from .constants import CHORD_MATCHER
from .mixins import Aug
from .mixins import Dim
from .mixins import OctaveMixin
from .notes import Note
from .notes import NoteGroupBase
from .scales import Dorian
from .scales import HalfWholeDiminished
from .scales import HarmonicMinor
from .scales import Ionian
from .scales import Lydian
from .scales import Mixolydian
from .scales import WholeHalfDiminished
# References:
# - http://www.cs.cmu.edu/~scottd/chords_and_scales/music.html
# - https://en.wikipedia.org/wiki/List_of_chords
# The CHORD_MAP is a dictionary where the chord name is mapped to a list of
# shorthand notations and the corresponding transpose list to create the
# chord given a root note. The shorthand list order is not consequential
# except that when producing all the chords the first element in the list
# is chosen as the desired shorthand notation.
CHORD_MAP = {
# Triads
'major_triad': {'shorthand': ['M', '', 'maj', 'ma', 'major'],
'scale': Ionian,
'transpose_list': [0, 4, 7]},
'minor_triad': {'shorthand': ['m', 'min', 'mi', '-', 'minor'],
'scale': Dorian,
'transpose_list': [0, 3, 7]},
# Augmented
'augmented_triad': {'shorthand': ['aug', '+'],
'transpose_list': [0, 4, Aug(7)]},
'augmented_major_seventh': {'shorthand': ['M7+', 'augM7'],
'transpose_list': [0, 4, Aug(7), 'e']},
'augmented_minor_seventh': {'shorthand': ['m7+', 'augm7'],
'transpose_list': [0, 4, Aug(7), 't']},
'lydian_dominant_seventh': {'shorthand': ['7#11'],
'scale': Lydian,
'transpose_list': [0, 4, 7, 't', Aug(17)]},
# Diminished
'diminished_major_seventh': {'shorthand': ['dimM7', 'M7o'],
'scale': WholeHalfDiminished,
'transpose_list': [0, 3, 6, 'e']},
'diminished_seventh': {'shorthand': ['dim7', '7o'],
'scale': WholeHalfDiminished,
'transpose_list': [0, 3, 6, Dim(10)]},
'diminished_triad': {'shorthand': ['dim', 'o'],
'scale': WholeHalfDiminished,
'transpose_list': [0, 3, 6]},
# Fifths
'major_fifth': {'shorthand': ['5'],
'transpose_list': [0, 7]},
# Sixths
'major_sixth': {'shorthand': ['M6', '6', 'maj6'],
'scale': Ionian,
'transpose_list': [0, 4, 7, 9]},
'minor_sixth': {'shorthand': ['m6', 'min6'],
'scale': Dorian,
'transpose_list': [0, 3, 7, 9]},
'sixth_ninth': {'shorthand': ['69', '6/9'],
'scale': Ionian,
'transpose_list': [0, 4, 7, 9, 14]},
'dominant_sixth': {'shorthand': ['67'],
'transpose_list': [0, 4, 7, 9, 10]},
# Sevenths
'dominant_seventh': {'shorthand': ['7'],
'scale': Mixolydian,
'transpose_list': [0, 4, 7, 10]},
'major_seventh': {'shorthand': ['M7', 'maj7', 'ma7'], # delta7 and delta
'scale': Ionian,
'transpose_list': [0, 4, 7, 11]},
'major_seventh_sharp_five': {'shorthand': ['M7#5', 'M7+5'],
'transpose_list': [0, 4, 8, 11]},
'major_seventh_flat_five': {'shorthand': ['M7b5', 'M7-5'],
'transpose_list': [0, 4, 6, 11]},
'minor_major_seventh': {'shorthand': ['mM7', 'm/M7', 'm/maj7'],
'scale': HarmonicMinor,
'transpose_list': [0, 3, 7, 11]},
'minor_seventh': {'shorthand': ['m7', 'min7', 'mi7', '-7'],
'scale': Dorian,
'transpose_list': [0, 3, 7, 10]},
'minor_seventh_sharp_five': {'shorthand': ['m7#5', 'm7+5'],
'transpose_list': [0, 3, 8, 10]},
'minor_seventh_flat_five': {'shorthand': ['m7b5', 'm7-5'],
'transpose_list': [0, 3, 6, 10]},
# Ninths
'added_ninth': {'shorthand': ['add9'],
'transpose_list': [0, 4, 7, 14]},
'minor_added_ninth': {'shorthand': ['madd9'],
'transpose_list': [0, 3, 7, 14]},
'dominant_ninth': {'shorthand': ['9'],
'scale': Mixolydian,
'transpose_list': [0, 4, 7, 10, 14]},
'dominant_ninth_flat_five': {'shorthand': ['9b5', '9-5'],
'transpose_list': [0, 4, 6, 10, 14]},
'dominant_ninth_sharp_five': {'shorthand': ['9#5', '9+5'],
'transpose_list': [0, 4, 8, 10, 14]},
'dominant_flat_ninth': {'shorthand': ['7b9', '7-9'],
'scale': HalfWholeDiminished,
'transpose_list': [0, 4, 7, 10, 13]},
'dominant_sharp_ninth': {'shorthand': ['7#9', '7+9'],
'scale': Mixolydian, # with flat 3rd
'transpose_list': [0, 4, 7, 10, Aug(14)]},
'dominant_sharp_ninth_flat_five': {'shorthand': ['7#9b5', '7+9-5'],
'transpose_list': [0, 4, 6, 10,
Aug(14)]},
'major_ninth': {'shorthand': ['M9', 'maj9', 'ma9'],
'scale': Ionian,
'transpose_list': [0, 4, 7, 11, 14]},
'minor_ninth': {'shorthand': ['m9', 'min9', 'mi9'],
'scale': Dorian,
'transpose_list': [0, 3, 7, 10, 14]},
'minor_ninth_flat_five': {'shorthand': ['m9b5', 'm9-5'],
'transpose_list': [0, 3, 6, 10, 14]},
# Elevenths
'eleventh': {'shorthand': ['11'],
'scale': Mixolydian,
'transpose_list': [0, 7, 10, 17]},
'minor_eleventh': {'shorthand': ['m11'],
'scale': Dorian,
'transpose_list': [0, 3, 7, 10, 17]},
# Thirteenths
'dominant_thirteenth': {'shorthand': ['13'],
'scale': Mixolydian,
'transpose_list': [0, 4, 7, 10, 14, 21]},
'major_thirteenth': {'shorthand': ['M13', 'maj13'],
'scale': Ionian,
'transpose_list': [0, 4, 7, 11, 14, 21]},
'minor_thirteenth': {'shorthand': ['m13'],
'scale': Dorian,
'transpose_list': [0, 3, 7, 10, 14, 21]},
# Altered
'dominant_flat_five': {'shorthand': ['7b5', '7-5'],
'transpose_list': [0, 4, 6, 't']},
'dominant_sharp_five': {'shorthand': ['7#5', '7+5'],
'transpose_list': [0, 4, 8, 't']},
# Atonal
'ode_to_napoleon': {'shorthand': ['napoleon'],
'transpose_list': [0, 1, 4, 5, 8, 9]},
'farben': {'shorthand': ['farben'],
'transpose_list': [0, 8, 'e', 16, 21]},
'mystic': {'shorthand': ['mystic'],
'transpose_list': [0, 6, 't', 16, 21, 26]},
'northern_lights': {'shorthand': ['northern'],
'transpose_list': [1, 2, 8, 12, 15, 18,
19, 22, 23, 28, 31]},
'viennese_trichord': {'shorthand': ['viennese'],
'transpose_list': [0, 1, 6]},
# Bitonal
'elektra': {'shorthand': ['elektra'],
'transpose_list': [0, 7, 9, 13, 16]},
'so_what': {'shorthand': ['so_what'],
'transpose_list': [0, 5, 't', 15, 19]},
# Mixed
'hendrix_chord': {'shorthand': ['7b12', 'hendrix'],
'transpose_list': [0, 4, 7, 't', 15]},
'petrushka': {'shorthand': ['petrushka'],
'transpose_list': [0, 1, 4, 6, 7, 't']},
# Predominant
'augmented_sixth': {'shorthand': ['aug6'],
'transpose_list': [0, 6, 8]},
'tristan': {'shorthand': ['tristan'],
'transpose_list': [0, 3, 6, 't']},
# Suspended
'suspended_fourth_ninth': {'shorthand': ['sus4b9'],
'transpose_list': [0, 5, 7, 13]},
'suspended_fourth_triad': {'shorthand': ['sus4', 'sus'],
'scale': Mixolydian,
'transpose_list': [0, 5, 7]},
'suspended_second_triad': {'shorthand': ['sus2'],
'scale': Mixolydian,
'transpose_list': [0, 2, 7]},
'suspended_seventh': {'shorthand': ['sus47', '7sus4'],
'scale': Mixolydian,
'transpose_list': [0, 5, 7, 't']},
}
SHORTHAND_TO_TRANSPOSE = {}
SHORTHAND_TO_SCALE = {}
for name, data in CHORD_MAP.items():
for short in data['shorthand']:
SHORTHAND_TO_TRANSPOSE[short] = data.get('transpose_list', [])
SHORTHAND_TO_SCALE[short] = data.get('scale', None)
[docs]class Chord(NoteGroupBase, OctaveMixin):
"""
Source Material: https://en.wikipedia.org/wiki/Chord_(music)
"""
def __init__(self, chord=None, octave=None):
"""
Create chords from a chord name and an optional octave.
"""
self._octave = octave
if isinstance(chord, str):
self._set_from_string(chord)
else:
raise Exception('Must instantiate Chord() object with a '
'chord name')
def __str__(self):
return '{0}{1}'.format(self.root.generalize() if self.notes else '',
self.extension)
def __repr__(self):
rep_str = "{0}('{1}'".format(type(self).__name__, str(self))
if self._octave:
rep_str = "{0}, octave={1}".format(rep_str, self._octave)
return "{0})".format(rep_str)
def __eq__(self, other):
# Chords must be of the same class or derived from the Chord class
if not (isinstance(other, self.__class__) or isinstance(other, Chord)):
return False
if self.__dict__ == other.__dict__:
return True
# Scales are identical if their generic notes are also identical
if self.notes == other.notes:
return True
return False
def _set_from_string(self, chord):
m = CHORD_MATCHER.match(chord)
if m is None:
raise Exception("Unknown chord format: {0}".format(chord))
root, self.extension = m.group(1), m.group(2)
if self._octave:
root = "{0}{1}".format(root, self._octave)
self.intervals = self._get_intervals(self.extension)
self.scale_cls = self._get_scale_cls(self.extension)
self.root = Note(root)
self.notes = self.root.transpose_list(self.intervals)
@classmethod
def _get_intervals(cls, shorthand):
"""
Given shorthand extension return the list of intervals to transpose
"""
if shorthand not in SHORTHAND_TO_TRANSPOSE:
raise Exception("Unknown chord extensions: {0}".format(shorthand))
return SHORTHAND_TO_TRANSPOSE[shorthand]
@classmethod
def _get_scale_cls(cls, shorthand):
"""
Given shorthand extension return the Scale class associated with it
"""
if shorthand not in SHORTHAND_TO_SCALE:
raise Exception("Unknown chord extensions: {0}".format(shorthand))
return SHORTHAND_TO_SCALE[shorthand]
[docs] def get_scale(self):
if self.scale_cls:
return self.scale_cls(self.root)
return self.scale_cls
def produce_all_chords(root):
"""
Produce all chords given a root note.
Returns a dictionary of chord names as the key and the chord object
as the value.
"""
chord_info = {}
for name, data in CHORD_MAP.items():
shorthand = data['shorthand'][0]
chord_name = '{0}{1}'.format(root, shorthand)
chord = Chord(chord_name)
chord_info[name] = chord
return chord_info