Delayed messages

[matmleave]

• A general case is that one may want to send a message later, like do something after 10 secs, or do something when mouse clicks next time, instead of doing something right now
• planned effect:

type LayerMsg
    = ...
    | LayerMsgDelayedOnce (EnvC -> Maybe LayerMsg)       -- triggered only once
    | LayerMsgDelayed (EnvC -> Maybe LayerMsg)           -- always valid

• example1: If one want to send 1 to a layer called "A" when mouse is clicked next time

updateModel env lmsg model =
    ...
    let cond fenv =
        case fenv.msg of
            MouseDown _ _ ->
                Just (LayerIntMsg 1)
            _ ->
                Nothing
    in
    (model, [(LayerName "A", LayerMsgDelayedOnce cond)], env)

• example2: If one want to send 1 to layer "A" after some time, then write

updateModel env lmsg model =
    ...
    let cond fenv =
        case fenv.msg of
            Tick t ->
                let cond2 fenv2 =
                    case fenv2.msg of
                        Tick t2 ->
                            if (toSecond utc t2) >= (toSecond utc t) + 100 then
                                Just (LayerIntMsg 1)
                            else
                                Nothing
                        _ ->
                            Nothing
                in 
                Just (LayerMsgDelayedOnce cond2)
            _ ->
                Nothing
   (model, [(LayerName "A", LayerMsgDelayedOnce cond)], env)

this will start counting time after next Tick.

[linsyking]

This could be implemented by event bus subsystem which might be implemented as a component.

[Monolitho]

Yes... But since it is a highly-demanded feature in game-development, I still would say it is necessary to add it into messenger.

[linsyking]

Using the latest messenger, this could be implemented easily as a global component. We could implement this in extra.

Yes... But since it is a highly-demanded feature in game-development, I still would say it is necessary to add it into messenger.