forkAction doesn't work as expected?

[potocpav]

I need to make AJAX calls in the background which wouldn't be interrupted by GUI events. I tried to use forkAction for this purpose, but it doesn't work as expected. The background request completes, but the resulting event isn't propagated to the calling Widget if any other event occurs in the meantime.

Here is a test-case demonstrating the issue:

module Test.Main where

import Prelude

import Concur.Core (Widget)
import Concur.Core.Patterns (forkAction)
import Concur.React (HTML)
import Concur.React.DOM as D
import Concur.React.Props as P
import Concur.React.Run (runWidgetInDom)
import Control.MultiAlternative (orr)
import Effect (Effect)
import Effect.Aff (Milliseconds(..), delay)
import Effect.Aff.Class (liftAff)
import Effect.Class (liftEffect)
import Effect.Class.Console (log)

main :: Effect Unit
main = runWidgetInDom "root" (forkAction computation mainWidget)

computation :: Widget HTML Unit
computation = liftAff (delay $ Milliseconds 2000.0) *> liftEffect (log "sent")

mainWidget :: forall void. Widget HTML Unit -> Widget HTML void
mainWidget comp = do
  ev <- orr
    [ "Click" <$ D.button [P.onClick] [D.text("Click")]
    , "Delay" <$ comp
    ]
  liftEffect $ log $ "received " <> show ev
  mainWidget comp

If I click the button before computation finishes, then Delay is never printed.

I think this used to work fine a year ago, though I am not positive. I wasn't able to build old Concurs to test it.

[srghma]

yes, the functionality of forkAction is unclear because of the lack of documentation

i.e. the orr function have a race like behavior (when one of the widgets finishes -> other are killed)

but should it kill the forked/remote widget? what is remote widget? unclear

probably the tests should be added for forkAction and remoteWidget

[potocpav]

Where should I add the orr? What do you mean by "race like behavior"?

[srghma]

@potocpav I have updated my comment