FRP code is write-only about sodium HOT 7 CLOSED

There are three things I would say:

• First, you are used to imperative code but not to FRP code. This gives imperative code an unfair advantage.
• Second, the syntax of FRP is terrible. I talk about this briefly in the book. It could be improved hugely with some kind of preprocessor. It'd be great to standardize that.
• FRP is semantically simpler and easier to make modular. The advantages increase as the code size gets bigger.

from sodium.

Agree, so I need the rules how to write and read FRP code.

This syntax can not be simplier in java. Mb in kotlin. The one thing I really dont like is loops. kotlin can make this part less verbose, but not totally eliminates the problem:

    val sink = Sodium.streamSink<Int>()
    val cell = Sodium.tx {
        val cell = cellLoop<Int>()
        cell loop sink.filter {
            it.value > cell.sample().value
        }.hold(0)
        cell
    }

from sodium.

That's why the best solution is a preprocessor. In Haskell loops are just forward/cyclic references, enabled with the keyword 'rec':

(sink, sendSink) <- newEvent
rec
    cell <- hold 0 $ filterJust
                   $ snapshot (\c s -> if c > s then Just s else Nothing) sink cell

A preprocessor would also allow for auto-lifting and type inference, e.g.

Cell<Integer> a = Cell.lift((b_, c_) -> b_ + c_, b, c)

becomes

a <- b + c

from sodium.

There is FRP language: http://elm-lang.org/

from sodium.

ELM has the same syntax as Haskell, so it has type inference, which is great. But it doesn't have auto-lifting and there are probably other things we can improve.

from sodium.

scala.react, as described in http://infoscience.epfl.ch/record/176887/files/DeprecatingObservers2012.pdf provides some much more readable syntax, at least for behaviours. the way it's done is not exactly pretty, but with some macros - like the ones https://github.com/pelotom/effectful provides - the same could be achieved in a much better way.

from sodium.

Of course I would love to improve FRP syntax, but given that Sodium has a lot of work to do yet to get things working on multiple languages, I am going to consider this area not within the immediate scope of Sodium for now and close this bug.

from sodium.