Rhythm Comping Pairs

generator/acoustic.py

@@ -110,10 +110,10 @@ def combine(document: dict) -> None:
       b = fragments[end][0] if end in fragments else originals[end]
       a['tie_to'], b['tie_from'] = b['id'], a['id']
 
-def validate_comping(document: dict) -> None:
-  """Check complete sounding events, not barline or notation fragments."""
+def sounding_lanes(measures):
+  """Recover complete string-lane events, preserving ties versus reattacks."""
   tones, starts, cursor = {}, {}, fractions.Fraction()
-  for measure in document['staves'][0]['measures']:
+  for measure in measures:
     for note in generator.score.measure_notes(measure):
       for pitch in note['pitches']:
         tones[pitch['id']] = pitch
@@ -122,6 +122,8 @@ def validate_comping(document: dict) -> None:
   groups = {}
   for identifier, pitch in tones.items():
     if pitch.get('tie_from') in tones:
+      if tones[pitch['tie_from']].get('tie_to') != identifier:
+        raise ValueError('broken acoustic sustain link')
       continue
     start, tail = starts[identifier], pitch
     seen = {identifier}
@@ -129,20 +131,35 @@ def validate_comping(document: dict) -> None:
       target = tail['tie_to']
       if target in seen:
         raise ValueError('cyclic acoustic sustain')
+      continuation = tones[target]
+      if continuation.get('tie_from') != tail['id'] or starts[target] != starts[tail['id']] + generator.model.fraction(tail['duration']):
+        raise ValueError('broken acoustic sustain link or timing')
+      if generator.model.pitch_number(continuation) != generator.model.pitch_number(tail) or continuation.get('tablature') != tail.get('tablature'):
+        raise ValueError('acoustic sustain changes pitch or position')
       seen.add(target)
-      tail = tones[target]
+      tail = continuation
     end = starts[tail['id']] + generator.model.fraction(tail['duration'])
     string = pitch.get('tablature', {}).get('string')
     if string is None:
       raise ValueError('acoustic comping requires placed notes')
     groups.setdefault((start, end), set()).add('bass' if string >= 5 else 'upper')
+  return groups
+
+def validate_assignment(measures, events):
+  expected = {}
+  for e in events:
+    lanes = ['bass', 'upper'] if e.lane == 'combined' else [e.lane]
+    expected.setdefault((e.start, e.end), set()).update(lanes)
+  if sounding_lanes(measures) != expected:
+    raise ValueError('rendered acoustic attacks disagree with the selected bass/upper assignment')
+
+def validate_comping(document: dict) -> None:
+  """Check complete sounding events, not barline or notation fragments."""
+  groups = sounding_lanes(document['staves'][0]['measures'])
   events = []
   for (start, end), lanes in groups.items():
-    if len(lanes) == 2:
-      if end - start < 1 and end - start != fractions.Fraction(1, 2):
-        raise ValueError('combined acoustic attacks require quarter/eighth notes or sustains')
-    elif end - start not in (fractions.Fraction(1, 2), 1):
-      raise ValueError('separate acoustic comping requires quarter/eighth notes')
+    if end <= start or (end - start < 1 and end - start != fractions.Fraction(1, 2)):
+      raise ValueError('acoustic comping requires quarter/eighth notes or authored sustains')
     events.append((start, end))
   events.sort()
   # Distinct lanes can overlap. The physical validator still checks sounding