Intro to Erlang*

*and the BEAM

Who am I?

Erik Nilsen
enilsen16 on most places
I tweet about random things

Work at answerky
In Brisbane and QUT as part of the Hotdesq program.

What I hope you get from this talk

Well thought out language
Being used in interesting ways
Distributed Computing is cool
I want to leave you curious :D

What you won't get from this talk

Deep dive into OTP
Live coding examples
Almost every slide in this presentation could be it's own talk.

For more information on any of these topics come talk to me.

The Actor Model

Individual actors can only modify their own state
To communicate with other actors they pass messages
This concept was co-created by Carl Hewitt

So what is Erlang?

Erlang is a general-purpose programming language and runtime environment. Erlang has built-in support for concurrency, distribution and fault tolerance. Erlang is used in several large telecommunication systems from Ericsson.

http://erlang.org/faq/introduction.html

Cool...

What Does that MEAN?

Erlang is a functional programming language with a large emphasis on Concurrency and High Reliability.
Pattern Matching and Immutable data are core features
Erlang allows for dozens of tasks or processes to preform at the same time. (Actor Model)
Each process runs separately inside BEAM, the virtual machine.
Message passing between processes is the only way to interact.

Why was it created?

When you are building systems, you're going to have failures that are out of your control. (Hardware, Network Layer Failures, Etc..)
Their also may be bugs, that only happen in certain situations. (These can be extremely hard to reproduce.)
When programming telecom systems or 911 call centers you can't afford for the entire system to go down.

Who created it?

Ericsson wrote the first version in 1986
Originally written in Prolog(Hence the syntax)

OTP Overview

BEAM	Use case
Standard Library	Erlang
Common Test, Eunit	Testing Frameworks
Mnesia	A Database
ETS	A key/value store(in memory)
Dialyzer	A type checker

http://erlang.org/doc/applications.html

There's a lot more...

Erlangs ability to work with other languages

C and C++
Java
Ruby
Rust
Python

Who Uses Erlang?

League Of Legends chat system(Riot Games)
WhatsApp, Whisper, FB Messenger
Almost all telecom companies
Adroll(for real time bidding)
Ericsson(Currently developing 5G)
Basho Riak, RabbitMQ
A lot more

A short look at the Erlang Syntax

-module(count_to_ten).

-export([count_to_ten/0]).

 

count_to_ten() -> do_count(0).


do_count(10) -> 10;
do_count(N) -> do_count(N + 1).

Other Languages That Run on BEAM

Elixir (Ruby Like)
Lisp flavored Erlang(lfe)
Alpaca(ML like syntax)

Elixir

Written by Jose Valim
Ruby-like syntax
Popular Libraries around it
Includes improved tooling
Modern community

Show me the Numbers

ErLang SYTAX Example

Elixir Sytax Example

-module(count_to_ten).

-export([count_to_ten/0]).


count_to_ten() -> do_count(0).


do_count(10) -> 10;
do_count(N) -> do_count(N + 1).

defmodule CountToTen do
  def count_to_ten do
    do_count(0)
  end

  defp do_count(10), do: 10
  defp do_count(x) do
    do_count(x+1)
  end
end

Popular Erlang and Elixir Projects

Nerves
Phoenix
QuickCheck
Riak

How does Erlang Apply to Distributed Computing

Well First why is distributed Computing hard?

I mean this is a mostly solved problem right

*slide from http://bit.ly/2qVavtl

What is the problem?