https://github.com/bodil/purescript-signal

Elm style FRP library for PureScript
https://github.com/bodil/purescript-signal

Last synced: 24 days ago
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Elm style FRP library for PureScript

• Host: GitHub
• URL: https://github.com/bodil/purescript-signal
• Owner: bodil
• License: apache-2.0
• Created: 2014-09-19T20:27:49.000Z (about 10 years ago)
• Default Branch: master
• Last Pushed: 2022-04-30T07:51:12.000Z (over 2 years ago)
• Last Synced: 2024-10-01T04:24:22.590Z (about 1 month ago)
• Language: PureScript
• Size: 242 KB
• Stars: 259
• Watchers: 14
• Forks: 44
• Open Issues: 8
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-purescript - purescript-signal
• awesome-purescript - purescript-signal - An asynchronous signal library for PureScript, similar to Elm. (Asynchronicity and Parallelism)

README

        
# purescript-signal

[![Build Status](https://travis-ci.org/bodil/purescript-signal.svg?branch=master)](https://travis-ci.org/bodil/purescript-signal)

Signal is a lightweight FRP-like library heavily inspired by the Elm Signal implementation. Where possible and sensible, it tries to maintain API equivalence with Elm.

See [the Elm documentation](http://elm-lang.org:1234/guide/reactivity#signals) for details on usage and principles.

## PureScript Usage Patterns

PureScript depends on effects (specifically, the `Effect` monad) to manage side effects, where Elm's runtime generally manages them for you. `purescript-signal` provides the `Signal.runSignal` function for running effectful signals.

```purescript

module Main where

import Effect.Console

import Effect (Effect)

import Prelude

import Signal

hello :: Signal String

hello = constant "Hello Joe!"

helloEffect :: Signal (Effect Unit)

helloEffect = hello ~> log

main = runSignal helloEffect

```

This simple example takes a constant signal which contains the string `"Hello Joe!"` and maps it over the `Effect.Console.log` function, which has the type `String -> Effect Unit`, thus taking the `String` 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 (Effect Unit)`. 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.

## API Documentation

* [Module documentation on Pursuit](https://pursuit.purescript.org/packages/purescript-signal/)

## Usage Examples

* The canonical Elm Mario: https://github.com/michaelficarra/purescript-demo-mario

* Ponies: https://github.com/bodil/purescript-is-magic