khodowany
109 lines
5.4 KiB
Python
109 lines
5.4 KiB
Python
"""Written chord, source-key motion, and bounded expressive treatments.
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There is no preselected scale map. Optional colors never rewrite a chord;
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permission follows the actual sounded interval and validated resolution.
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"""
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from __future__ import annotations
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import dataclasses
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import functools
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from fractions import Fraction as F
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from generator import harmony as chords, model
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from generator.solo import types
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@dataclasses.dataclass(frozen=True)
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class Roles:
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basic:frozenset
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specified:frozenset
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degrees:tuple
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@functools.lru_cache(maxsize=512)
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def degree_roles(kind,root,degrees):
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basic,specified,labels=set(),set(),{}
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for degree,alter in degrees:
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pc=int(root+chords.degree_semitones(degree,alter))%12
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structural=degree in (1,3,5,6,7) or degree in (2,4) and kind in ('suspended-second','suspended-fourth')
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(basic if structural else specified).add(pc);labels.setdefault(pc,[]).append(degree)
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return Roles(frozenset(basic),frozenset(specified-basic),tuple((p,tuple(v)) for p,v in sorted(labels.items())))
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def roles(chord):
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if not chord or chord['kind']=='none':return Roles(frozenset(),frozenset(),())
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root=chord['root'];pc=model.NATURAL[root['letter']]+model.alteration(root['alter'])
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return degree_roles(chord['kind'],pc,tuple(sorted(chords.degrees(chord).items())))
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@dataclasses.dataclass(frozen=True)
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class Span:
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start:F
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end:F
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roles:Roles
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chord:str
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key:dict
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pitches:frozenset
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@dataclasses.dataclass(frozen=True)
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class Result:
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valid:bool
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exposure:float
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pending:tuple=()
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error:str=''
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class Harmony:
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def __init__(self,spans,profile=None):
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from generator.solo.profiles import UNRESTRICTED
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self.profile=profile or UNRESTRICTED
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self.source_spans=spans;self.spans=[];self.color_eligibility={}
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for s in spans:
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r=roles(s.chord)
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key=frozenset((model.NATURAL[l]+int(model.fraction(a)))%12 for l,a in zip(model.LETTERS,s.key['alterations']))
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self.spans.append(Span(s.start,s.end,r,chords.symbol(s.chord) if s.chord else 'N.C.',s.key,key|r.basic|r.specified))
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self.spans=tuple(self.spans)
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@functools.lru_cache(maxsize=2048)
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def at(self,time):return next((s for s in self.spans if s.start<=time<s.end),None)
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def segments(self,n):return tuple((s,max(n.start,s.start),min(n.end,s.end)) for s in self.spans if s.start<n.end and s.end>n.start)
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@functools.lru_cache(maxsize=8192)
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def members(self,start,end):
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spans=[s for s in self.spans if s.start<end and s.end>start]
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return frozenset.intersection(*(s.roles.basic|s.roles.specified for s in spans)) if spans else frozenset()
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@functools.lru_cache(maxsize=8192)
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def permitted(self,start,end):
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spans=[s for s in self.spans if s.start<end and s.end>start]
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return frozenset.intersection(*(s.pitches if s.chord!='N.C.' else frozenset() for s in spans)) if spans else frozenset()
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def function(self,number,span):
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pc=number%12
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return 'basic' if pc in span.roles.basic else 'specified_extension' if pc in span.roles.specified else 'diatonic_motion' if pc in span.pitches else 'chromatic'
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def step(self,a,b,time):return 0<abs(a-b)<=2
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def connected_motion(self,notes,index):
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if not 0<index<len(notes)-1:return ''
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a,n,b=notes[index-1:index+2]
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if a.end!=n.start or n.end!=b.start:return ''
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left=n.pitch.number()-a.pitch.number();right=b.pitch.number()-n.pitch.number()
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return 'neighbor' if 0<abs(left)<=2 and left==-right else 'passing' if 0<abs(left)<=2 and 0<abs(right)<=2 and left*right>0 else ''
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def evaluate(self,notes,*,until=None,complete=False,expressions=()):
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from generator.solo.expressions import validate_frontier
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notes=types.sounding_notes(notes)
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frontier=until if until is not None else max((n.end for n in notes),default=F())
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permissions,pending,error=validate_frontier(notes,expressions,self,frontier,complete or until is None)
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if error:return Result(False,0,error=error)
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exposed=sounded=F()
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for n in notes:
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covered=n.start;duration=n.end-n.start;sounded+=duration
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for s,a,b in self.segments(n):
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if a!=covered or s.chord=='N.C.':return Result(False,0,error=f'{n.event_id}: missing written/carried harmony')
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covered=b;permission=permissions.get(n.event_id)
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if permission and permission.kind=='anticipation' and a>=permission.boundary:permission=None
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pc=n.pitch.number()%12
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if pc in s.roles.basic|s.roles.specified or permission:continue
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if pc not in s.pitches:return Result(False,0,error=f'{n.event_id}: unsupported chromatic event')
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if duration>=2 and n.role!='quote':return Result(False,0,error=f'{n.event_id}: sustained nonchord tone needs an explicit treatment')
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exposed+=(b-a)/4
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if covered!=n.end:return Result(False,0,error=f'{n.event_id}: incomplete harmonic coverage')
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return Result(True,float(exposed/max(F(1,1000),sounded)),pending)
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def describe(self,notes,expressions=()):
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from generator.solo.expressions import validate
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permissions,error=validate(notes,expressions,self)
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if error:raise ValueError(error)
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return [{'start':str(a),'end':str(b),'attack':str(n.start),'sounding_duration':str(n.end-n.start),
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'pitch':n.pitch.label(),'chord':s.chord,'function':self.function(n.pitch.number(),s),
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'expression':permissions[n.event_id].kind if n.event_id in permissions else '',
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'expression_rule':permissions[n.event_id].rule if n.event_id in permissions else '',
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'protected':n.role=='quote'} for n in notes for s,a,b in self.segments(n)]
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