Functional Reactive Programming in Scala

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Solution 1

See also Odersky et al.'s paper "Deprecating the Observer Pattern". It explains the library Scala.React, which was developed for the paper.

Solution 2

There's reactive -- http://github.com/nafg/reactive. The repository currently contains two projects. reactive-core is a standalone FRP library. reactive-web builds on it to make it very easy to make very dynamic and interactive Lift webapps.

Solution 3

There is scala-reactive: http://github.com/erikrozendaal/scala-reactive

It is inspired by Microsoft's Reactive Extensions library, with an Observable trait taking the place of IObservable, and tailored to the Scala collections API as much Rx is to the LINQ API.

22,718

Author by

Daniel C. Sobral

I have been programming for more than 20 years now, starting with 8 bits computers, assembler and BASIC. My passion for languages meant that, by the time I entered college, I had already programmed for fun or profit in more than 20 languages, including odd ones like Forth, MUMPS and APL, as well as theoretically important ones like Lisp and Prolog. Some of my code ended up in FreeBSD, of which I was a committer for some years, while I got my masters degree in the field of distributed algorithms. I also contributed to Scala, with small amounts of code, some reasonable amount of documentation, and a couple of years of a lot of attention to the Scala questions on Stack Overflow.

Updated on April 29, 2020

Comments

Daniel C. Sobral almost 4 years

Are there any libraries written for Scala enabling Functional Reactive Programming?
Roland Tepp over 13 years

This paper is actually very good. It really made me understand what is all the fuzz in FRP all about...
Mariusz Pawelski over 11 years

here is new version.
Jeff Axelrod over 11 years

Also see stackoverflow.com/q/11619680/403455
Shelby Moore III over 11 years

@DanielC.Sobral I provided an example for inverting the control of state using Scala's delimited continuations, not just inversion-of-control of caller/callee, which afaics that paper and Scala.React don't do.
Owen about 11 years

I tried reactive-core in a Swing GUI and found it quite pleasant to use. The biggest pain is actually language related -- Scala could use nicer syntax for applicatives.
nafg about 11 years

@Owen - that's interesting. Where do you use applicatives? P.S. Do you have a Swing bridge that's shareable?
Owen about 11 years

Signal is an applicative. And I didn't use any sort of bridge; I just mixed reactive code in with Swing code -- a little messy since the swing components are so stateful, but usable. The whole thing will be on github eventually.
nafg about 11 years

How is Signal an applicative?
Owen about 11 years

pure is a constant signal, and ap is doing a zip followed by a map. So if say I have a signal x and a signal y and I want a signal x + y, x zip y map { case (x, y) => x+y } is like scalaz (x |@| y)(_ + _).
nafg about 11 years

Ah thanks for the info. If you like, feel free to open an issue to add applicative syntax.
Vadzim over 10 years

What's the status of Scala.React? github.com/ingoem/scala-react
nafg almost 10 years

@Owen just added it. github.com/nafg/reactive/commit/…