Elm signal system for Haskell
|LTS Haskell 20.15:||0.1.2|
|Stackage Nightly 2023-03-24:||0.1.2|
|Latest on Hackage:||0.1.2|
Module documentation for 0.1.2
Ramus is a lightweight FRP-like library heavily inspired by the Elm Signal implementation, in fact, it’s a direct port of the purescript-signal library, in Haskell. Where possible and sensible, it tries to maintain API equivalence with Elm.
See the Elm documentation for details on usage and principles.
Haskell Usage Patterns
Haskell depends on
IO to manage side effects, where Elm’s runtime generally manages them for you.
ramus provides the
Signal.runSignal function for running effectful signals.
module Main where import Signal hello :: Signal String hello = constant "Hello Joe!" helloEffect :: Signal (IO ()) helloEffect = hello ~> print main :: IO () main = runSignal helloEffect
This simple example takes a constant signal which contains the string
and maps it over the
(Show a) => a -> IO(), thus taking the
content of the signal and turning it into an effect which logs the provided string to the user’s console.
This gives us a
Signal (IO ()). We use
runSignal to take the signal of effects and run each effect
in turn—in our case, just the one effect which prints
"Hello Joe!" to the console.