Module `Async_bus`

Async operations on Core_kernel.Bus.

val pipe1_exn : ('a -> unit, [> Core_kernel.read ]) Core_kernel.Bus.t -> Core_kernel.Source_code_position.t -> 'a Async_kernel.Pipe.Reader.t: pipe1_exn t returns a pipe of updates from t by subscribing to t. Closing the pipe unsubscribes from t. Closing t closes the pipe. pipe1_exn raises in the same circumstances as subscribe_exn.

module First_arity : sig ... end

val first_exn : ?⁠stop:unit Async_kernel.Deferred.t -> ('c, [> Core_kernel.read ]) Core_kernel.Bus.t -> Core_kernel.Source_code_position.t -> ('c, 'f, 'r) First_arity.t -> f:'f -> 'r Async_kernel.Deferred.t

first_exn here t arity ~f returns a deferred that becomes determined with value r when the first event is published to t where f returns Some r. first_exn then unsubscribes from t, ensuring that f is never called again after it returns Some. first_exn raises if it can't subscribe to the bus, i.e., if subscribe_exn raises. If f raises, then first_exn raises to the monitor in effect when first_exn was called. first_exn takes time proportional to the number of bus subscribers.

If stop is provided and becomes determined, f will not be called again, it will unsubscribe from the bus, and the deferred that was returned by first_exn will never become determined.