Soloing

generator/solo/composer.py

@@ -0,0 +1,58 @@
+from __future__ import annotations
+
+import dataclasses
+import fractions
+
+import generator.fretboard
+import generator.harmony
+import generator.model
+import generator.scales.selection
+import generator.scales.timeline
+import generator.solo.analysis
+import generator.solo.planning
+import generator.solo.realization
+import generator.solo.types
+
+def compose(analysis, measures, part, end, *, scales, sequences, rhythms, initial=None):
+  timeline = generator.scales.timeline.read({'measures': measures}, initial=initial)
+  region = generator.scales.timeline.Solo(fractions.Fraction(), end, part.capitalize() + ' Solo')
+  choices = generator.scales.selection.select(timeline, region, scales)
+  for choice in choices:
+    if choice.span.chord and choice.scale is None:
+      raise ValueError(f'{part} solo, source measure {choice.span.source_measure}, beat {choice.span.beat}, {generator.harmony.symbol(choice.span.chord)}: No exact match within the permitted catalog')
+  plans = generator.solo.planning.plans(analysis, measures, choices, end, part, sequences)
+  # A protected quote may change the local collection, never its individual pitches.
+  for plan in plans:
+    if plan.treatment != 'quote' or plan.motif.duration > plan.end - plan.start:
+      continue
+    retained = tuple((plan.start + n.start, plan.start + n.end, {n.pitch.number() % 12}) for n in plan.motif.notes)
+    if all(pc <= generator.solo.types.permitted(choices, start, finish) for start, finish, pc in retained):
+      continue
+    alternative = generator.scales.selection.select(timeline, region, scales, retained=retained)
+    if all(pc <= generator.solo.types.permitted(alternative, start, finish) for start, finish, pc in retained) and all(c.scale or c.span.chord is None for c in alternative):
+      choices = tuple(dataclasses.replace(c, reason=c.reason + '; retained quotation') if any(a < c.span.end and b > c.span.start for a, b, _ in retained) else c for c in alternative)
+  phrases, previous = [], None
+  for plan in plans:
+    phrase = generator.solo.realization.compose(plan, measures, choices, sequences, rhythms, analysis.tempo, previous)
+    phrases.append(phrase)
+    notes = tuple(n for d in phrase.decisions for n in d.notes)
+    if notes:
+      previous = notes[-1]
+  result = generator.solo.types.Solo(part, choices, tuple(phrases), analysis.tempo, end)
+  validate(result)
+  return result
+
+def validate(solo):
+  previous = None
+  for note in solo.notes():
+    if note.start < 0 or note.end > solo.end or note.end <= note.start or previous and previous.end > note.start:
+      raise ValueError(f'{solo.part} solo: overlapping or out-of-bounds note at {note.start}')
+    if note.pitch.number() % 12 not in generator.solo.types.permitted(solo.choices, note.start, note.end):
+      raise ValueError(f'{solo.part} solo: held pitch {note.pitch.label()} violates a scale span at {note.start}-{note.end}')
+    if note.position not in generator.fretboard.positions_for_pitch(fractions.Fraction(note.pitch.number())):
+      raise ValueError(f'{solo.part} solo: invalid guitar placement at {note.start}')
+    previous = note
+  for phrase in solo.phrases:
+    notes = tuple(n for d in phrase.decisions for n in d.notes)
+    if not generator.solo.realization.target_ok(notes, phrase.plan.target):
+      raise ValueError(f'{phrase.plan.id}: planned harmonic arrival was not realized')