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# tink
  • f
    I'm working with tink.core and running into some issues with 
    PromiseTrigger
    and 
    FutureTrigger
    I have a UI object with callbacks for confirmation and cancellation. The code that sets it up looks like this:
    Copy code
    class PromptServer {
  public static function prompt() {
    final confirmOrCancel = // instantiate UI object
    final pt = Promise.trigger();

    confirmOrCancel.confirmationHandler = () -> {
      trace("confirmed");
      pt.trigger(Success("bar"));
    };

    confirmOrCancel.cancelHandler = () -> {
      trace("cancelled");
      pt.trigger(Failure(new Error(null, "foo")));
    };

    return pt.asPromise();
  }
}
    Another class calls 
    prompt()
    to try to pass along the 
    Promise
    , like so:
    Copy code
    function showPrompt() {
    return PromptServer.prompt().next(val -> {
      trace(val);
      return val;
    });
  }
    The returntype of 
    showPrompt()
    is 
    Promise<String>
    , but when I trigger the confirmation handler, I only see the "confirmed" trace. When I step into 
    pt.trigger
    , the 
    CallbackList
    is empty. I've tried this with both 
    Promise.trigger()
    and 
    Future.trigger()
    to the same effect. Am I misusing something here, or misunderstanding something about how 
    Future
    and 
    Promise
    are supposed to function?
  • l
    that might be what's happening with @await then too, I only get Success, never Failure
  • l
    here's a simpler example, hangs on the @await the second time...
    Copy code
    package;

using tink.CoreApi;

@await class Futures
{
    static function main()
    {
        var inst = new Futures();
    }

    function new()
    {
        init();
    }

    @async function init()
    {
        var s = @await successOrFailure(true);
        trace('Should return a true from Succed(true): $s');
        var f = @await successOrFailure(false);
        trace('Should return an Error from Failure: $f');
    } 

    function successOrFailure(succeed:Bool)
    {
        return Future.async(yield -> succeed ? yield(Success(true)) : yield(Failure(new Error(101,'I am failure.'))));
    }
}
  • l
    looks to be the same prob with the Promise/Future?
  • c
    .next() is only run for a success promise
  • c
    You need to .handle() the error
  • c
    In case of tink await, you need to try catch the error
  • l
    ok, so in the example above, where I'm creating the error, yield is never called? Is that the .next()? How do I return the Failure with the Error in?
  • c
    Your yield part is ok
  • c
    You just need to try/catch the call site
  • c
    Simplest way here is to wrap the whole function body of init() in a try catch block
  • l
    so there's no way of returning the Failure?
  • l
    Copy code
    @async function init()
    {
        try
        {
            var s = @await successOrFailure(true);
            trace('Should return a true from Succed(true): $s');
            var f = @await successOrFailure(false);
            trace('Should return an Error from Failure: $f');
        }
        catch(e)
        {
            trace(e);
        }
    } 

    function successOrFailure(succeed:Bool):Surprise<Bool, Error>
    {
        return Future.async(yield -> succeed ? yield(Success(true)) : yield(Failure(throw new Error(101,'I am failure.'))));
    }
  • l
    thanks, that traces the success call, then doesn't trace the lines after the second call which is caught int he catch block
  • l
    I think I can work with that 😄
  • l
    works without the throw in the Failure too
  • l
    cool thanks kevin
  • f
    I see, I misunderstood it to be literally "do this next and return the result as a new `Promise`/`Future`". I hadn't wired up a 
    handle
    on the other end because I was trying to get the callback to tell me it was doing anything before I even tried! A bit surprising that it doesn't trigger 
    next
    callbacks if there's nothing to 
    handle
    the final result, even if those have side effects. But I can understand the rationale.
  • c
    Hey! Any plan to update the library to use the new isOfType? I am getting this warning
    Copy code
    Warning : Std.is is deprecated. Use Std.isOfType instead.
  • e
    make a pr
  • c
    Do you think it will be reviewed? I opened an issue on January and don't get any response
  • e
    ¯\_(ツ)_/¯
  • a
    an issue vs a pr, and a particularly simple pr may have different results
  • c
    👍🏻
  • c
    I think you opened an issue in tink lang? That one is sort of obsolete unfortunately, because many functions are already built into the language itself.
  • c
    And yeah PR will be more welcome then issues in general
  • c
    > because many functions are already built into the language itself. That is something I thought... that a lot of things felt like were already solved by Haxe itself, but I had not enough experience with Haxe to decide for myself
  • l
    It'd be nice if Tink Lang got a new major version that removes any deprecated syntax
  • s
  • s
    #579634919576436736erbell