QueueType
Queue
Queue<'a> hands each value from producer fibers to exactly one taker, in FIFO order, with an overflow strategy chosen
when it is created. Several fibers can take from one queue and share its values between them. This module creates
queues and offers to them; take values, inspect, and shut a queue down with the
Dequeue functions, which accept a Queue.
Create a queue with make and a QueueStrategy, or with a shorthand:
bounded suspends producers while full, dropping discards the new
value, sliding evicts the oldest, and unbounded never refuses.
makeScoped shuts the queue down when the current scope closes.
Interrupting a suspended offer never enqueues its value, and interrupting a suspended take never
loses one. When zero or many consumers must each see every value, use a Hub instead.
tryOffer returns immediately and can be called from a synchronous callback. Its
QueueTryOfferResult distinguishes acceptance, a full back-pressure queue, discard, eviction, and shutdown. A Full
or Shutdown result leaves the offered value outside the queue.
Read the Queue guide for strategies, batching, shutdown, and draining on stop.
Specification
Summary
| Name | Signature | Synopsis |
|---|---|---|
| Operations | ||
| droppingNow | Queue.droppingNow capacity | Creates a dropping queue synchronously for synchronous producers such as UI event handlers. |
| shutdownNow | Queue.shutdownNow queue | Shuts down a queue synchronously, waking any suspended consumers. |
| make | Queue.make strategy | Creates a queue with the given overflow strategy. |
| makeScoped | Queue.makeScoped strategy | Creates a queue that is shut down when the current scope closes. |
| bounded | Queue.bounded capacity | Creates a lossless queue whose offer suspends while it holds capacity values. |
| dropping | Queue.dropping capacity | Creates a queue whose offer discards the new value and returns false when full. |
| sliding | Queue.sliding capacity | Creates a queue whose offer evicts the oldest value when full and returns true. |
| unbounded | Queue.unbounded () | Creates a queue that never rejects or suspends an offer. |
| offer | Queue.offer value queue | Adds a value according to the queue's strategy. |
| tryOffer | Queue.tryOffer value queue | Tries to add a value immediately, without starting a Flow or suspending the caller. |
| offerAll | Queue.offerAll values queue | Adds values in order according to the queue's strategy. |
Operations
Parameters
| Name | Type | Description |
|---|---|---|
| strategy | QueueStrategy |
Returns
Verification Examples
flow {
let! (jobs: Queue<string>) = Queue.makeScoped (QueueStrategy.BackPressure 64)
do! jobs |> Queue.offer "first job" |> Flow.ignore
}
|> Flow.scopedParameters
| Name | Type | Description |
|---|---|---|
| values | 'a seq | |
| queue | Queue<'a> |
Returns
Verification Examples
flow {
let! (samples: Queue<float>) = Queue.unbounded ()
do! samples |> Queue.offerAll [ 1.0; 2.0; 3.0 ] |> Flow.ignore
return! samples |> Dequeue.takeUpTo 500
}