anandgeorge

Access help functions for a module using the h command; so 

h String

will give you help related to the String function 

#### Data types

iex> 2         # integer
iex> 2.0       # floating point

anandgeorge

defmodule Game do
  use GenServer

  def init(game_id) do
    {:ok, %{game_id: game_id}}
  end

  def start_link(game_id) do
    GenServer.start_link(__MODULE__, game_id, name: {:global, "game:#{game_id}"})
  end

anandgeorge

Elixir Supervision Trees Made Easy

I started with Elixir just a couple weeks after the switch from 1.4 to 1.5, so the bulk of online resources were out of date (or at least resulted in deprecation warnings). This guide is for defining Elixir 1.5 supervised modules.

It's not actually terribly complicated. It's just sometimes unclear from examples what's implemented by the language and what you actually have to implement yourself.

Say we want a supervision tree like this (where each atom is a process):

    :a

/ \

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population = for _ <- 1..100, do: for _ <- 1..1000, do: Enum.random(0..1)

# evaluate, selection, crossover and algorithm are anonymous functions.

evaluate = 
	fn population -> 
			# population is a list of lists [[1,1,0,0,1...1,1,0],[1,1,1,0,0...0,1,1]] 100 lists, 1000 bits each
		Enum.sort_by(population, &Enum.sum/1, &>=/2) 
			# sort the list of lists by sum of bits so lists with higher number of one's are at the top. Mapper sums each row. Sorter is descending &>=/2
			# note the use of anonymous functions defined by &.

anandgeorge

My Elixir Study Notes

Important Links

• Writing Assertive Code With Elixir

Notes

• Get some help:

iex> i 'hello'
Term

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// The code is based on a MongoDB database myhome with a typical record as below:
// {
//	"rec_time" : ISODate("2013-11-25T16:53:43.808Z"),
//	"rec_data" : {
//		"power" : 372.201,
//		"current" : 1.73,
//		"voltage" : 221.678,
//	},
//	"rec_asset" : {
//		"name" : "Airconditioner",

anandgeorge

var io = require('socket.io').listen(8000),
	nicknames = {};

io.sockets.on('connection', function (socket) {
  socket.on('user message', function (msg) {
    socket.broadcast.emit('user message', socket.nickname, msg);
  });

  socket.on('nickname', function (nick, fn) {
    if (nicknames[nick]) {

anandgeorge

Some exercises from the Falsy Values workshops.

The good parts:

• HTTP server and client in same script
• Express cookies example
• Express routing example
• Express error handling
• Express middlewares example
• Simple HTTP proxy

anandgeorge

/**
 * Read Linux mouse(s) in node.js
 * Author: Marc Loehe (marcloehe@gmail.com)
 *
 * Adapted from Tim Caswell's nice solution to read a linux joystick
 * http://nodebits.org/linux-joystick
 * https://github.com/nodebits/linux-joystick
 */

var fs = require('fs'),

anandgeorge

#!/usr/bin/env node

CHANNEL = '#bozler'
MINIMUM_HUMAN_REACTION = 2

DIALOGUE = 
  ACTIONS_IN_REPLY: [
    "I vote for pizza",
    "Disregard that, I vote for pizza",
    "Another vote for pizza!"