# runtime/eval-async Queue source on a child runtime's loop thread; returns a request id immediately. ## Syntax

[runtime/eval-async $name $source ?$reply-topic]

## Parameters - `$name` — child runtime name - `$source` — deft source string to evaluate - `$reply-topic` — optional pub/sub topic for the result (default `"runtime/eval-result"`) ## Examples

[runtime/eval-async "worker" "(+ 1 2)" "my/eval-done"]

## Returns Request-id string. Result delivered via pub/sub as `%{ :id :value :output :error }`. ## See Also `runtime/eval`, `runtime/spawn`, `pub/subscribe`