chrisbuttery

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

---

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

---

chrisbuttery

{-|
> ```
Consider a simple model for whether a person has the flu or not. Let F=1
indicate that a person has the flu and F=0 indicate that they don't have the
flu. Let C=1 indicate that the person has a cough and C=0 indicate that they
don't have a cough. Let M=1 indicate that the person has muscle pain and M=0
indicate that they don't have muscle pain. Assume that C and M are conditionally
independent given F so that the probability model is
    P(C=c,M=m,F=f)=P(C=c|F=f)P(M=m|F=f)P(F=f).
Suppose that we ask two different doctors to supply probabilities for this model

chrisbuttery

-- paste into http://elm-lang.org/try and click "compile"
-- http://imgur.com/gallery/W6TwgZw

import Graphics.Collage exposing (..)
import Graphics.Element exposing (..)
import Text
import Color exposing (..)
import Time
import Signal

chrisbuttery

Learning FP the hard way: Experiences on the Elm language

by Ossi Hanhinen, @ohanhi

with the support of Futurice 💚.

Licensed under CC BY 4.0.

Foreword

chrisbuttery

Using Mailboxes in Elm

Max Goldstein | July 30, 2015 | Elm 0.15.1

In Elm, signals always have a data source associated with them. Window.dimensions is exactly what you think it is, and you can't send your own events on it. You can derive your own signals from these primitives using map, filter, and merge, but the timing of events is beyond your control.

This becomes a problem when you try to add UI elements. We want to be able to add checkboxes and dropdown menus, and to receive the current state of these elements as a signal. So how do we do that?

The Bad Old Days

chrisbuttery

language: node_js

node_js:
- iojs

env:
  global:
  # https://docs.saucelabs.com/ci-integrations/travis-ci/
  # SAUCE_USERNAME
  - secure: Daa...

chrisbuttery

import test from 'tape';

const before = test;
const after = test;

// beforeEach/afterEach rely on shared state.
// That's a big anti-pattern for testing.

// It's also silly to run something before and after
// ever test -- many of your tests won't need it.

chrisbuttery

So I was curious how mocha implements their: "be synchronous if callback is undefined, be async if callback is defined". The way to do this is by using Function.length

// fn, fn -> null
function detect (fn, cb) {
  if (fn.length) return fn(() => cb())
  fn() && cb()
}

chrisbuttery

{
    "env": {
        "browser": true,
        "node": true,
        "es6": true
    },

    "ecmaFeatures": {
        "modules": [2]
    },

chrisbuttery

@mixin ie6 { * html & { @content } }

#logo {
  background-image: url("/images/logo.png");
  @include ie6 { background-image: url("/images/logo.gif"); }
}