Revamp

generator/solo/gesture_rhythm.py

@@ -14,9 +14,45 @@ def fragmentation(notes):
   return isolated + .1*gaps
 
 
+def shared_arrival(draft,harmony,treatments=()):
+  """A provisional endpoint may also begin a continuation, without reattack.
+
+  Retain the continuation event's identity. A rhythm/exact-quote contract or
+  a committed destination can forbid sharing; full context is revalidated.
+  """
+  notes=draft.notes
+  joins={t.start for t in draft.transformations[1:] if t.operation=='continue'}
+  fixed=set(draft.protected)|set(draft.structural)
+  fixed.update(n.event_id for n in notes if n.role=='quote')
+  fixed.update(e for f in draft.features if 'rhythm' in f.preserves for e in f.events)
+  edits=[]
+  for join in sorted(joins):
+    for i,(a,b) in enumerate(zip(notes,notes[1:])):
+      if b.start!=join or a.end!=b.start or a.pitch!=b.pitch:continue
+      if a.event_id in fixed or b.event_id in fixed:continue
+      actual=(*notes[:i],dataclasses.replace(b,start=a.start),*notes[i+2:])
+      if not drafts.contract_valid(draft,actual)[0]:continue
+      if not harmony.evaluate(actual,treatments,until=draft.end,complete=True).valid:continue
+      if not harmonic.anchors_valid(draft.anchors,actual,draft.end,complete=True,closure='closed')[0]:continue
+      edits.append(types.DraftEdit('shared_arrival',a.start,b.end,(a.event_id,b.event_id),(b.event_id,),
+        'reopen provisional endpoint as the same sounding continuation; preserve feature and arrival contracts'))
+      notes=actual
+      break
+  if not edits:return draft,()
+  by_id={n.event_id:n for n in notes}
+  transforms=[]
+  for t in draft.transformations:
+    group=tuple(by_id[e] for e in t.events if e in by_id)
+    if group:
+      transforms.append(dataclasses.replace(t,start=group[0].start,end=group[-1].end,
+        events=tuple(n.event_id for n in group),rhythm=tuple((n.start-group[0].start,n.end-group[0].start) for n in group)))
+  return dataclasses.replace(draft,notes=notes,transformations=tuple(transforms)),tuple(edits)
+
+
 def revise(draft, harmony, treatments=()):
-  notes=draft.notes; edits=[]
-  if len(notes)<3: return draft, ()
+  draft,shared=shared_arrival(draft,harmony,treatments)
+  notes=draft.notes; edits=list(shared)
+  if len(notes)<3: return draft, tuple(edits)
   protected=set(draft.protected)|set(draft.structural)|{n.event_id for n in notes if n.role=='quote'}
   # An identifying rhythm also protects its internal rests.
   protected.update(e for feature in draft.features if 'rhythm' in feature.preserves for e in feature.events)