chords.py

#! python3

from interval import get_interval, INTERVAL

def get_triad(bass, figure=''):
    '''takes a bass note (ie a,b,c,d ...) and a figured bass string (ie '6/4', '6')'''
    n1 = bass
    n2 = ''
    n3 = ''
    if figure == '':
        n2 = get_interval(bass, INTERVAL['M3'])
        n3 = get_interval(bass, INTERVAL['P5'])
    elif figure == '6':
        n2 = get_interval(bass, INTERVAL['m3'])
        n3 = get_interval(bass, INTERVAL['m6'])
    elif figure == '6/4':
        n2 = get_interval(bass, INTERVAL['P4'])
        n3 = get_interval(bass, INTERVAL['M6'])
    return '< {} {} {} >'.format(n1,n2,n3)

if __name__ == "__main__":
    assert get_triad('c') == '< c e g >'
    print(get_triad('f','6'))
    assert get_triad('f', '6') == '< f aes des >'
    assert get_triad('des') == '< des f aes >'