I want to know this too, I tried a pile of things as well but nothing worked. I think I saw on discord somewhere that it isn’t implemented yet? Not sure though.
Hello,
you can’t initialize a listenable interface inside a class.
For now, I recommend exposing an event like the CountdownEndedEvent (for example OnTimerIteration/OnTick) that lets users of the class Await it. You’d then Signal the event when needed.
I haven’t played around with it much, but maybe something like this could also be helpful to you:
# In this case the functions we accept should take one string parameter and return void.
my_fun := type{_(:string):void}
my_subscribable := class:
var Funs<private>:[]my_fun = array{}
Subscribe<public>(Fun:my_fun):void =
set Funs += array{Fun}
Dispatch<private>():void =
for (Fun:Funs):
Fun("Hello")
o/ Is there a way to implement custom subcribable events with generics?
Ideally You’d want my_subscribable use subscribable and signalable, be parametric type passing t:type to Funs as you do.
But seems we are hitting dead end of “sane” here with mutables not implemented in parametric types, so how would one go about using those interfaces in custom events?
By “sane” dead end I mean relatively not way-arounds approach, for example user Ep8Script#8819 posted this:
custom_cancelable<public> := class:
var Canceled : logic = false
CancelEvent : event() = event(){}
Cancel():void=
set Canceled = true
CancelEvent.Signal()
custom_subscribable<public>(t:type)<computes> := class<public>(awaitable(t)):
InnerEvent : event(t) = event(t){}
Subscribe(Callback:type {__(:t):void}):custom_cancelable=
Cancelable := custom_cancelable{}
spawn{_WaitForEvent(Callback, Cancelable)}
Cancelable
_WaitForEvent(Callback:type {__(:t):void}, Cancelable: custom_cancelable)<suspends>:void=
race:
# Wait for payload to be sent
loop:
Payload := InnerEvent.Await()
# Just in case
if(not Cancelable.Canceled?):
Callback(Payload)
else:
break # Just in case
# Cancelable got canceled
Cancelable.CancelEvent.Await()
Signal<public>(Payload:t):void =
InnerEvent.Signal(Payload)
Await<override>()<suspends>:t=
InnerEvent.Await()
These might not be stored along in an array of cancelable, but it seem to work good (forgetting that it uses spawns)
EDIT: For anyone wanting to use this, just need to warn you, the garbage collector will not clean up the suspending calls
So each .Subscribe() call will stay alive untill you manually call .Cancel() or .CancelAll()
So to say, try to not dynamically generate .Subscribe() calls and you should be fine
Here I’ve writen a custom timer divice, which we can call any where in our code, with events call in every secound and on the end of the timer that we can subscribe.
Check it here:
Sorry to resurrect an old thread, but for anyone coming here looking for this solution (which is awesome btw – thanks @im_a_lama!), the problem (“Can’t access a function from a preceding type”) is that parametric types can’t be referenced outside of the file that declared them (for now). The workaround for this is to place the file that’s using the custom listenable into it’s own submodule; this subverts the compiler error (and works!). So, you should have something like this:
I don’t recommend beginners to actually do so, creating folders will also create modules and it’s a hassle to work with, one can just rename custom_subscribable.verse to _custom_subscribable.verse forcing the parametric class to actually be compiled before any other code
My solution above was recommended by an Epic dev in another thread elsewhere. It’s actually part of one of their tutorials.
I had no idea this would actually work. Does it really satisfy the linter? Cause it won’t let you compile otherwise. If so, I really wish I knew this before I migrated ALL of my devices to a submodule! That was a major PITA.
Like any other software developer, Epic members don’t always know how to use their tools, they’re making them, I know modules are recommended they’re just a hassle to use, especially with parametrics
Yes my solution works properly (as long as your file is at the root of your project ig?)
My solution above was recommended by an Epic dev in another thread elsewhere. It’s actually part of one of their tutorials.