Module Picos_std_structured.Promise

A cancelable promise.

ℹ️ In addition to using a promise to concurrently compute and return a value, a cancelable promise can also represent a concurrent fiber that will continue until it is explicitly canceled.

type !'a t

Represents a promise to return value of type 'a.

val of_value : 'a -> 'a t

of_value value returns a constant completed promise that returns the given value.

ℹ️ Promises can also be created in the scope of a Bundle or a Flock.

val await : 'a t -> 'a

await promise awaits until the promise has completed and either returns the value that the evaluation of the promise returned, raises the exception that the evaluation of the promise raised, or raises the Terminate exception in case the promise has been canceled.

val completed : 'a t -> 'a Picos_std_event.Event.t

completed promise returns an event that can be committed to once the promise has completed.

val is_running : 'a t -> bool

is_running promise determines whether the completion of the promise is still pending.

val try_terminate : ?callstack:int -> 'a t -> bool

try_terminate promise tries to terminate the promise by canceling it with the Terminate exception and returns true in case of success and false in case the promise had already completed, i.e. either returned, raised, or canceled.

The optional callstack argument specifies the number of callstack entries to capture with the Terminate exception. The default is 0.

val terminate : ?callstack:int -> 'a t -> unit

terminate promise is equivalent to try_terminate promise |> ignore.

val terminate_after : ?callstack:int -> 'a t -> seconds:float -> unit

terminate_after ~seconds promise arranges to terminate the promise by canceling it with the Terminate exception after the specified timeout in seconds.

The optional callstack argument specifies the number of callstack entries to capture with the Terminate exception. The default is 0.