Chord Families

generator/chord_families.py

@@ -1,5 +1,6 @@
 """Transposable guitar families, derived from the written chord and legal grips."""
 import generator.harmony
+import generator.fretboard
 import generator.model
 import generator.vocabulary
 
@@ -47,3 +48,7 @@ def coverage(chord, options, part):
       result.append({'bass_string': string, 'bass_degree': degree, 'candidates': len(found), 'preferred': sum(f['preferred'] for f in found),
         'reason': '' if found else 'no legal grip for this bass under written harmony and current fret/span limits'})
   return result
+
+def span_coverage(options):
+  return {'primary': sum(not generator.fretboard.span_penalty(v) for v in options),
+    'fallback': sum(generator.fretboard.span_penalty(v) for v in options)}