* Subscriptions on pubsubs

[leshy]

Allowing pubsubs to pattern match (or subscribe all) would allow us to create generic bridges

"all protocols to rerun"

"ros to lcm"

"lcm to foxglove" <- 2 line fg bridge

etc

current spec

class PubSub(Generic[TopicT, MsgT], ABC):
    """Abstract base class for pub/sub implementations with sugar methods."""

    @abstractmethod
    def publish(self, topic: TopicT, message: MsgT) -> None:
        """Publish a message to a topic."""
        ...

    @abstractmethod
    def subscribe(
        self, topic: TopicT, callback: Callable[[MsgT, TopicT], None]
    ) -> Callable[[], None]:
        """Subscribe to a topic with a callback. returns unsubscribe function"""
        ...

what would be an api for this?

pubsub.subscribe_all()

or do we just agree about regex or * matching?

issue is obviously general protocol pattern matching capability, not everything can regex, how do we specify this?

proposal:

SubAllPubsub(Pubsub):
     @abstractmethod
     def subscribe_all():
         ....

# implies .subscribe() supports "/bla/*" for topics, but not full regex
StarPubsub(SubAllPubsub):
    ...

# supports full regex
RegexPubsub(SubAllPubsub):
    ...

so we can specify type layer topic pattern matching capability,
provide subscribe_all method for this common usecase