Function determine_polychords

mingus/core/chords.py:1299–1337

Determine the polychords in chord. This function can handle anything from polychords based on two triads to 6 note extended chords.

(chord, shorthand=False)

def determine_polychords(chord, shorthand=False):
    """Determine the polychords in chord.
    
    This function can handle anything from polychords based on two triads to
    6 note extended chords.
    """
    polychords = []
    function_list = [
        determine_triad,
        determine_seventh,
        determine_extended_chord5,
        determine_extended_chord6,
        determine_extended_chord7,
    ]

    # Range tracking.
    if len(chord) <= 3:
        return []
    elif len(chord) > 14:
        return []
    elif len(chord) - 3 <= 5:
        function_nr = list(range(0, len(chord) - 3))
    else:
        function_nr = list(range(0, 5))
    for f in function_nr:
        for f2 in function_nr:
            # The clever part: Try the function_list[f] on the len(chord) - (3 +
            # f) last notes of the chord. Then try the function_list[f2] on the
            # f2 + 3 first notes of the chord. Thus, trying all possible
            # combinations.
            for chord1 in function_list[f](
                chord[len(chord) - (3 + f) :], True, True, True
            ):
                for chord2 in function_list[f2](chord[: f2 + 3], True, True, True):
                    polychords.append("%s|%s" % (chord1, chord2))
    if shorthand:
        for p in polychords:
            p = p + " polychord"
    return polychords


# A dictionairy that can be used to present chord abbreviations. This