Source code for pychord.progression

from typing import Union, List

from .chord import Chord


[docs]class ChordProgression: """ Class to handle chord progressions. Attributes: _chords: component chords of chord progression. """ def __init__(self, initial_chords: Union[str, Chord, List[Union[str, Chord]]] = None): """ Constructor of ChordProgression instance. :param initial_chords: Initial chord or chords of the chord progressions """ if initial_chords is None: initial_chords = [] if isinstance(initial_chords, Chord): chords = [initial_chords] elif isinstance(initial_chords, str): chords = [self._as_chord(initial_chords)] elif isinstance(initial_chords, list): chords = [self._as_chord(chord) for chord in initial_chords] else: raise TypeError(f"Cannot initialize ChordProgression with argument of {type(initial_chords)} type") self._chords: List[Chord] = chords def __unicode__(self): return " | ".join([chord.chord for chord in self._chords]) def __str__(self): return " | ".join([chord.chord for chord in self._chords]) def __repr__(self): return f"<ChordProgression: {' | '.join([chord.chord for chord in self._chords])}>" def __add__(self, other): self._chords += other.chords return self def __len__(self): return len(self._chords) def __getitem__(self, item): return self._chords[item] def __setitem__(self, key, value): self._chords[key] = value def __eq__(self, other): if not isinstance(other, ChordProgression): raise TypeError(f"Cannot compare ChordProgression object with {type(other)} object") if len(self) != len(other): return False for c, o in zip(self, other): if c != o: return False return True def __ne__(self, other): return not self.__eq__(other) @property def chords(self) -> List[Chord]: """ Get component chords of chord progression """ return self._chords
[docs] def append(self, chord: Union[str, Chord]) -> None: """ Append a chord to chord progressions :param chord: A chord to append """ self._chords.append(self._as_chord(chord))
[docs] def insert(self, index: int, chord: Union[str, Chord]) -> None: """ Insert a chord to chord progressions :param index: Index to insert a chord :param chord: A chord to insert """ self._chords.insert(index, self._as_chord(chord))
[docs] def pop(self, index: int = -1) -> Chord: """ Pop a chord from chord progressions :param index: Index of the chord to pop (default: -1) """ return self._chords.pop(index)
[docs] def transpose(self, trans: int) -> None: """ Transpose whole chord progressions :param trans: Transpose key """ for chord in self._chords: chord.transpose(trans)
@staticmethod def _as_chord(chord: Union[str, Chord]) -> Chord: """ Convert from str to Chord instance if input is str :param chord: Chord name or Chord instance :return: Chord instance """ if isinstance(chord, Chord): return chord elif isinstance(chord, str): return Chord(chord) else: raise TypeError("input type should be str or Chord instance.")