass, allow_add=True)
# PUBLIC PROPERTIES #
@property
def figure(self):
'''
Get or set the figure of the harmony object. The figure is the
character (string) representation of the object. For example, 'I',
'CM', '3#'.
When you instantiate a harmony object, if you pass in a figure it
is stored internally and returned when you access the figure
property. If you don't instantiate the object with a figure, this
property calls :meth:`music21.harmony.Harmony.findFigure` method which
deduces the figure provided other information about the object,
especially the chord.
If the pitches of the harmony object have been modified after being
instantiated, call :meth:`music21.harmony.Harmony.findFigure` to deduce the
new figure.
>>> h = harmony.ChordSymbol('CM')
>>> h.figure
'CM'
>>> harmony.ChordSymbol(root='C', bass='A', kind='minor').figure
'Cm/A'
>>> h.bass(note.Note('E'))
>>> h.figure
'CM'
OMIT_FROM_DOCS
Fixed storing deduced figures by avoiding duplicate chordStepModifications:
>>> h = harmony.ChordSymbol('CM7omit5')
>>> h.addChordStepModification(harmony.ChordStepModification(modType='add', degree=4))
>>> h.findFigure()
'Cmaj7 subtract 5 add 4'
>>> h.figure
'CM7omit5'
>>> h.figure = h.findFigure()
>>> h.figure
'Cmaj7 subtract 5 add 4'
'''
if self._figure is None:
return self.findFigure()
else:
return self._figure
@figure.setter
def figure(self, value):
self._figure = value
if self._figure:
self._parseFigure()
self._updatePitches()
@property
def key(self):
'''
Gets or sets the current Key (or Scale object) associated with this
Harmony object.
For a given RomanNumeral object. Each sub-classed harmony object
may treat this property differently, for example Roman Numeral
objects update the pitches when the key is changed, but chord
symbol objects do not and the key provides more information about
the musical context from where the harmony object was extracted.
>>> r1 = roman.RomanNumeral('V')
>>> r1.pitches
(<music21.pitch.Pitch G4>, <music21.pitch.Pitch B4>, <music21.pitch.Pitch D5>)
>>> r1.key = key.Key('A')
>>> r1.pitches
(<music21.pitch.Pitch E5>, <music21.pitch.Pitch G#5>, <music21.pitch.Pitch B5>)
Changing the key for a ChordSymbol object does nothing to its pitches, since it's
not dependent on key:
>>> h1 = harmony.ChordSymbol('D-m11')
>>> [str(p) for p in h1.pitches]
['D-2', 'F-2', 'A-2', 'C-3', 'E-3', 'G-3']
>>> h1.key = 'CM' # = C-Major
>>> [str(p) for p in h1.pitches]
['D-2', 'F-2', 'A-2', 'C-3', 'E-3', 'G-3']
But it should change the .romanNumeral object:
>>> y = harmony.ChordSymbol('F')
>>> y.key is None
True
>>> y.romanNumeral
<music21.roman.RomanNumeral I in F major>
>>> y.key = key.Key('C')
>>> y.romanNumeral
<music21.roman.RomanNumeral IV in C major>
'''
return self._key
@key.setter
def key(self, keyOrScale):
if isinstance(keyOrScale, str):
self._key = key.Key(keyOrScale)
else:
self._key = keyOrScale
self._roman = None
@property
def romanNumeral(self):
# noinspection SpellCheckingInspection
'''
Get or set the romanNumeral numeral function of the Harmony as a
:class:`~music21.romanNumeral.RomanNumeral` object. String
representations accepted by RomanNumeral are also accepted.
>>> h = harmony.ChordSymbol('Dmaj7')
>>> h.romanNumeral
<music21.roman.RomanNumeral I7 in D major>
>>> h.romanNumeral = 'III7'
>>> h.romanNumeral
<music21.roman.RomanNumeral III7>
>>> h.romanNumeral.key = key.Key('B')
>>> h.romanNumeral
<music21.roman.RomanNumeral III7 in B major>
>>> h.romanNumeral = roman.RomanNumeral('IV7', 'A')
>>> h.romanNumeral
<music21.roman.RomanNumeral IV7 in A major>
>>> h = harmony.ChordSymbol('B-/D')
>>> h.romanNumeral
<music21.roman.RomanNumeral I6 in B- major>
OMIT_FROM_DOCS
Empty ChordSymbol = empty RomanNumeral:
>>> harmony.ChordSymbol().romanNumeral
<music21.roman.RomanNumeral>
'''
if self._roman is None:
from music21 import roman
if not self.pitches:
return roman.RomanNumeral()
# what is manipulating this so that write as chord matters?
storedWriteAsChord = self._writeAsChord
self.writeAsChord = True
if self.key is None:
self._roman = roman.romanNumeralFromChord(self, key.Key(self.root()))
else:
self._roman = roman.romanNumeralFromChord(self, self.key)
self._writeAsChord = storedWriteAsChord
return self._roman
@romanNumeral.setter
def romanNumeral(self, value):
if hasattr(value, 'classes') and 'RomanNumeral' in value.classes:
self._roman = value
return
from music21 import roman
try: # try to create
self._roman = roman.RomanNumeral(value)
return
except exceptions21.Music21Exception:
pass
raise HarmonyException(f'not a valid pitch specification: {value}')
@property
def writeAsChord(self):
'''
Boolean attribute of all harmony objects that specifies how this
object will be written to the rendered output (such as musicxml). If `True`
(default for romanNumerals), the chord with pitches is written. If
False (default for ChordSymbols) the harmony symbol is written.
For `NoChord` objects, writeAsChord means to write as a rest.
'''
return self._writeAsChord
@writeAsChord.setter
def writeAsChord(self, val):
self._writeAsChord = val
# try:
# self._updatePitches()
# except exceptions21.Music21Exception:
# pass
if val and self.duration.quarterLength == 0:
self.duration = duration.Duration(1)
# PUBLIC METHODS #
[docs]
def addChordStepModification(self, degree, *, updatePitches=True):
'''
Add a harmony degree specification to this Harmony as a
:class:`~music21.harmony.ChordStepModification` object.
>>> hd = harmony.ChordStepModification('add', 4)
>>> h = harmony.ChordSymbol()
>>> h.addChordStepModification(hd)
>>> h.addChordStepModification('juicy')
Traceback (most recent call last):
music21.harmony.HarmonyException: cannot add this object as a degree: juicy
Alteration will also impact the pitches,
if the keyword argument updatePitches is given as True
>>> h = harmony.ChordSymbol('C')
>>> mod = harmony.ChordStepModification('alter', 5, -1)
>>> h.addChordStepModification(mod, updatePitches=True)
>>> h.pitches
(<music21.pitch.Pitch C3>, <music21.pitch.Pitch E3>, <music21.pitch.Pitch G-3>)
* Changed in v7: updatePitches is True by default.
'''
if not isinstance(degree, ChordStepModification):
# TODO: possibly create ChordStepModification objects from other
# specifications
raise HarmonyException(
f'cannot add this object as a degree: {degree}')
if degree not in self.chordStepModifications:
self.chordStepModifications.append(degree)
if updatePitches:
self._updatePitches()
[docs]
def getChordStepModifications(self):
'''
Return all harmony degrees as a list.
'''
return self.chordStepModifications
# ------------------------------------------------------------------------------
class ChordStepModificationException(exceptions21.Music21Exception):
pass
# ------------------------------------------------------------------------------
[docs]
class ChordStepModification(prebase.ProtoM21Object):
'''
ChordStepModification objects define the specification of harmony degree
alterations, subtractions, or additions, used in
:class:`~music21.harmony.Harmony` objects, which includes
harmony.ChordSymbol objects (and will include harmony.RomanNumeral
objects).
- degree-value element: indicates degree in chord, positive integers only
- degree-alter: indicates semitone alteration of degree, positive and
negative integers only
- degree-type: add, alter, or subtract
- if `add`: degree-alter is relative to a dominant chord (major and
perfect intervals except for a minor seventh)
- if `alter` or `subtract`: degree-alter is relative to degree already in
the chord based on its kind element
>>> hd = harmony.ChordStepModification('add', 4)
>>> hd
<music21.harmony.ChordStepModification modType=add
degree=4 interval=<music21.interval.Interval P1>>
>>> hd = harmony.ChordStepModification('alter', 3, 1)
>>> hd
<music21.harmony.ChordStepModification modType=alter
degree=3 interval=<music21.interval.Interval A1>>
'''
# FROM MUSIC XML DOCUMENTATION - FOR DEVELOPER'S REFERENCE
# The degree element is used to add, alter, or subtract
# individual notes in the chord. The degree-value element
# is a number indicating the degree of the chord (1 for
# the root, 3 for third, etc). The degree-alter element
# is like the alter element in notes: 1 for sharp, -1 for
# flat, etc. The degree-type element can be `add`, `alter`, or
# `subtract`. If the degree-type is alter or subtract, the
# degree-alter is relative to the degree already in the
# chord based on its kind element. If the degree-type is
# `add`, the degree-alter is relative to a dominant chord
# (major and perfect intervals except for a minor
# seventh). The print-object attribute can be used to
# keep the degree from printing separately when it has
# already taken into account in the text attribute of
# the kind element. The plus-minus attribute is used to
# indicate if plus and minus symbols should be used
# instead of sharp and flat symbols to display the degree
# alteration; it is `no` by default. The degree-value and
# degree-type text attributes specify how the value and
# type of the degree should be displayed.
#
# A harmony of kind "other" can be spelled explicitly by
# using a series of degree elements together with a root.
# INITIALIZER #
def __init__(self, modType=None, degree=None, intervalObj=None) -> None:
self._modType: str|None = None # add, alter, subtract
self._interval: interval.Interval # alteration of degree, alter ints in mxl
self._degree: int|None = None # the degree number, where 3 is the third
# use properties if defined: runs certain type conversions
if modType is not None:
self.modType = modType
if degree is not None:
self.degree = degree
if intervalObj is not None:
self.interval = intervalObj
else:
self.interval = interval.Interval('P1')
# SPECIAL METHODS #
def _reprInternal(self):
return f'modType={self.modType} degree={self.degree} interval={self.interval}'
[docs]
def __eq__(self, other):
return (
isinstance(other, ChordStepModification)
and self.modType == other.modType
and self.degree == other.degree
and self.interval == other.interval
)
# PUBLIC PROPERTIES #
@property
def degree(self):
'''
Returns or sets an integer specifying the scale degree
that this ChordStepModification alters.
>>> hd = harmony.ChordStepModification()
>>> hd.degree = 3
>>> hd.degree
3
>>> hd.degree = 'juicy'
Traceback (most recent call last):
music21.harmony.ChordStepModificationException: not a valid degree: juicy
'''
return self._degree
@degree.setter
def degree(self, expr):
if expr is not None and common.isNum(expr):
self._degree = int(expr) # should always be an integer
return
raise ChordStepModificationException(
f'not a valid degree: {expr}')
@property
def interval(self):
'''
Get or set the alteration of this degree as a
:class:`~music21.interval.Interval` object, generally
as a type of ascending or descending augmented unison.
>>> hd = harmony.ChordStepModification()
>>> hd.interval = 1
>>> hd.interval
<music21.interval.Interval A1>
>>> hd.interval = -2
>>> hd.interval
<music21.interval.Interval AA-1>
>>> hd.interval = 0
>>> hd.interval
<music21.interval.Interval P1>
>>> hd.interval = interval.Interval('m3')
>>> hd.interval
<music21.interval.Interval m3>
More than 3 half step alteration gets
an interval that isn't a prime.
>>> hd.interval = -4
>>> hd.interval
<music21.interval.Interval M-3>
'''
return self._interval
@interval.setter
def interval(self, value):
if value in (None,):
self._interval = None
elif isinstance(value, interval.Interval):
# an interval object: set directly
self._interval = value
else:
# accept numbers to permit loading from mxl alter specs
numAs = abs(value)
if numAs <= 3:
if numAs == 0:
aStr = 'P'
else:
aStr = 'a' * numAs
aStr += '1'
if value < 0:
aStr += '-'
self._interval = interval.Interval(aStr)
else: # try to create interval object
self._interval = interval.Interval(value)
@property
def modType(self):
'''
Get or set the ChordStepModification modification type, where
permitted types are the strings add, subtract, or alter.
>>> hd = harmony.ChordStepModification()
>>> hd.modType = 'add'
>>> hd.modType
'add'
>>> hd.modType = 'juicy'
Traceback (most recent call last):
music21.harmony.ChordStepModificationException: not a valid degree modification type: juicy
'''
return self._modType
@modType.setter
def modType(self, expr):
if expr is not None and isinstance(expr, str):
if expr.lower() in ['add', 'subtract', 'alter']:
self._modType = expr.lower()
return
raise ChordStepModificationException(
f'not a valid degree modification type: {expr}')
# ------------------------------------------------------------------------------
[docs]
def addNewChordSymbol(chordTypeName, fbNotationString, AbbreviationList):
# noinspection SpellCheckingInspection
'''
Add a new chord symbol:
>>> harmony.addNewChordSymbol('BethChord', '1,3,-6,#9', ['MH', 'beth'])
>>> [str(p) for p in harmony.ChordSymbol('BMH').pitches]
['B2', 'C##3', 'D#3', 'G3']
>>> harmony.ChordSymbol('Cbeth').pitches
(<music21.pitch.Pitch C3>, <music21.pitch.Pitch D#3>,
<music21.pitch.Pitch E3>, <music21.pitch.Pitch A-3>)
>>> harmony.ChordSymbol('C-beth').pitches
(<music21.pitch.Pitch C-3>, <music21.pitch.Pitch D3>,
<music21.pitch.Pitch E-3>, <music21.pitch.Pitch A--3>)
OMIT_FROM_DOCS
>>> harmony.ChordSymbol(root='Cb', kind='BethChord').pitches
(<music21.pitch.Pitch C-3>, <music21.pitch.Pitch D3>,
<music21.pitch.Pitch E-3>, <music21.pitch.Pitch A--3>)
>>> harmony.ChordSymbol(root='C-', kind='BethChord').pitches
(<music21.pitch.Pitch C-3>, <music21.pitch.Pitch D3>,
<music21.pitch.Pitch E-3>, <music21.pitch.Pitch A--3>)
>>> harmony.removeChordSymbols('BethChord')
'''
CHORD_TYPES[chordTypeName] = [fbNotationString, AbbreviationList]
[docs]
def changeAbbreviationFor(chordType, changeTo):
'''
Change the current Abbreviation used for a certain
:class:`music21.harmony.ChordSymbol` chord type
>>> harmony.getCurrentAbbreviationFor('minor')
'm'
>>> harmony.changeAbbreviationFor('minor', 'min')
>>> harmony.getCurrentAbbreviationFor('minor')
'min'
OMIT_FROM_DOCS
>>> harmony.changeAbbreviationFor('minor', 'm') # must change it back for the rest of doctests
'''
CHORD_TYPES[chordType][1].insert(0, changeTo)
[docs]
def chordSymbolFromChord(inChord: chord.Chord) -> ChordSymbol:
'''
Get the :class:`~music21.harmony.chordSymbol` object from the chord, using
:meth:`music21.harmony.Harmony.chordSymbolFigureFromChord`
>>> c = chord.Chord(['D3', 'F3', 'A4', 'B-5'])
>>> symbol = harmony.chordSymbolFromChord(c)
>>> symbol
<music21.harmony.ChordSymbol B-maj7/D>
>>> c.pitches == symbol.pitches
True
'''
cs = ChordSymbol(chordSymbolFigureFromChord(inChord))
cs.pitches = inChord.pitches
return cs
[docs]
def getAbbreviationListGivenChordType(chordType):
'''
Get the Abbreviation list (all allowed Abbreviations that map to this
:class:`music21.harmony.ChordSymbol` object):
>>> harmony.getAbbreviationListGivenChordType('minor-major-13th')
['mM13', 'minmaj13']
'''
return CHORD_TYPES[chordType][1]
[docs]
def getCurrentAbbreviationFor(chordType):
'''
Return the current Abbreviation for a given
:class:`music21.harmony.ChordSymbol` chordType:
>>> harmony.getCurrentAbbreviationFor('dominant-seventh')
'7'
'''
return getAbbreviationListGivenChordType(chordType)[0]
[docs]
def getNotationStringGivenChordType(chordType):
'''
Get the notation string (fb-notation style) associated with this
:class:`music21.harmony.ChordSymbol` chordType
>>> harmony.getNotationStringGivenChordType('German')
'1,-3,#4,-6'
'''
return CHORD_TYPES[chordType][0]
[docs]
def removeChordSymbols(chordType):
'''
Remove the given chord type from the CHORD_TYPES dictionary, so it
can no longer be identified or parsed by harmony methods.
'''
del CHORD_TYPES[chordType]
# --------------------------------------------------------------------------
realizerScaleCache: dict[tuple[str, str], realizerScale.FiguredBassScale] = {}
# --------------------------------------------------------------------------
[docs]
class ChordSymbol(Harmony):
# noinspection SpellCheckingInspection
r'''
Class representing the Chord Symbols commonly found on lead sheets.
Chord Symbol objects can be instantiated one of two main ways:
1. when music xml is parsed by the music21 converter, xml Chord Symbol tags
are interpreted as Chord Symbol objects with a root and kind attribute.
If bass is not specified, the bass is assumed to be the root
2. by creating a chord symbol object with music21 by passing in the
expression commonly found on leadsheets. Due to the relative diversity
of lead sheet chord syntax, not all expressions are supported. Consult
the examples for the supported syntax, or email us for help.
All :class:`~music21.harmony.ChordSymbol` inherit from
:class:`~music21.chord.Chord` so you can consider these objects as chords,
although they have a unique representation in a score. ChordSymbols, unlike
chords, by default appear as chord symbols in a score and have duration of
0.
To obtain the chord representation of the `ChordSymbol` in the score, change
:attr:`~music21.harmony.Harmony.writeAsChord` to True. Unless otherwise
specified, the duration of this chord object will become 1.0. If you have a
leadsheet, run :func:`music21.harmony.realizeChordSymbolDurations` on the
stream to assign the correct (according to offsets) duration to each
harmony object.)
The music xml-based approach to instantiating Chord Symbol objects:
>>> cs = harmony.ChordSymbol(kind='minor', kindStr='m', root='C', bass='E-')
>>> cs
<music21.harmony.ChordSymbol Cm/E->
>>> cs.chordKind
'minor'
>>> cs.root()
<music21.pitch.Pitch C4>
>>> cs.bass()
<music21.pitch.Pitch E-3>
The second approach to creating a Chord Symbol object, by
passing a regular expression (this list is not exhaustive):
>>> symbols = ['', 'm', '+', 'dim', '7',
... 'M7', 'm7', 'dim7', '7+', 'm7b5', # half-diminished
... 'mM7', '6', 'm6', '9', 'Maj9', 'm9',
... '11', 'Maj11', 'm11', '13',
... 'Maj13', 'm13', 'sus2', 'sus4',
... 'N6', 'It+6', 'Fr+6', 'Gr+6', 'pedal',
... 'power', 'tristan', '/E', 'm7/E-', 'add2',
... '7omit3',]
>>> for s in symbols:
... chordSymbolName = 'C' + s
... h = harmony.ChordSymbol(chordSymbolName)
... pitchNames = [str(p) for p in h.pitches]
... print(f'{chordSymbolName:<10}', end='[')
... print(*pitchNames, sep=', ', end=']\n')
C [C3, E3, G3]
Cm [C3, E-3, G3]
C+ [C3, E3, G#3]
Cdim [C3, E-3, G-3]
C7 [C3, E3, G3, B-3]
CM7 [C3, E3, G3, B3]
Cm7 [C3, E-3, G3, B-3]
Cdim7 [C3, E-3, G-3, B--3]
C7+ [C3, E3, G#3, B-3]
Cm7b5 [C3, E-3, G-3, B-3]
CmM7 [C3, E-3, G3, B3]
C6 [C3, E3, G3, A3]
Cm6 [C3, E-3, G3, A3]
C9 [C3, E3, G3, B-3, D4]
CMaj9 [C3, E3, G3, B3, D4]
Cm9 [C3, E-3, G3, B-3, D4]
C11 [C2, E2, G2, B-2, D3, F3]
CMaj11 [C2, E2, G2, B2, D3, F3]
Cm11 [C2, E-2, G2, B-2, D3, F3]
C13 [C2, E2, G2, B-2, D3, F3, A3]
CMaj13 [C2, E2, G2, B2, D3, F3, A3]
Cm13 [C2, E-2, G2, B-2, D3, F3, A3]
Csus2 [C3, D3, G3]
Csus4 [C3, F3, G3]
CN6 [C3, D-3, E3, G-3]
CIt+6 [C3, F#3, A-3]
CFr+6 [C3, D3, F#3, A-3]
CGr+6 [C3, E-3, F#3, A-3]
Cpedal [C3]
Cpower [C3, G3]
Ctristan [C3, D#3, F#3, A#3]
C/E [E3, G3, C4]
Cm7/E- [E-3, G3, B-3, C4]
Cadd2 [C3, D3, E3, G3]
C7omit3 [C3, G3, B-3]
You can also create a Chord Symbol by writing out each degree,
and any alterations to that degree:
You must explicitly indicate EACH degree (a triad is NOT necessarily implied).
>>> [str(p) for p in harmony.ChordSymbol('C35b7b9#11b13').pitches]
['C2', 'E2', 'G2', 'D-3', 'F#3', 'A-3', 'B-3']
>>> [str(p) for p in harmony.ChordSymbol('C35911').pitches]
['C2', 'E2', 'G2', 'D3', 'F3']
To prevent ambiguity in notation and in accordance with the rest of music21,
if a root or bass is flat, the '-' must be used, and NOT 'b'. However, alterations and chord
abbreviations are specified normally with the 'b' and '#' signs.
>>> dFlat = harmony.ChordSymbol('D-35')
>>> [str(p) for p in dFlat.pitches]
['D-3', 'F3', 'A-3']
>>> [str(p) for p in harmony.ChordSymbol('Db35').pitches]
['D3', 'F3', 'A3']
(Note that this would be much better expressed just as 'Dm'.)
>>> [str(p) for p in harmony.ChordSymbol('D,35b7b9#11b13').pitches]
['D2', 'F#2', 'A2', 'E-3', 'G#3', 'B-3', 'C4']
>>> harmony.ChordSymbol('Am').pitches
(<music21.pitch.Pitch A2>, <music21.pitch.Pitch C3>, <music21.pitch.Pitch E3>)
>>> harmony.ChordSymbol('A-m').pitches
(<music21.pitch.Pitch A-2>, <music21.pitch.Pitch C-3>, <music21.pitch.Pitch E-3>)
>>> harmony.ChordSymbol('A-m').pitches
(<music21.pitch.Pitch A-2>, <music21.pitch.Pitch C-3>, <music21.pitch.Pitch E-3>)
>>> harmony.ChordSymbol('F-dim7').pitches
(<music21.pitch.Pitch F-2>, <music21.pitch.Pitch A--2>,
<music21.pitch.Pitch C--3>, <music21.pitch.Pitch E---3>)
Thanks to David Bolton for catching the bugs tested below:
>>> [str(p) for p in harmony.ChordSymbol('C3579').pitches]
['C2', 'E2', 'G2', 'D3', 'B3']
>>> [str(p) for p in harmony.ChordSymbol('C35b79').pitches]
['C2', 'E2', 'G2', 'D3', 'B-3']
>>> [str(p) for p in harmony.ChordSymbol('C357b9').pitches]
['C2', 'E2', 'G2', 'D-3', 'B3']
When bass is not in chord:
>>> cs = harmony.ChordSymbol(root='E', bass='C', kind='diminished-seventh')
>>> [str(p) for p in cs.pitches]
['C2', 'E3', 'G3', 'B-3', 'D-4']
>>> cs.figure
'Eo7/C'
And now, an example of parsing in the wild:
>>> s = corpus.parse('leadsheet/fosterBrownHair')
>>> initialSymbols = s.flatten().getElementsByClass(harmony.ChordSymbol)[0:5]
>>> [[str(c.name) for c in c.pitches] for c in initialSymbols]
[['F', 'A', 'C'], ['B-', 'D', 'F'], ['F', 'A', 'C'], ['C', 'E', 'G'], ['F', 'A', 'C']]
Test creating an empty chordSymbol:
>>> cs = harmony.ChordSymbol()
>>> cs
<music21.harmony.ChordSymbol>
>>> cs.root('E-')
>>> cs.bass('B-', allow_add=True)
important: we are not asking for transposition, merely specifying the inversion that
the chord should be read in (transposeOnSet = False)
>>> cs.inversion(2, transposeOnSet=False)
>>> cs.romanNumeral = 'I64'
>>> cs.chordKind = 'major'
>>> cs.chordKindStr = 'M'
>>> cs
<music21.harmony.ChordSymbol E-/B->
'''
# INITIALIZER #
def __init__(self,
figure: str|None = None,
root: pitch.Pitch|str|None = None,
bass: pitch.Pitch|str|None = None,
inversion: int|None = None,
kind='',
kindStr='',
**keywords
):
self.chordKind = kind # a string from defined list of chord symbol harmonies
self.chordKindStr = kindStr # the presentation of the kind or label of symbol
super().__init__(figure, root=root, bass=bass, inversion=inversion, **keywords)
if 'duration' not in keywords and 'quarterLength' not in keywords:
self.duration = duration.Duration(0)
if self.chordKind or self.chordKindStr:
self._updatePitches()
# PRIVATE METHODS #
def _adjustOctaves(self, pitches):
if not isinstance(pitches, list):
pitches = list(pitches)
# do this for all ninth, thirteenth, and eleventh chords
# this must be done to get octave spacing right
# possibly rewrite figured bass function with this integrated?
ninths = ['dominant-ninth', 'major-ninth', 'minor-ninth']
elevenths = ['dominant-11th', 'major-11th', 'minor-11th']
thirteenths = ['dominant-13th', 'major-13th', 'minor-13th']
if self.chordKind in ninths:
pitches[1] = pitch.Pitch(pitches[1].name + str(pitches[1].octave + 1))
elif self.chordKind in elevenths:
pitches[1] = pitch.Pitch(pitches[1].name + str(pitches[1].octave + 1))
pitches[3] = pitch.Pitch(pitches[3].name + str(pitches[3].octave + 1))
elif self.chordKind in thirteenths:
pitches[1] = pitch.Pitch(pitches[1].name + str(pitches[1].octave + 1))
pitches[3] = pitch.Pitch(pitches[3].name + str(pitches[3].octave + 1))
pitches[5] = pitch.Pitch(pitches[5].name + str(pitches[5].octave + 1))
else:
return pitches
c = chord.Chord(pitches)
c = c.sortDiatonicAscending()
return list(c.pitches)
def _adjustPitchesForChordStepModifications(
self, pitches: t.Iterable[pitch.Pitch]
) -> list[pitch.Pitch]:
'''
degree-value element: indicates degree in chord, positive integers only
degree-alter: indicates semitone alteration of degree, positive and negative integers only
degree-type: `add`, `alter`, or `subtract`:
if `add`:
degree-alter is relative to a dominant chord (major and perfect
intervals except for a minor seventh)
if `alter` or `subtract`:
degree-alter is relative to degree already in the chord based on its kind element
FROM XML DOCUMENTATION
The degree element is used to add, alter, or subtract
individual notes in the chord. The degree-value element
is a number indicating the degree of the chord (1 for
the root, 3 for third, etc). The degree-alter element
is like the alter element in notes: 1 for sharp, -1 for
flat, etc. The degree-type element can be `add`, `alter`, or
`subtract`. If the degree-type is `alter` or `subtract`, the
degree-alter is relative to the degree already in the
chord based on its kind element. If the degree-type is
`add`, the degree-alter is relative to a dominant chord
(major and perfect intervals except for a minor
seventh). The print-object attribute can be used to
keep the degree from printing separately when it has
already taken into account in the text attribute of
the kind element. The plus-minus attribute is used to
indicate if plus and minus symbols should be used
instead of sharp and flat symbols to display the degree
alteration; it is `no` by default. The degree-value and
degree-type text attributes specify how the value and
type of the degree should be displayed.
A harmony of kind "other" can be spelled explicitly by
using a series of degree elements together with a root.
'''
from music21 import scale
pitches = list(pitches)
chordStepModifications = self.chordStepModifications
if chordStepModifications is None:
return pitches
rootPitch = self.root()
sc = scale.MajorScale(rootPitch)
def typeAdd(hD):
'''
Change the pitches list based on this chordStepModification, adding
a pitch.
'''
pitchToAppend = sc.pitchFromDegree(hD.degree, rootPitch)
if hD.interval and hD.interval.semitones != 0:
# added degrees are relative to dominant chords, which have all major degrees
# except for the seventh which is minor, thus the transposition down one half step.
# Don't do this for flatted transformations:
# C7addb7 is a redundancy, not a double-flatted seventh.
if (
hD.degree == 7
and hD.interval.semitones > 0
and self.chordKind is not None
and self.chordKind != ''
):
pitchToAppend = pitchToAppend.transpose(-1)
pitchToAppend = pitchToAppend.transpose(hD.interval)
if hD.degree >= 7:
pitchToAppend.octave = pitchToAppend.octave + 1
degrees = self._degreesList
if str(hD.degree) in degrees:
for p in pitches:
if sc.getScaleDegreeFromPitch(p) == hD.degree:
pitches.remove(p)
pitches.append(pitchToAppend)
else:
pitches.append(pitchToAppend)
# # for now I won't worry about the octave of the added note
# # if self.bass() is not None:
# # p = sc.pitchFromDegree(hD.degree, self.bass())
# # else:
# # p = sc.pitchFromDegree(hD.degree, self.root())
# if hD.degree == 7 and self.chordKind is not None and self.chordKind != '':
# # don't know why anyone would want
# # to add a seventh to a dominant chord already
# # however, according to documentation
# # added degrees are relative to dominant chords, which have all major degrees
# # except for the seventh which is minor, thus the transposition down
# # one half step
# p = p.transpose(-1)
# self._degreesList.append('-7')
# # degreeForList = '-7'
# else:
# self._degreesList.append(hD.degree)
# # degreeForList = str(hD.degree)
# # adjust the added pitch by degree-alter interval
# if hD.interval:
# p = p.transpose(hD.interval)
# if hD.degree >= 7:
# p.octave = p.octave + 1
# pitches.append(p)
def typeSubtract(hD):
'''
Change the pitches list based on this chordStepModification, removing a pitch.
'''
degrees = self._degreesList
if not degrees:
return
pitchFound = False
for p, degree in zip(pitches, degrees):
degree = degree.replace('-', '')
degree = degree.replace('#', '')
degree = degree.replace('A', '') # A is for 'Altered'
if hD.degree == int(degree):
pitches.remove(p)
pitchFound = True
for degreeString in self._degreesList:
if str(hD.degree) in degreeString:
self._degreesList.remove(degreeString)
break
# if hD.degree not in string,
# should we throw an exception???? for now yes, but maybe later we
# will be more lenient.
if not pitchFound:
raise ChordStepModificationException(
f'Degree not in specified chord: {hD.degree}')
def typeAlter(hD):
'''
alter
'''
pitchFound = False
degrees = self._degreesList
for p, degree in zip(pitches, degrees):
degree = degree.replace('-', '')
degree = degree.replace('#', '')
degree = degree.replace('A', '') # A is for 'Altered'
if hD.degree == int(degree):
# transpose by semitones (positive for up, negative for down)
p = p.transpose(hD.interval, inPlace=True)
pitchFound = True
# for degreeString in self._degreesList:
# if str(hD.degree) in degreeString:
# self._degreesList = self._degreesList.replace(
# degreeString, ('A' + str(hD.degree)))
# # the 'A' stands for altered
# break
# # if hD.degree not in string:
# # should we throw an exception???? for now yes, but maybe later we should.
if not pitchFound:
raise ChordStepModificationException(
f'Degree not in specified chord: {hD.degree}')
# main routines
for chordStepModification in chordStepModifications:
if chordStepModification.modType == 'add':
typeAdd(chordStepModification)
elif chordStepModification.modType == 'subtract':
typeSubtract(chordStepModification)
elif chordStepModification.modType == 'alter':
try:
typeAlter(chordStepModification)
except ChordStepModificationException:
# fix it in place
chordStepModification.modType = 'add'
typeAdd(chordStepModification)
return pitches
def _parseAddAlterSubtract(self, remaining: str, modType: str) -> str:
'''
Removes and parses the first instance of a given `modType` such as
'add', 'alter', 'omit', or 'subtract'. Returns the unparsed remainder.
>>> cs = harmony.ChordSymbol()
>>> cs._parseAddAlterSubtract('add#9omit5', 'add')
'omit5'
>>> cs.chordStepModifications
[<music21.harmony.ChordStepModification
modType=add degree=9 interval=<music21.interval.Interval A1>>]
'''
degree: str = ''
alter: int = 0
startIndex: int = remaining.index(modType) + len(modType)
# Remove modType
remaining = remaining[startIndex:]
if remaining[:1] == 'b':
alter = -1
remaining = remaining[1:]
elif remaining[:1] == '#':
alter = 1
remaining = remaining[1:]
# 11, 13, etc.
if remaining[:2].isnumeric():
degree = remaining[:2]
remaining = remaining[2:]
# 9, 6, 4, etc.
elif remaining[0].isnumeric():
degree = remaining[0]
remaining = remaining[1:]
if degree:
if modType == 'omit':
modType = 'subtract'
self.addChordStepModification(
ChordStepModification(modType, int(degree), alter), updatePitches=False)
return remaining
def _getKindFromShortHand(self, sH):
originalsH = sH
if 'add' in sH:
sH = sH[0:sH.index('add')]
if 'alter' in sH:
sH = sH[0:sH.index('alter')]
if 'omit' in sH:
sH = sH[0:sH.index('omit')]
if 'subtract' in sH:
sH = sH[0:sH.index('subtract')]
if '#' in sH and sH[sH.index('#') + 1].isdigit():
sH = sH[0:sH.index('#')]
if ('b' in sH and sH.index('b') < len(sH) - 1
and sH[sH.index('b') + 1].isdigit()
and 'ob9' not in sH and 'øb9' not in sH):
sH = sH[0:sH.index('b')]
for chordKind in CHORD_TYPES:
for charString in getAbbreviationListGivenChordType(chordKind):
if sH == charString:
self.chordKind = chordKind
return originalsH[len(sH):]
return originalsH
def _hasPitchAboveC4(self, pitches):
for p in pitches:
if p.diatonicNoteNum > 30: # if there are pitches above middle C, bump the octave down
return True
return False
def _hasPitchBelowA1(self, pitches):
for p in pitches:
if p.diatonicNoteNum < 13: # anything below this is just obnoxious
return True
return False
def _notationString(self):
'''
Returns NotationString of ChordSymbolObject which dictates which scale
degrees and how those scale degrees are altered in this chord.
>>> h = harmony.ChordSymbol('F-dim7')
>>> h._notationString()
'1,-3,-5,--7'
'''
notationString = ''
kind = self.chordKind
if kind in CHORD_ALIASES:
kind = CHORD_ALIASES[kind]
if kind in CHORD_TYPES:
notationString = getNotationStringGivenChordType(kind)
else:
notationString = ''
degrees = notationString.replace(',', ' ')
self._degreesList = degrees.split()
return notationString
def _parseFigure(self) -> None:
'''
Translate the figure string (regular expression) into a meaningful
Harmony object by identifying the root, bass, inversion, kind, and
kindStr.
'''
if self.figure == 'Chord Symbol Cannot Be Identified':
return
# remove spaces from prelim Figure
prelimFigure = self.figure
prelimFigure = re.sub(r'\s', '', prelimFigure)
# Get Root:
if ',' in prelimFigure:
root = prelimFigure[0:prelimFigure.index(',')]
st = prelimFigure.replace(',', '')
st = st.replace(root, '')
prelimFigure = prelimFigure.replace(',', '')
else:
m1 = re.match(r'[A-Ga-g][#-]*', prelimFigure) # match not case-sensitive,
if m1:
root = m1.group()
# remove the root and bass from the string and any additions/omissions/alterations/
st = prelimFigure.replace(m1.group(), '', 1)
else:
raise ValueError(f'Chord {prelimFigure} does not begin '
+ 'with a valid root note.')
if root:
self.root(pitch.Pitch(root))
# Get optional Bass:
m2 = re.search(r'/[A-Ga-g][#-]*', prelimFigure) # match not case-sensitive
remaining = st
if m2:
bass = m2.group()
bass = bass.replace('/', '')
self.bass(bass, allow_add=True)
# remove the root and bass from the string
remaining = st.replace(m2.group(), '')
st = self._getKindFromShortHand(remaining)
ALTER_TYPES = ('add', 'alter', 'omit', 'subtract')
searchStart: int = 1000 # not -1 for the sake of min(), below
for alterType in ALTER_TYPES:
try:
searchStart = min(remaining.index(alterType), searchStart)
except ValueError:
pass
searchStringForAlterTypes: str = remaining[searchStart:]
substring: str = ''
i = 0
while searchStringForAlterTypes and i < len(searchStringForAlterTypes):
for char in searchStringForAlterTypes:
i += 1
if char.isalpha():
substring += char
if substring in ALTER_TYPES:
searchStringForAlterTypes = self._parseAddAlterSubtract(
searchStringForAlterTypes, substring)
substring = ''
i = 0
break
st = st.replace(',', '')
# Unsafe to proceed until every alterType and anything following
# is stripped from 'st'
for alterType in ALTER_TYPES:
if alterType in st:
st = st[:st.index(alterType)]
if 'b' in st or '#' in st:
splitter = re.compile('([b#]+[^b#]+)')
alterations = splitter.split(st)
else:
alterations = [st]
indexes = []
altCopy = []
for itemString in alterations:
if not itemString:
continue
justInts = itemString.replace('b', '')
justInts = justInts.replace('#', '')
try:
justInts = int(justInts)
except ValueError as ve:
raise ValueError(
f'Invalid chord abbreviation {st!r}; see '
+ 'music21.harmony.CHORD_TYPES for valid '
+ 'abbreviations or specify all alterations.'
) from ve
if justInts > 20: # MSC: what is this doing?
skipNext = False
i = 0
charString = ''
for char in itemString:
if not skipNext:
if char == '1':
indexes.append(itemString[i] + itemString[i + 1])
skipNext = True
elif char in ('b', '#'):
charString = charString + char
else:
charString = charString + char
indexes.append(charString)
charString = ''
else:
skipNext = False
i = i + 1
else:
altCopy.append(itemString)
for item in indexes:
altCopy.append(item)
alterations = altCopy
degrees = []
for alteration in alterations:
if alteration != '':
if 'b' in alteration:
semiToneAlter = -1 * alteration.count('b')
else:
semiToneAlter = alteration.count('#')
m3 = re.search(r'[1-9]+', alteration)
if m3:
degrees.append([int(m3.group()), semiToneAlter])
for degree, alterBy in degrees:
self.addChordStepModification(
ChordStepModification('add', degree, alterBy), updatePitches=False)
def _updatePitches(self):
'''
TODO: EXTREMELY SLOW!
Calculate the pitches in the chord symbol and update all associated
variables, including bass, root, inversion and chord:
>>> CS = harmony.ChordSymbol
>>> [str(pi) for pi in CS(root='C', bass='E', kind='major').pitches]
['E3', 'G3', 'C4']
>>> [str(pi) for pi in CS(root='C', bass='G', kind='major').pitches]
['G2', 'C3', 'E3']
>>> [str(pi) for pi in CS(root='C', kind='minor').pitches]
['C3', 'E-3', 'G3']
>>> [str(pi) for pi in CS(root='C', bass='B', kind='major-ninth').pitches]
['B2', 'C3', 'D3', 'E3', 'G3']
>>> [str(pi) for pi in CS(root='D', bass='F', kind='minor-seventh').pitches]
['F3', 'A3', 'C4', 'D4']
Note that this ChordSymbol creates what looks like a B- minor-seventh
chord in first inversion, but is considered to be a D- chord in root
position:
>>> dFlatMaj6 = CS('D-6')
>>> [str(pi) for pi in dFlatMaj6.pitches]
['D-3', 'F3', 'A-3', 'B-3']
>>> dFlatMaj6.root()
<music21.pitch.Pitch D-3>
>>> dFlatMaj6.inversion()
0
OMIT_FROM_DOCS
>>> CS('E7omit3').root().nameWithOctave
'E3'
>>> CS('E7omit5/G#').bass().nameWithOctave
'G#2'
>>> CS('E9omit5/G#').root().nameWithOctave
'E3'
>>> CS('E11omit3').root().nameWithOctave
'E2'
'''
if 'root' not in self._overrides or 'bass' not in self._overrides or self.chordKind is None:
return
from music21.figuredBass import realizerScale
# create figured bass scale with root as scale
scaleInitTuple = (self._overrides['root'].name, 'major')
if scaleInitTuple in realizerScaleCache:
fbScale = realizerScaleCache[scaleInitTuple]
else:
fbScale = realizerScale.FiguredBassScale(self._overrides['root'], 'major')
realizerScaleCache[scaleInitTuple] = fbScale
# render in the 3rd octave by default
self._overrides['root'].octave = 3
self._overrides['bass'].octave = 3
if self._notationString():
pitches = fbScale.getSamplePitches(self._overrides['root'], self._notationString())
# remove duplicated bass note due to figured bass method.
pitches.pop(0)
else:
pitches = []
pitches.append(self._overrides['root'])
if self._overrides['bass'] not in pitches:
pitches.append(self._overrides['bass'])
pitches = self._adjustOctaves(pitches)
if self._overrides['root'].name != self._overrides['bass'].name:
inversionNum = self.inversion()
if not self.inversionIsValid(inversionNum):
# there is a bass, yet no normal inversion was found: must be added note
inversionNum = None
# arbitrary octave, must be below root,
# which was arbitrarily chosen as 3 above
self._overrides['bass'].octave = 2
pitches.append(self._overrides['bass'])
else:
self.inversion(None, transposeOnSet=False)
inversionNum = None
pitches = self._adjustPitchesForChordStepModifications(pitches)
if inversionNum not in (0, None):
for p in pitches[0:inversionNum]:
p.octave = p.octave + 1
# Repeat if 9th/11th/13th chord in 4th inversion or greater
if inversionNum > 3:
p.octave = p.octave + 1
# if after bumping up the octaves, there are still pitches below bass pitch
# bump up their octaves
# bassPitch = pitches[inversionNum]
# self.bass(bassPitch)
for p in pitches:
if p.diatonicNoteNum < self._overrides['bass'].diatonicNoteNum:
p.octave = p.octave + 1
while self._hasPitchAboveC4(pitches):
for thisPitch in pitches:
thisPitch.octave -= 1
# but if this has created pitches below lowest note (the A 3 octaves below middle C)
# on a standard piano, we're going to have to bump all the octaves back up
while self._hasPitchBelowA1(pitches):
for thisPitch in pitches:
thisPitch.octave += 1
self.pitches = tuple(pitches)
self.sortDiatonicAscending(inPlace=True)
# set overrides to be pitches in the harmony
# self._overrides = {} # JTW: was wiping legit overrides such as root=C from 'C6'
self.bass(self.bass(), allow_add=True)
self.root(self.root())
# PUBLIC METHODS #
[docs]
def inversionIsValid(self, inversion):
'''
Returns true if the provided inversion exists for the given pitches of
the chord. If not, it returns false and the getPitches method then
appends the bass pitch to the chord.
'''
sevenths = (
'French',
'German',
'Italian',
'Neapolitan',
'Tristan',
'augmented-seventh',
'diminished-seventh',
'dominant-seventh',
'half-diminished',
'major-minor',
'major-seventh',
'minor-seventh',
)
ninths = (
'dominant-ninth',
'major-ninth',
'minor-ninth',
)
elevenths = (
'dominant-11th',
'major-11th',
'minor-11th',
)
thirteenths = (
'dominant-13th',
'major-13th',
'minor-13th',
)
if inversion == 5 and (
self.chordKind in thirteenths
or self.chordKind in elevenths
):
return True
elif inversion == 4 and (
self.chordKind in elevenths
or self.chordKind in thirteenths
or self.chordKind in ninths
):
return True
elif inversion == 3 and (
self.chordKind in sevenths
or self.chordKind in ninths
or self.chordKind in elevenths
or self.chordKind in thirteenths
):
return True
elif (inversion in (2, 1)
and self.chordKind != 'pedal'):
return True
elif inversion is None:
return False
else:
return False
[docs]
def transpose(self, value, *, inPlace=False) -> t.Self|None:
'''
Overrides :meth:`~music21.chord.Chord.transpose` so that this ChordSymbol's
`figure` is appropriately cleared afterward.
>>> cs = harmony.ChordSymbol('Am')
>>> cs.figure
'Am'
>>> cs.transpose(1)
<music21.harmony.ChordSymbol B-m>
>>> cs.transpose(5, inPlace=True)
>>> cs
<music21.harmony.ChordSymbol Dm>
>>> cs.figure
'Dm'
'''
post = super().transpose(value, inPlace=inPlace)
if not inPlace:
post.figure = None
return post
else:
self.figure = None
return None
[docs]
class NoChord(ChordSymbol):
'''
Class representing a special 'no chord' ChordSymbol used to explicitly
encode absence of chords. This is especially useful to stop a chord
without playing another.
>>> from music21.harmony import ChordSymbol, NoChord
>>> s = stream.Score()
>>> s.repeatAppend(note.Note('C'), 4)
>>> s.append(ChordSymbol('C'))
>>> s.repeatAppend(note.Note('C'), 4)
>>> s.append(NoChord())
>>> s.repeatAppend(note.Note('C'), 4)
>>> s = s.makeMeasures()
See how the chordSymbol of C stops at offset 8 rather
than continuing, thanks to the NoChord object.
>>> s = harmony.realizeChordSymbolDurations(s)
>>> s.show('text', addEndTimes=True)
{0.0 - 0.0} <music21.clef.BassClef>
{0.0 - 0.0} <music21.meter.TimeSignature 4/4>
{0.0 - 1.0} <music21.note.Note C>
{1.0 - 2.0} <music21.note.Note C>
{2.0 - 3.0} <music21.note.Note C>
{3.0 - 4.0} <music21.note.Note C>
{4.0 - 8.0} <music21.harmony.ChordSymbol C>
{4.0 - 5.0} <music21.note.Note C>
{5.0 - 6.0} <music21.note.Note C>
{6.0 - 7.0} <music21.note.Note C>
{7.0 - 8.0} <music21.note.Note C>
{8.0 - 12.0} <music21.harmony.NoChord N.C.>
{8.0 - 9.0} <music21.note.Note C>
{9.0 - 10.0} <music21.note.Note C>
{10.0 - 11.0} <music21.note.Note C>
{11.0 - 12.0} <music21.note.Note C>
{12.0 - 12.0} <music21.bar.Barline type=final>
>>> c_major = s.getElementsByClass(ChordSymbol).first()
>>> c_major.duration
<music21.duration.Duration 4.0>
>>> c_major.offset
4.0
Other text than the default of 'N.C.' can be given:
>>> nc2 = NoChord('NC')
>>> nc2
<music21.harmony.NoChord NC>
>>> nc2.pitches
()
Note that even if the text is a valid chord abbreviation, no
pitches are generated. This feature may be useful for adding
the appearance of ChordSymbols in a piece without having them
be realized.
>>> nc2 = NoChord('C7')
>>> nc2
<music21.harmony.NoChord C7>
>>> nc2.pitches
()
'''
def __init__(
self,
figure: str|None = None,
kind: str|None = 'none',
kindStr: str|None = None,
**keywords
):
super().__init__(figure, kind=kind, kindStr=kindStr or figure or 'N.C.', **keywords)
if self._figure is None:
self._figure = self.chordKindStr
[docs]
def root(self, newroot=None, *, find=None):
# Ignore newroot, and set find to "False" to always return None
return None
[docs]
def bass(self, newbass=None, *, find=None, allow_add=False):
# Ignore newbass, and set find to "False" to always return None
return None
def _parseFigure(self):
# do nothing, everything is already set.
return
[docs]
def transpose(self, _value, *, inPlace=False) -> t.Self|None:
'''
Overrides :meth:`~music21.chord.Chord.transpose` to do nothing.
>>> nc = harmony.NoChord()
>>> nc.figure
'N.C.'
>>> nc.transpose(8, inPlace=True)
>>> nc.figure
'N.C.'
'''
if not inPlace:
return copy.deepcopy(self)
else:
return None
# ------------------------------------------------------------------------------
[docs]
def realizeChordSymbolDurations(piece):
'''
Returns music21 stream with duration attribute of chord symbols correctly
set. Duration of chord symbols is based on the surrounding chord symbols;
The chord symbol continues duration until another chord symbol is located
or the piece ends.
>>> s = stream.Score()
>>> s.append(harmony.ChordSymbol('C'))
>>> s.repeatAppend(note.Note('C'), 4)
>>> s.append(harmony.ChordSymbol('C'))
>>> s.repeatAppend(note.Note('C'), 4)
>>> s = s.makeMeasures()
>>> harmony.realizeChordSymbolDurations(s).show('text')
{0.0} <music21.clef.BassClef>
{0.0} <music21.meter.TimeSignature 4/4>
{0.0} <music21.harmony.ChordSymbol C>
{0.0} <music21.note.Note C>
{1.0} <music21.note.Note C>
{2.0} <music21.note.Note C>
{3.0} <music21.note.Note C>
{4.0} <music21.harmony.ChordSymbol C>
{4.0} <music21.note.Note C>
{5.0} <music21.note.Note C>
{6.0} <music21.note.Note C>
{7.0} <music21.note.Note C>
{8.0} <music21.bar.Barline type=final>
If only one chord symbol object is present:
>>> s = stream.Score()
>>> s.append(harmony.ChordSymbol('C'))
>>> s.repeatAppend(note.Note('C'), 4)
>>> s = s.makeMeasures()
>>> harmony.realizeChordSymbolDurations(s).show('text')
{0.0} <music21.clef.BassClef>
{0.0} <music21.meter.TimeSignature 4/4>
{0.0} <music21.harmony.ChordSymbol C>
{0.0} <music21.note.Note C>
{1.0} <music21.note.Note C>
{2.0} <music21.note.Note C>
{3.0} <music21.note.Note C>
{4.0} <music21.bar.Barline type=final>
If a ChordSymbol object exists followed by many notes, duration represents
all those notes (how else can the computer know to end the chord? if
there's no chord following it other than end the chord at the end of the
piece?).
>>> s = stream.Score()
>>> s.repeatAppend(note.Note('C'), 4)
>>> s.append(harmony.ChordSymbol('C'))
>>> s.repeatAppend(note.Note('C'), 8)
>>> s = s.makeMeasures()
>>> harmony.realizeChordSymbolDurations(s).show('text')
{0.0} <music21.clef.BassClef>
{0.0} <music21.meter.TimeSignature 4/4>
{0.0} <music21.note.Note C>
{1.0} <music21.note.Note C>
{2.0} <music21.note.Note C>
{3.0} <music21.note.Note C>
{4.0} <music21.harmony.ChordSymbol C>
{4.0} <music21.note.Note C>
{5.0} <music21.note.Note C>
{6.0} <music21.note.Note C>
{7.0} <music21.note.Note C>
{8.0} <music21.note.Note C>
{9.0} <music21.note.Note C>
{10.0} <music21.note.Note C>
{11.0} <music21.note.Note C>
{12.0} <music21.bar.Barline type=final>
'''
pf = piece.flatten()
onlyChords = pf.getElementsByClass(ChordSymbol).stream()
first = True
lastChord = None
if len(onlyChords) > 1:
for cs in onlyChords:
if first:
first = False
lastChord = cs
continue
else:
qlDiff = pf.elementOffset(cs) - pf.elementOffset(lastChord)
lastChord.duration.quarterLength = qlDiff
if onlyChords.index(cs) == (len(onlyChords) - 1):
cs.duration.quarterLength = pf.highestTime - pf.elementOffset(cs)
lastChord = cs
return pf
elif len(onlyChords) == 1:
onlyChords[0].duration.quarterLength = pf.highestTime - pf.elementOffset(onlyChords[0])
return pf
else:
return piece
# ------------------------------------------------------------------------------
class Test(unittest.TestCase):
def testChordAttributes(self):
from music21 import harmony
cs = harmony.ChordSymbol('Cm')
self.assertEqual(str(cs), '<music21.harmony.ChordSymbol Cm>')
self.assertEqual(
str(cs.pitches),
'(<music21.pitch.Pitch C3>, <music21.pitch.Pitch E-3>, <music21.pitch.Pitch G3>)')
self.assertEqual(str(cs.bass()), 'C3')
self.assertTrue(cs.isConsonant())
def testBasic(self):
from music21 import harmony
h = harmony.Harmony()
hd = harmony.ChordStepModification('add', 4)
h.addChordStepModification(hd)
self.assertEqual(len(h.chordStepModifications), 1)
def testChordKindSetting(self):
from music21 import harmony
cs = harmony.ChordSymbol()
cs.root('E-')
cs.bass('B-', allow_add=True)
cs.inversion(2, transposeOnSet=False)
cs.romanNumeral = 'I64'
cs.chordKind = 'major'
cs.chordKindStr = 'M'
self.assertEqual(repr(cs), '<music21.harmony.ChordSymbol E-/B->')
def testDoubleSharpsEtc(self):
# noinspection SpellCheckingInspection
cisisdim = chord.Chord(('c##5', 'e#5', 'g#5'))
fig = chordSymbolFigureFromChord(cisisdim)
self.assertEqual(fig, 'C##dim')
def testChordSymbolSetsBassOctave(self):
d = ChordSymbol('Cm/E-')
root = d.root()
self.assertEqual(root.nameWithOctave, 'C4')
b = d.bass()
self.assertEqual(b.nameWithOctave, 'E-3')
def testHarmonyPreservesInversionAndBass(self):
'''
Test that bass is preserved even when both bass and inversion are given.
'''
explicitFm6 = ChordSymbol(root='F', bass='A-', inversion=1, kind='minor')
self.assertEqual(explicitFm6.inversion(), 1)
self.assertEqual(explicitFm6.bass(find=False).name, 'A-')
self.assertEqual(explicitFm6.root(find=False).name, 'F')
fm6bassOctave = explicitFm6.bass(find=False).octave
fm6rootOctave = explicitFm6.root(find=False).octave
self.assertIsNotNone(fm6bassOctave)
self.assertIsNotNone(fm6rootOctave)
assert fm6bassOctave is not None
assert fm6rootOctave is not None
self.assertLess(fm6bassOctave, fm6rootOctave)
def testClassSortOrderHarmony(self):
'''
This tests a former bug in getContextByClass
because ChordSymbol used to have the same `.classSortOrder`
as Note.
'''
from music21 import note
from music21 import stream
cs = ChordSymbol('C')
n = note.Note('C')
m = stream.Measure(1)
m.insert(0, n)
m.insert(0, cs)
self.assertIs(n.getContextByClass('ChordSymbol'), cs)
# check that it works also with append
cs = ChordSymbol('C')
n = note.Note('C')
n.duration.quarterLength = 0
m = stream.Measure(1)
m.append(n)
m.append(cs)
self.assertIs(n.getContextByClass('ChordSymbol'), cs)
def testNoChord(self):
from music21 import harmony
nc = harmony.NoChord()
self.assertEqual('none', nc.chordKind)
self.assertEqual('N.C.', nc.chordKindStr)
self.assertEqual('N.C.', nc.figure)
nc = harmony.NoChord('NC')
self.assertEqual('none', nc.chordKind)
self.assertEqual('NC', nc.chordKindStr)
self.assertEqual('NC', nc.figure)
nc = harmony.NoChord('None')
self.assertEqual('none', nc.chordKind)
self.assertEqual('None', nc.chordKindStr)
self.assertEqual('None', nc.figure)
nc = harmony.NoChord(kind='none')
self.assertEqual('none', nc.chordKind)
self.assertEqual('N.C.', nc.chordKindStr)
self.assertEqual('N.C.', nc.figure)
nc = harmony.NoChord(kindStr='No Chord')
self.assertEqual('none', nc.chordKind)
self.assertEqual('No Chord', nc.chordKindStr)
self.assertEqual('No Chord', nc.figure)
nc = harmony.NoChord('NC', kindStr='No Chord')
self.assertEqual('none', nc.chordKind)
self.assertEqual('No Chord', nc.chordKindStr)
self.assertEqual('NC', nc.figure)
nc = harmony.NoChord(root='C', bass='E', kind='none')
self.assertEqual('N.C.', nc.chordKindStr)
self.assertEqual('N.C.', nc.figure)
self.assertEqual(str(nc), '<music21.harmony.NoChord N.C.>')
self.assertEqual(0, len(nc.pitches))
self.assertIsNone(nc.root())
self.assertIsNone(nc.bass())
nc._updatePitches()
self.assertEqual(0, len(nc.pitches))
def testInvalidRoots(self):
from music21 import harmony
with self.assertRaises(ValueError) as context:
harmony.ChordSymbol('H-7')
self.assertEqual(
str(context.exception),
'Chord H-7 does not begin with a valid root note.'
)
with self.assertRaises(ValueError) as context:
# noinspection SpellCheckingInspection
harmony.ChordSymbol('Garg7')
self.assertEqual(
str(context.exception),
"Invalid chord abbreviation 'arg7'; see "
+ 'music21.harmony.CHORD_TYPES for valid '
+ 'abbreviations or specify all alterations.'
)
def testInvalidSymbol(self):
from music21 import harmony
c = chord.Chord(('A#', 'C', 'E'))
cs = harmony.chordSymbolFromChord(c)
self.assertEqual(cs.figure, 'Chord Symbol Cannot Be Identified')
def testRegexEdgeCases(self):
cs = ChordSymbol('FFr+6')
self.assertEqual([p.name for p in cs.pitches], ['F', 'G', 'B', 'D-'])
cs = ChordSymbol('dadd6')
self.assertEqual([p.name for p in cs.pitches], ['D', 'F#', 'A', 'B'])
cs = ChordSymbol('atristan')
self.assertEqual([p.name for p in cs.pitches], ['A', 'B#', 'D#', 'F##'])
def runTestOnChord(self, xmlString, figure, pitches):
'''
Run a series of tests on the given chord.
xmlString: an XML harmony object
figure: the equivalent figure representation
pitches: the list of pitches of the chord
'''
from xml.etree.ElementTree import fromstring as EL
from music21 import musicxml
pitches = tuple(pitch.Pitch(p) for p in pitches)
MP = musicxml.xmlToM21.MeasureParser()
mxHarmony = EL(xmlString)
cs1 = MP.xmlToChordSymbol(mxHarmony)
cs2 = ChordSymbol(cs1.figure)
cs3 = ChordSymbol(figure)
self.assertEqual(pitches, cs1.pitches)
self.assertEqual(pitches, cs2.pitches)
self.assertEqual(pitches, cs3.pitches)
kind1 = cs1.chordKind
kind2 = cs2.chordKind
kind3 = cs3.chordKind
if kind1 in CHORD_ALIASES:
kind1 = CHORD_ALIASES[kind1]
if kind2 in CHORD_ALIASES:
kind2 = CHORD_ALIASES[kind2]
if kind3 in CHORD_ALIASES:
kind3 = CHORD_ALIASES[kind3]
self.assertEqual(kind1, kind2)
self.assertEqual(kind1, kind3)
self.assertEqual(cs1.root(), cs2.root())
self.assertEqual(cs1.root(), cs3.root())
self.assertEqual(cs1.bass(), cs2.bass())
self.assertEqual(cs1.bass(), cs3.bass())
def testChordWithBass(self):
xmlString = '''
<harmony>
<root>
<root-step>A</root-step>
</root>
<kind text="7">dominant</kind>
<inversion>3</inversion>
<bass>
<bass-step>G</bass-step>
</bass>
</harmony>
'''
figure = 'A7/G'
pitches = ('G2', 'A2', 'C#3', 'E3')
self.runTestOnChord(xmlString, figure, pitches)
def testChordFlatSharpInFigure(self):
# Octave placement of this A2 neither great nor intolerable
pitches = ('G2', 'A2', 'B2', 'D#3', 'F3')
figure = 'G+9'
cs = ChordSymbol(figure)
self.assertEqual(cs.pitches, tuple(pitch.Pitch(p) for p in pitches))
pitches = ('G2', 'B2', 'D#3', 'F3', 'A3')
figure = 'G9#5'
cs = ChordSymbol(figure)
self.assertEqual(cs.pitches, tuple(pitch.Pitch(p) for p in pitches))
pitches = ('A2', 'C3', 'E3', 'G#3')
pitches = tuple(pitch.Pitch(p) for p in pitches)
self.assertEqual(pitches, ChordSymbol('AmM7').pitches)
self.assertEqual(pitches, ChordSymbol('Aminmaj7').pitches)
pitches = ('A1', 'C2', 'E2', 'G#3')
pitches = tuple(pitch.Pitch(p) for p in pitches)
self.assertEqual(pitches, ChordSymbol('Am#7').pitches)
pitches = ('C2', 'F2', 'G2', 'B-3')
pitches = tuple(pitch.Pitch(p) for p in pitches)
self.assertEqual(pitches, ChordSymbol('Csusaddb7').pitches)
def testRootBassParsing(self):
'''
This tests a bug where the root and bass were wrongly parsed,
since the matched root and bass were globally removed from figure,
and not only where matched.
'''
xmlString = '''
<harmony>
<root>
<root-step>E</root-step>
</root>
<kind text="7">dominant</kind>
<bass>
<bass-step>E</bass-step>
<bass-alter>-1</bass-alter>
</bass>
</harmony>
'''
figure = 'E7/E-'
pitches = ('E-2', 'E3', 'G#3', 'B3', 'D4')
self.runTestOnChord(xmlString, figure, pitches)
def testChordStepBass(self):
'''
This tests a bug where the chord modification (add 2) was placed at a
wrong octave, resulting in a D bass instead of the proper E.
'''
xmlString = '''
<harmony>
<root>
<root-step>C</root-step>
</root>
<kind>major</kind>
<bass>
<bass-step>E</bass-step>
</bass>
<degree>
<degree-value>2</degree-value>
<degree-alter>0</degree-alter>
<degree-type text="add">add</degree-type>
</degree>
</harmony>
'''
figure = 'C/E add 2'
pitches = ('E3', 'G3', 'C4', 'D4')
self.runTestOnChord(xmlString, figure, pitches)
def testSusBass(self):
'''
This tests a bug where the bass addition was considered as the fifth
inversion in suspended chords. Now, this is considered as a non-valid
inversion, and the bass is simply added before the root.
'''
from xml.etree.ElementTree import fromstring as EL
from music21 import musicxml
pitches = ('G2', 'D3', 'G3', 'A3')
pitches = tuple(pitch.Pitch(p) for p in pitches)
xmlString = '''
<harmony>
<root>
<root-step>D</root-step>
</root>
<kind text="sus">suspended-fourth</kind>
<bass>
<bass-step>G</bass-step>
</bass>
</harmony>
'''
MP = musicxml.xmlToM21.MeasureParser()
mxHarmony = EL(xmlString)
cs1 = MP.xmlToChordSymbol(mxHarmony)
cs2 = ChordSymbol(cs1.figure)
cs3 = ChordSymbol('Dsus/G')
self.assertEqual(pitches, cs1.pitches)
self.assertEqual(pitches, cs2.pitches)
self.assertEqual(pitches, cs3.pitches)
def testBassNotInChord(self):
from xml.etree.ElementTree import fromstring as EL
from music21 import musicxml
pitches = ('E-3', 'E3', 'G3', 'C4')
pitches = tuple(pitch.Pitch(p) for p in pitches)
xmlString = '''
<harmony>
<root>
<root-step>C</root-step>
</root>
<kind text="">major</kind>
<bass>
<bass-step>E-</bass-step>
</bass>
</harmony>
'''
MP = musicxml.xmlToM21.MeasureParser()
mxHarmony = EL(xmlString)
cs1 = MP.xmlToChordSymbol(mxHarmony)
cs2 = ChordSymbol(cs1.figure)
cs3 = ChordSymbol('C/E-')
self.assertEqual(pitches, cs1.pitches)
self.assertEqual(pitches, cs2.pitches)
self.assertEqual(pitches, cs3.pitches)
# There was a bug where the bass was E3, because E-3 was assumed to be
# in the chord.
self.assertEqual('E-3', cs1.bass().nameWithOctave)
def testSus2Bass(self):
from xml.etree.ElementTree import fromstring as EL
from music21 import musicxml
pitches = ('E3', 'G3', 'C4', 'D4')
pitches = tuple(pitch.Pitch(p) for p in pitches)
xmlString = '''
<harmony>
<root>
<root-step>C</root-step>
</root>
<kind text="sus2">suspended-second</kind>
<bass>
<bass-step>E</bass-step>
</bass>
</harmony>
'''
MP = musicxml.xmlToM21.MeasureParser()
mxHarmony = EL(xmlString)
cs1 = MP.xmlToChordSymbol(mxHarmony)
cs2 = ChordSymbol(cs1.figure)
cs3 = ChordSymbol('Csus2/E')
self.assertEqual('E3', cs1.bass().nameWithOctave)
self.assertEqual(pitches, cs1.pitches)
self.assertEqual(pitches, cs2.pitches)
self.assertEqual(pitches, cs3.pitches)
def testNinth(self):
'''
This tests a bug in _adjustOctaves.
'''
xmlString = '''
<harmony >
<root>
<root-step>D</root-step>
</root>
<kind text="min9">minor-ninth</kind>
</harmony>
'''
pitches = ('D2', 'F2', 'A2', 'C3', 'E3')
figure = 'Dm9'
self.runTestOnChord(xmlString, figure, pitches)
def testInversion(self):
from xml.etree.ElementTree import fromstring as EL
from music21 import musicxml
xmlString = '''
<harmony>
<root>
<root-step>C</root-step>
</root>
<kind>major</kind>
<inversion>1</inversion>
</harmony>
'''
pitches = ('E2', 'G2', 'C3')
pitches = tuple(pitch.Pitch(p) for p in pitches)
MP = musicxml.xmlToM21.MeasureParser()
mxHarmony = EL(xmlString)
cs1 = MP.xmlToChordSymbol(mxHarmony)
cs2 = ChordSymbol('C/E')
self.assertEqual(1, cs1.inversion())
self.assertEqual(1, cs2.inversion())
pitches = ('E3', 'G3', 'C4')
pitches = tuple(pitch.Pitch(p) for p in pitches)
self.assertEqual(cs1.pitches, pitches)
self.assertEqual(cs2.pitches, pitches)
self.assertEqual(cs1.root(), cs2.root())
self.assertEqual(cs1.bass(), cs2.bass())
def testChordWithoutKind(self):
cs = ChordSymbol(root='C', bass='E')
self.assertEqual(1, cs.inversion())
self.assertEqual('C4', str(cs.root()))
self.assertEqual('E3', str(cs.bass()))
def testChordStepFromFigure(self):
xmlString = '''
<harmony>
<root>
<root-step>G</root-step>
</root>
<kind text="7alt">dominant</kind>
<degree>
<degree-value>5</degree-value>
<degree-alter>0</degree-alter>
<degree-type>subtract</degree-type>
</degree>
<degree>
<degree-value>9</degree-value>
<degree-alter>-1</degree-alter>
<degree-type>add</degree-type>
</degree>
<degree>
<degree-value>9</degree-value>
<degree-alter>1</degree-alter>
<degree-type>add</degree-type>
</degree>
<degree>
<degree-value>11</degree-value>
<degree-alter>1</degree-alter>
<degree-type>add</degree-type>
</degree>
<degree>
<degree-value>13</degree-value>
<degree-alter>-1</degree-alter>
<degree-type>add</degree-type>
</degree>
</harmony>
'''
figure = 'G7 subtract 5 add b9 add #9 add #11 add b13'
pitches = ('G2', 'B2', 'F3', 'A-3', 'A#3', 'C#4', 'E-4')
self.runTestOnChord(xmlString, figure, pitches)
figure = 'G7 subtract5 addb9 add#9 add#11 addb13'
self.runTestOnChord(xmlString, figure, pitches)
figure = 'G7subtract5addb9add#9add#11addb13'
self.runTestOnChord(xmlString, figure, pitches)
#########
xmlString = '''
<harmony>
<root>
<root-step>C</root-step>
</root>
<kind text="7b9">dominant</kind>
<degree>
<degree-value>9</degree-value>
<degree-alter>-1</degree-alter>
<degree-type>add</degree-type>
</degree>
</harmony>
'''
figure = 'C7 b9'
pitches = ('C3', 'E3', 'G3', 'B-3', 'D-4')
self.runTestOnChord(xmlString, figure, pitches)
figure = 'C7 add b9'
self.runTestOnChord(xmlString, figure, pitches)
# Test alter
cs = ChordSymbol('A7 alter #5')
self.assertEqual('(<music21.pitch.Pitch A2>, <music21.pitch.Pitch '
'C#3>, <music21.pitch.Pitch E#3>, '
'<music21.pitch.Pitch G3>)', str(cs.pitches))
#########
xmlString = '''
<harmony>
<root>
<root-step>A</root-step>
</root>
<kind>dominant</kind>
<degree>
<degree-value>5</degree-value>
<degree-alter>1</degree-alter>
<degree-type>alter</degree-type>
</degree>
<degree>
<degree-value>9</degree-value>
<degree-alter>1</degree-alter>
<degree-type>add</degree-type>
</degree>
<degree>
<degree-value>11</degree-value>
<degree-alter>1</degree-alter>
<degree-type>add</degree-type>
</degree>
</harmony>
'''
figure = 'A7 alter #5 add #9 add #11'
pitches = ('A2', 'C#3', 'E#3', 'G3', 'B#3', 'D#4')
self.runTestOnChord(xmlString, figure, pitches)
def testExpressSusUsingAlterations(self):
ch1 = ChordSymbol('F7 add 4 subtract 3')
ch2 = ChordSymbol('F7sus4')
self.assertEqual(ch1.pitches, ch2.pitches)
def testDoubledCharacters(self):
ch1 = ChordSymbol('Co omit5')
ch2 = ChordSymbol('Cdim omit5')
self.assertEqual(ch1.pitches, ch2.pitches)
def x_testPower(self):
'''
Power chords should not have inversions.
'''
pitches = ('E2', 'A2', 'E3')
pitches = tuple(pitch.Pitch(p) for p in pitches)
xmlString = '''
<harmony>
<root>
<root-step>A</root-step>
</root>
<kind text="5">power</kind>
<bass>
<bass-step>E</bass-step>
</bass>
</harmony>
'''
figure = 'Apower/E'
self.runTestOnChord(xmlString, figure, pitches)
def testSingleChordSymbol(self):
'''
Test an edge case where a Stream contains only one ChordSymbol
at the highest offset: should still have a nonzero duration
if there is a subsequent highest time.
'''
from music21 import note
from music21 import stream
m = stream.Measure() # NB: no barline!
cs = ChordSymbol('A7')
m.insert(0, note.Note(type='whole'))
m.insert(1.0, cs)
realizeChordSymbolDurations(m)
self.assertEqual(cs.quarterLength, 3.0)
def testUpdatePitchesFalse(self):
bass_note = pitch.Pitch('C3')
h = Harmony(bass=bass_note, updatePitches=False)
# No other pitches are created
self.assertEqual(h.pitches, (bass_note,))
class TestExternal(unittest.TestCase):
def testReadInXML(self):
from music21 import harmony
from music21 import corpus
from music21 import stream
testFile = corpus.parse('leadSheet/fosterBrownHair.xml')
# testFile.show('text')
testFile = harmony.realizeChordSymbolDurations(testFile)
# testFile.show()
chordSymbols = testFile.flatten().getElementsByClass(harmony.ChordSymbol)
s = stream.Stream()
for cS in chordSymbols:
cS.writeAsChord = False
s.append(cS)
# csChords = s.flatten().getElementsByClass(chord.Chord)
# s.show()
# self.assertEqual(len(csChords), 40)
def testChordRealization(self):
from music21 import harmony
from music21 import corpus
from music21 import note
from music21 import stream
# There is a test file under demos called ComprehensiveChordSymbolsTestFile.xml
# that should contain a complete iteration of tests of chord symbol objects
# this test makes sure that no error exists, and checks that 57 chords were
# created out of that file. Feel free to add to file if you find missing
# tests, and adjust 57 accordingly
testFile = corpus.parse('demos/ComprehensiveChordSymbolsTestFile.xml')
testFile = harmony.realizeChordSymbolDurations(testFile)
chords = testFile.flatten().getElementsByClass(harmony.ChordSymbol)
# testFile.show()
s = stream.Stream()
# i = 0
for x in chords:
# print(x.pitches)
x.quarterLength = 0
s.insert(x.offset, x)
# i += 4
#
# x.show()
s.makeRests(fillGaps=True, inPlace=True)
s.append(note.Rest(quarterLength=4))
unused_csChords = s.flatten().getElementsByClass(chord.Chord)
# self.assertEqual(len(csChords), 57)
# s.show()
# s.show('text')
def testALLChordKinds(self):
notes = ['A', 'B', 'C', 'D', 'E', 'F', 'G']
mod = ['', '-', '#']
for n in notes:
for m in mod:
for unused_key, val in CHORD_TYPES.items():
# example val = ['1,-3,5,6', ['m6', 'min6']]
for harmony_type in val[1]:
symbol = n + m + harmony_type
ChordSymbol(symbol)
# def labelChordSymbols(self):
# '''
# A very rough sketch of code to label the chord symbols in a bach
# chorale (in response to a post to the music21 list asking if this is
# possible).
# '''
# from music21.alpha.theoryAnalysis import theoryAnalyzer
# from music21 import harmony, corpus
#
# score = corpus.parse('bach/bwv380')
# excerpt = score.measures(2, 3)
#
# # remove passing and/or neighbor tones?
# analyzer = theoryAnalyzer.Analyzer()
# analyzer.removePassingTones(excerpt)
# analyzer.removeNeighborTones(excerpt)
#
# slices = analyzer.getVerticalities(excerpt)
# for vs in slices:
# x = harmony.chordSymbolFigureFromChord(vs.getChord())
# if x != 'Chord Symbol Cannot Be Identified':
# vs.lyric = x.replace('-', 'b')
# print(x.replace('-', 'b'))
# ------------------------------------------------------------------------------
_DOC_ORDER = [Harmony, chordSymbolFigureFromChord, ChordSymbol, ChordStepModification]
if __name__ == '__main__':
import music21
music21.mainTest(Test) # , runTest='testChordStepBass')