| Class Summary | 
| APhraseVisitor | Command-based implementation of IPhraseVisitor that uses IPhraseVisitorCmds stored in a hash table. | 
| Chord | A collection of notes that make up a Chord. | 
| DecoratorSeqList | An ISeqList that transparently routes the visitor execution to its decoree. | 
| FineToggleDecoratorSeqList | The class is used to implement "Da Capo al fine" or "D.C. | 
| Header | An abc Header. | 
| MTSeqList | An empty sequence list. | 
| NESeqList | A non-empty ("cons") sequence list. | 
| Note | Basic class representing musical Notes. | 
| NoteCollection | A collection of multiple notes | 
| ToggleDecoratorSeqList | Multiple Decorator ISeqList where the active decoree (the "target") is
 toggled (cycled, actually) through all the available decorees. | 
| Triplet | A musical triplet. | 
| Tuplet | Class that represents a tuplet, a series of notes played in a fraction of their normal total time. |