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HeinrichApfelmus / threepenny-gui

GUI framework that uses the web browser as a display.
https://heinrichapfelmus.github.io/threepenny-gui/
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Dynamic switching events #180

Open pepeiborra opened 7 years ago

pepeiborra commented 7 years ago

The switchE :: Event(Event a) -> m (Event a) operation provided by reactive-banana is missing in threepenny. A while ago this question came up in stackoverflow.com and you mentioned plans to implement it in threepenny, or unify threepenny and reactive-banana. Are you still planning to do this ?

I am writing a library of composable algebraic editors, and this comes up in trying to define the editor for a union type.

HeinrichApfelmus commented 7 years ago

Yes, I'm still planning to do replace the FRP implementation in Reactive.Threepenny and use Reactive.Banana instead. The reason I haven't done this yet is that Threepenny requires one or two weird primitives (e.g. for making domEvent a pure function) that are not present in Reactive.Banana yet.

pepeiborra commented 7 years ago

Would you accept contributions ? If there was a dev branch and a set of guidelines I might be able to help.

HeinrichApfelmus commented 7 years ago

Sure, I'm happy to receive contributions! 😄

I used to have a develop branch, but many people just submitted pull requests against master, so I learned to make this work. So, just submit to master if you like.

Since the project is still relatively small, I didn't make any formal guidelines. Use your best judgement; I usually review submitted code and give feedback.

That said, for this particular issue, it's probably fastest if I do the changes myself. The inner workings of reactive-banana are fairly complex and implementing the first missing primitive (Something similar to newEventsNamed in Reactive.Threepenny) relies on unsafePerformIO, which has all sort of unintended side effects (heh). The second missing primitive is about whether the UI monad can be stacked on top of MomentIO or whether a different solution is needed.

I intend to tackle these as I find free time; sorry that the state of FRP affairs in Threepenny is currently something unsatisfying.