Le 23/05/2017 à 16:23, 'Rupert Smith' via Elm Discuss a écrit : > On Tuesday, May 23, 2017 at 3:04:01 PM UTC+1, Christophe de Vienne wrote: > > A discussion around a concept of "middleware", able to define its own > Cmd and Sub that it could rewrite along with updating its own state > (which can be a part of the app model), would be interesting. > > Cmd and Sub are pretty opaque beasts from where I stand, may be we can > already do such a thing. > > > There are modules that build their own subscriptions, for example: > > http://package.elm-lang.org/packages/mdgriffith/elm-style-animation/3.5.5/Animation > > provides a function to build a subscription. This is just a convenience > function; under the covers the animations are being iterated as a timer > ticks, so the real Sub being created is a timer one. > > So I think if you can define what flexible 'command' and 'subscription' > constructor functions you think the middleware needs, and we can try and > map those down to the simplest Cmd and Sub implementations that cover > all the needed use cases, then that gives us what we would need to > implement in an effects module. Essentially, it would be a messaging > kernel that is flexible enough that any reasonable messaging application > you like can be built on top of it.
It is what I did at first, but it has serious drawbacks. The biggest was that a subscription implies an update of the Nats state... so I had to push the state to all the update functions and they had to sent it back... Very messy. The final API I have, although it has some boilerplate, is a lot nicer. -- Christophe de Vienne -- 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.
