Events¶

The library has basic support for events and patterns. However it differs from the original implementation to keep basic functionality as simple and fast as possible. Because of that, the only user level supported event type is NoteEvent which has all the keys sets of the original ‘note’ event. The event types necessary for Pmono are implemented internally (with support for PmonoArtic integrated through the articulate argument). Nevertheless, it’s easy to create new event types in a possible future.

Events are Python dictionaries with extended functionality that mimics SuperCollider’s Environment class, although they are not environments here and don’t have exactly the same behavior.

Events are created through the sc3.seq.event.event which in fact is a subclass dict with the particularity that event instances are callable to implement default key values.

e = event()  # Create a NoteEvent type by defaults
print(e)  # An empty NoteEvent({}) dictionary
e['freq']  # KeyError
e('freq')  # As callable returns the default freq value
e.play()  # Play the event.

Event keys are organized in sets as in SuperCollider, each key set may define the value of related keys if they are chained and so on. The way to obtain the value of a given default key is to invoke the key with parenthesis instead of brackets. The main use for events is to perform notes by sending a bundle with all the required data and setting the release command if applicable.

The sc3 builtin function play knows how to play events if invoked with keyword only arguments or by passing in a dict object.

play()  # Plays the default NoteEvent.
play(midinote=69, dur=3)  # Keyword only arguments
play({'midinote': 69, 'dur': 3})  # Dictionary
play({'midinote': 69}, dur=3)  # Mixed (same interface as dict)

Using play as the interface makes it easy to use plain Python dictionaries as data structures for storing data while also performing default keys lookup through event. This way, concrete event instances are disposable, they are only used to interpret the keys and build the messages.