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https://issues.apache.org/jira/browse/GROOVY-9381?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18030751#comment-18030751
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Guillaume Laforge commented on GROOVY-9381:
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Cool!
I don't have particular feedback on the implementation, but I'm definitely
looking forward to this feature!
I'm also curious to know how this will work with other libraries, frameworks,
indeed like GPars, but also things like RxJava or Reactor, if it will simplify
using those tools too.
> Support async/await like ES7
> ----------------------------
>
> Key: GROOVY-9381
> URL: https://issues.apache.org/jira/browse/GROOVY-9381
> Project: Groovy
> Issue Type: New Feature
> Reporter: Daniel Sun
> Priority: Major
>
> Here is the proposed syntax and backend API(Java's {{CompletableFuture}} or
> GPars's {{Promise}}), but I think it's better for Groovy to have its own
> {{Promise}} to decouple with Java API because async/await as a language
> feature should be as stable as possible.
> {code:java}
> /**
> * 1. An async function that simulates a network API call.
> * The 'async' keyword implies it runs asynchronously without blocking.
> */
> async fetchUserData(userId) {
> println "Starting to fetch data for user ${userId}..."
>
> // Simulate a 1-second network delay.
> Thread.sleep(1000)
>
> println "Fetch successful!"
> // The 'async' function implicitly returns a "CompletableFuture" or
> "Promise" containing this value.
> return [userId: userId, name: 'Daniel']
> }
> /**
> * 2. An async function that uses 'await' to consume the result.
> */
> async processUserData() {
> println "Process started, preparing to fetch user data..."
>
> try {
> // 'await' pauses this function until fetchUserData completes
> // and returns the final result directly.
> def user = await fetchUserData(1)
>
> println "Data received: ${user}"
> return "Processing complete for ${user.name}."
>
> } catch (Exception e) {
> return "An error occurred: ${e.message}"
> }
> }
> // --- Execution ---
> println "Script starting..."
> // Kick off the entire asynchronous process.
> def future = processUserData()
> // This line executes immediately, proving the process is non-blocking.
> println "Script continues to run while user data is being fetched in the
> background..."
> def result = future.get()
> println "Script finished: ${result}"
> {code}
> Use async/await with closure or lambda expression:
> {code}
> // use closure
> def future = async {
> println "Process started, preparing to fetch user data..."
>
> try {
> // 'await' pauses this function until fetchUserData completes
> // and returns the final result directly.
> def user = await fetchUserData(1)
>
> println "Data received: ${user}"
> return "Processing complete for ${user.name}."
>
> } catch (Exception e) {
> return "An error occurred: ${e.message}"
> }
> }
> {code}
> {code}
> // use lambda expression
> def future = async () -> {
> println "Process started, preparing to fetch user data..."
>
> try {
> // 'await' pauses this function until fetchUserData completes
> // and returns the final result directly.
> def user = await fetchUserData(1)
>
> println "Data received: ${user}"
> return "Processing complete for ${user.name}."
>
> } catch (Exception e) {
> return "An error occurred: ${e.message}"
> }
> }
> {code}
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