Re: [elm-discuss] Re: Why is the signature of 'program.subs' 'model -> Sub msg' ?
My understanding is that yes, Elm does this with every update and then the effects managers have to look at the new subscriptions and compare them to the old subscriptions. I would love to hear that my understanding is wrong because while this isn't bad if you have just a few subscriptions, it seems like potentially a lot of overhead if you have a lot of subscriptions. One could envision subscriptions being implemented more like views in which there would be a differ that would generate patches to send to the effects managers and there would be a subscription equivalent to Html.Lazy that would cut off a lot of the computation when nothing had changed. This would probably make frequent update to subscriptions less scary computationally but it isn't how things are done. Finally, you haven't asked the other subtle question brought on by dynamic subscriptions: if you stop returning a subscription, are you guaranteed that you won't receive any messages targeted to that subscription or are you only guaranteeing that no more messages will be queued or even weaker are you only letting the effects manager know that you aren't really interested any more? Mark On Fri, Jul 21, 2017 at 6:55 AM Vasily Vasilkov wrote: > Does it mean that Elm runtime creates and cancels subscriptions on the fly > (for every model change)? > > > > On Mon, Jul 17, 2017 at 6:19 PM +0400, "Marek Fajkus" > wrote: > > Sometimes you don't need subscriptions if you're in some state. For >> instance, if you have game and subscription to say mouse position you can >> subscribe to Mouse.position only when a user is in play state and avoid >> subscription in game menu. >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Elm Discuss" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to elm-discuss+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > -- > You received this message because you are subscribed to the Google Groups > "Elm Discuss" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to elm-discuss+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [elm-discuss] Re: Why is the signature of 'program.subs' 'model -> Sub msg' ?
Does it mean that Elm runtime creates and cancels subscriptions on the fly (for every model change)? On Mon, Jul 17, 2017 at 6:19 PM +0400, "Marek Fajkus" wrote: Sometimes you don't need subscriptions if you're in some state. For instance, if you have game and subscription to say mouse position you can subscribe to Mouse.position only when a user is in play state and avoid subscription in game menu. -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[elm-discuss] Re: Why is the signature of 'program.subs' 'model -> Sub msg' ?
On Monday, July 17, 2017 at 9:19:00 AM UTC-5, Marek Fajkus wrote: > > Sometimes you don't need subscriptions if you're in some state. For > instance, if you have game and subscription to say mouse position you can > subscribe to Mouse.position only when a user is in play state and avoid > subscription in game menu. > Because the game menu would only need to detect clicks and not positions? and/or would be made out of HTML with buttons that have an attached 'onClick' event. (Thus freeing you from needing to subscribe to even 'Mouse.clicks', right?) On ... art yerkes wrote: > > Updates take CPU time, heat up your user's laptop, reinvigorate cold > memory, often when your user is trying to use their computer for other > things. If running some code won't be useful, you should avoid running > it. It also saves the environment just a tiny amount. > Ah, okay, so there is a performance advantage. On ... Aaron VonderHaar wrote: > > Another example is a package like WebSocket, where the package will open a > network connection while you are subscribed and close it when you stop > subscribing. > Interesting. -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [elm-discuss] Re: Why is the signature of 'program.subs' 'model -> Sub msg' ?
Another example is a package like WebSocket, where the package will open a network connection while you are subscribed and close it when you stop subscribing. On Jul 17, 2017 7:19 AM, "Marek Fajkus" wrote: Sometimes you don't need subscriptions if you're in some state. For instance, if you have game and subscription to say mouse position you can subscribe to Mouse.position only when a user is in play state and avoid subscription in game menu. -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[elm-discuss] Re: Why is the signature of 'program.subs' 'model -> Sub msg' ?
Sometimes you don't need subscriptions if you're in some state. For instance, if you have game and subscription to say mouse position you can subscribe to Mouse.position only when a user is in play state and avoid subscription in game menu. -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[elm-discuss] Re: Why is the signature of 'program.subs' 'model -> Sub msg' ?
Updates take CPU time, heat up your user's laptop, reinvigorate cold memory, often when your user is trying to use their computer for other things. If running some code won't be useful, you should avoid running it. It also saves the environment just a tiny amount. On Monday, July 17, 2017 at 6:03:03 AM UTC-7, John Bugner wrote: > > The signature of program.subs (from > http://package.elm-lang.org/packages/elm-lang/core/5.1.1/Platform ) is: > 'model -> Sub msg'. > > Why isn't it just 'Sub msg' ? What's the point of including the model in > there? Sure, it lets you control what subscriptions you listen too > depending on the current model, but what's the benefit of that? Is it wise > to rely on this function to control what messages you receive? The update > function still has to have a case for every message no matter the state, > after all. Is there some performance improvement from using this that I'm > not aware of? > > -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
