libtcspc.Count¶

final class libtcspc.Count(event_type, access_tag)[source]¶

Bases: Node

Processor that counts events of a given type, passing every event through.

The running count can be retrieved at any time during execution via the CountAccess retrieved from the ExecutionContext using access_tag. The counter is incremented before each matching event is forwarded, so an observer reading the count immediately after the Nth matching event sees the value N.

Parameters:

event_type (EventType) – The event type whose occurrences are counted. Other event types are forwarded but not counted.
access_tag (AccessTag) – Tag used to retrieve a CountAccess from the ExecutionContext at runtime.

Notes

Events handled:

Events matching event_type: increment counter, then pass through.
All other event types: pass through unchanged.
End of input: pass through.