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generator/solo/groups.py

@@ -7,59 +7,66 @@ not a rhythmic boundary and must not be used to clip a group.
 from __future__ import annotations
 import dataclasses
 import functools
-from fractions import Fraction as F
-
+import fractions
 
 @dataclasses.dataclass(frozen=True)
 class RhythmGroup:
-  start: F
-  end: F
+  start: fractions.Fraction
+  end: fractions.Fraction
   family: str
-  events: tuple[tuple[F, F], ...]
-  displacement: F = F()
+  events: tuple[tuple[fractions.Fraction, fractions.Fraction], ...]
+  displacement: fractions.Fraction = fractions.Fraction()
   source: str = ''
 
-
-def describe(pattern, *, origin=F(), source='', imported=False):
-  if not pattern:return ()
+def describe(pattern, *, origin=fractions.Fraction(), source='', imported=False):
+  if not pattern:
+    return ()
   if imported:
-    return (RhythmGroup(origin, origin+pattern[-1][1], 'source', pattern, source=source),)
-  result=[]; i=0
-  while i<len(pattern):
-    a,b=pattern[i]
-    if b<=a or i and a<pattern[i-1][1]:raise ValueError('overlapping rhythm group')
+    return (RhythmGroup(origin, origin + pattern[-1][1], 'source', pattern, source=source),)
+  result = []
+  i = 0
+  while i < len(pattern):
+    a, b = pattern[i]
+    if b <= a or i and a < pattern[i - 1][1]:
+      raise ValueError('overlapping rhythm group')
     # A complete ternary figure can be intentionally displaced on an eighth.
-    if (b-a).denominator%3==0:
-      if (a*2).denominator!=1:raise ValueError('unexplained tuplet entry phase')
-      start=i; cursor=a
-      while i<len(pattern):
-        x,y=pattern[i]
-        if x!=cursor or (y-x).denominator not in (3,6):break
-        cursor=y;i+=1
-        if (cursor-a).denominator==1:break
-      if i==start or (cursor-a).denominator!=1:
+    if (b - a).denominator % 3 == 0:
+      if (a * 2).denominator != 1:
+        raise ValueError('unexplained tuplet entry phase')
+      start = i
+      cursor = a
+      while i < len(pattern):
+        x, y = pattern[i]
+        if x != cursor or (y - x).denominator not in (3, 6):
+          break
+        cursor = y
+        i += 1
+        if (cursor - a).denominator == 1:
+          break
+      if i == start or (cursor - a).denominator != 1:
         raise ValueError('incomplete tuplet group')
-      group=pattern[start:i]
-      result.append(RhythmGroup(origin+a,origin+cursor,'triplet',group,a%1,source))
+      group = pattern[start:i]
+      result.append(RhythmGroup(origin + a, origin + cursor, 'triplet', group, a % 1, source))
     else:
-      if (a*4).denominator!=1 or (b*4).denominator!=1:
+      if (a * 4).denominator != 1 or (b * 4).denominator != 1:
         raise ValueError('unexplained binary subdivision phase')
-      family='sixteenth' if (a*2).denominator!=1 or (b*2).denominator!=1 else 'binary'
-      result.append(RhythmGroup(origin+a,origin+b,family,((a,b),),a%1,source));i+=1
+      family = 'sixteenth' if (a * 2).denominator != 1 or (b * 2).denominator != 1 else 'binary'
+      result.append(RhythmGroup(origin + a, origin + b, family, ((a, b),), a % 1, source))
+      i += 1
   return tuple(result)
 
-
 @functools.lru_cache(maxsize=8192)
 def valid(pattern):
-  try:describe(pattern);return True
-  except ValueError:return False
-
+  try:
+    describe(pattern)
+    return True
+  except ValueError:
+    return False
 
 def signature(notes):
   """Translation-invariant duration, inter-onset and rest vocabulary."""
-  return tuple((n.end-n.start, notes[i+1].start-n.end if i+1<len(notes) else F())
-    for i,n in enumerate(notes))
-
+  return tuple((n.end - n.start, notes[i + 1].start - n.end if i + 1 < len(notes) else fractions.Fraction())
+    for i, n in enumerate(notes))
 
 def descriptor(pattern, duration):
   """Retain ordered attacks, durations and space, including a trailing breath.
@@ -69,11 +76,12 @@ def descriptor(pattern, duration):
   """
   return (duration, tuple(pattern))
 
-
 def broaden(pattern, arrival, release):
   """Reopen an editable binary tail; never slice a tuplet or inherit its phase."""
-  if (arrival*2).denominator!=1 or (release*2).denominator!=1:return ()
+  if (arrival * 2).denominator != 1 or (release * 2).denominator != 1:
+    return ()
   for group in describe(pattern):
-    if group.family=='triplet' and group.start<arrival<group.end:return ()
-  result=tuple((a,min(b,arrival)) for a,b in pattern if a<arrival)+((arrival,release),)
+    if group.family == 'triplet' and group.start < arrival < group.end:
+      return ()
+  result = tuple((a, min(b, arrival)) for a, b in pattern if a < arrival) + ((arrival, release),)
   return result if valid(result) else ()