adding magic methods call, len and getitem for MIDITokenizer

miditok/midi_tokenizer_base.py

@@ -86,7 +86,7 @@ def __init__(self, pitch_range: range, beat_res: Dict[Tuple[int, int], int], nb_
         # MIDI (being parsed) so that methods processing tracks can access them
         self.current_midi_metadata = {}  # needs to be updated each time a MIDI is read
 
-    def midi_to_tokens(self, midi: MidiFile) -> List[List[Union[int, List[int]]]]:
+    def midi_to_tokens(self, midi: MidiFile, *args, **kwargs) -> List[List[Union[int, List[int]]]]:
         """ Converts a MIDI file in a tokens representation.
         NOTE: if you override this method, be sure to keep the first lines in your method
 
@@ -608,6 +608,22 @@ def load_params(self, params: Union[str, Path, PurePath, Dict[str, Any]]):
         if '_mask' not in params:
             self._mask = False
 
+    def __call__(self, midi: MidiFile, *args, **kwargs):
+        return self.midi_to_tokens(midi, *args, **kwargs)
+
+    def __len__(self):
+        return [len(v) for v in self.vocab] if isinstance(self.vocab, list) else len(self.vocab)
+
+    def __getitem__(self, item: Union[int, str, Tuple[int, int]]) -> Union[str, int]:
+        if isinstance(item, str):
+            return self.vocab.event_to_token[item]
+        elif isinstance(item, int):
+            return self.vocab.token_to_event[item]
+        elif isinstance(item, tuple) and isinstance(self.vocab, list):
+            return self.vocab[item[0]].token_to_event[item[1]]
+        else:
+            raise IndexError('The index must be an integer or a string')
+
 
 def get_midi_programs(midi: MidiFile) -> List[Tuple[int, bool]]:
     """ Returns the list of programs of the tracks of a MIDI, deeping the