Async

Utils

SetTimeout

Spawns an asynchronous task (a wrapper over SchelduleTask), that evaluates an expression once

SetTimeout[expr_, interval_Real | interval_Quantity] _TaskObject

A symbol has HoldFirst attribute. An interval is in milliseconds. To cancel it, use

CancelTimeout[_TaskObject]

SetInterval

Spawns an asynchronous task (a wrapper over SchelduleTask), that evaluates an expression every interval milliseconds

SetInterval[expr_, interval_Real | interval_Quantity] _TaskObject

A symbol has HoldFirst attribute. To cancel this task use

TaskRemove[_TaskObject]

or

CancelInterval[_TaskObject]

PauseAsync

It works similar to Pause, but returns Promise

Then[PauseAsync[3], Beep];

TableAsync

It works similar to Table, but the inner expression can be implicit AsyncFunction

n = EvaluationCell[];

Then[TableAsync[
  PauseAsync[1] // Await;
  i
, {i,3}], CellPrint[#, "After"->n]&];

DoAsync

Works in the same way as TableAsync

More

Note, that there are more expressions in the standard library, which support patterns of async programming:

• FrontFetchAsync
• ChoiceDialogAsync
• SystemDialogInputAsync
• ParallelSubmitAsync
• ParallelSubmitFunctionAsync
• ExportAsync
• RasterizeAsync
• DoAsync
• TableAsync
• PauseAsync
• MMAViewAsync
• AsyncFunction
• Any EventObject: InputButton and etc

Asynchronous Functions

AsyncFunction

It works similar to Function

AsyncFunction[args, body] _Promise

One can use it as normal function, but utilizing Await keyword. On the background it restructures body in the runtime.

Await

Holds the execution (non blocking to threads) until the promise is resolved and returns the result

Await[_ | _Promise] _

If the argument is not Promise it won't pause the execution and return the result without changes.

• Set
• CompoundExpression
• If
• Module, With
• _Symbol or any other singular expressions
• TableAsync
• DoAsync
• PauseAsync
• any expression, that returns Promise or EventObject

What is not supported (by now)

• Loops: While, For, Do
• Tables and maps: Map, Table
• Return will not work correctly inside AsyncFunction

For example:

btn = InputButton[]

Then[AsyncFunction[x, Module[{res},
  Speak["Click to start"];
  btn // Await;
  Speak["Choose"];
  res = ChoiceDialogAsync["Add 10?"] // Await;
  If[res, x + 10, x] 
]][10], Speak];