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Distributed Event Bus Subpackage (bus)

The bus module provides a thread-safe in-process publish/subscribe message broker supporting hierarchical wildcard topic routing, subscription identifiers, and bounded history tracking.

API Reference

bus.sub(pattern: String, handler: Function): Int

Subscribes a callback function to a topic pattern. Returns a subscription handle identifier integer. - Exact match: "orders.created" - Single-level wildcard: "orders.*" - Multi-level wildcard: "*" or "**"

def main(): Int {
  const sub_id = bus.sub("telemetry.*", |topic: String, payload: String| {
    print("Received on {topic}: {payload}")
  })
  return 0
}

bus.pub(topic: String, payload: String): Int

Publishes an event to topic. Handlers are dispatched in a lock-free execution context to prevent deadlocks. Returns the count of matching subscribers notified.

def main(): Int {
  bus.pub("telemetry.cpu", "88.4")
  bus.pub("telemetry.memory", "4096")
  return 0
}

bus.unsub(id: Int): Bool

Unregisters a subscription handle by ID. Returns true if found and removed.

bus.history(topic: String, limit: Int): [String]

Retrieves up to limit previously published messages matching topic.

bus.clear(): Void

Resets all subscribers and clears the event history log.