Elixir

ElixirRobert Brown

@robby_brown@robert_brown@rob-brown

What is Elixir?

A Ruby-inspired language built on the Erlang Virtual Machine

Extends Erlang with macros, pipelines, and sigils

Your next programming language

What is Erlang?

Created in 1986 by Ericsson

Open sourced in 1998

Functional, concurrent language

Based on Prolog, Smalltalk, CSP, and functional programming

Advantages of Erlang

Fault tolerant

Lightweight processes

Hot code swapping

“Let it crash” philosophy

Advantages of Erlang

Battle-tested libraries

Soft real time

Trivial parallel processing

Trivial network protocol processing

Advantages of Erlang

Pattern matching

Tail recursion

Garbage Collected

Advantages of Erlang

http://www.slideshare.net/JanHenryNystrom/productivity-gains-in-erlang

Who Uses Erlang?

Amazon

Yahoo!

Facebook

T-Mobile

Motorola

Ericsson

WhatsApp

Huffington Post

CouchDB

GitHub

Basho

RabbitMQ

Call of Duty

League of Legends

Goldman Sachs

http://en.wikipedia.org/wiki/Erlang_(programming_language)

Why Learn Functional Programming?

The future is in parallel processing

Easier to debug

Many languages are adopting FP techniques

Actor Model

Actors can be created/destroyed and send/receive messages

All state is encapsulated

In Elixir, each actor is its own process

Elixir Syntax: Numbers

!

42

123.456

1_000_000

!

0b101010 (binary)

0xdeadc0de (hex)

034 (octal)

Elixir Syntax: Tuples

{ 1, 2, 3 }

{ 3.14, :hello, “world” }

Elixir Syntax: List

[ ]

[ 1, 2, 3 ]

[ head | tail ]

[ first, second | tail ]

Elixir Syntax: Atom

:atom

:“with spaces”

Elixir Syntax: Binary

“Elixir”

<<“Elixir”>>

<< 69, 108, 105, 120, 105, 114 >>

Elixir Syntax: Character List

‘Elixir’

[ ?E, ?l, ?i, ?x, ?i, ?r ]

[ 69, 108, 105, 120, 105, 114 ]

Elixir Syntax: Range

1..100

10..0

-10..10

Elixir Syntax: Pipeline

IO.puts(“Hello world!”)

“Hello world!” |> IO.puts()

!

IO.puts(String.upcase(“Elixir”))

“Elixir” |> String.upcase() |> IO.puts()

Elixir Syntax: Regex

~r“^[A-Z]$”

“101010” =~ ~r“^[01]+$”

Elixir Syntax: Operators+ - * / ! = == === != !== > >= < <=

and or xor not

&& ||

[ 1, 2, 3 ] ++ [ 4, 5, 6 ]

[ 1, 2, 3 ] -- [ 2 ]

“Hello ” <> “World!”

Elixir Syntax: Fn

fn (x) -> x * x end

&(&1 * &1)

!

fn (x, y) -> x + y * 2 end

&(&1 + &2 * 2)

Elixir Syntax: Modules and Functionsdefmodule Demo do

def say_hello() do

IO.puts(“Hello”)

end

def say_goodbye(), do: IO.puts(“Goodbye”)

defp private_function(), do: “Top Secret”

end

Pattern Matching

“=” operator does not mean “assign”

It’s the matching operator

Think of “=” in terms of math

Pattern Matching

x = 42

[ a, b, c ] = [ 1, 2, 3 ]

[ d, d, e ] = [ 4, 4, 5 ]

{ ^x, y } = { 42, 99 }

Pattern Matching

{ :ok, data } = File.read(“Demo.txt”)

{ :error, reason } = File.read(“Bogus.txt”)

{ a, b, _ } = Demo.do_something()

Pattern Matching

def sum(list), do: _sum(list, 0)

defp _sum([], total), do: total

defp _sum([ head | tail ], total) do

_sum(tail, head + total)

end

Pattern Matching

fn (x) when rem(x, 15) == 0 -> “FizzBuzz”

(x) when rem(x, 3) == 0 -> “Fizz”

(x) when rem(x, 5) == 0 -> “Buzz”

(x) -> x

end

Pattern Matching

<< number::[ bitstring, size(16) ],

“ ”,

word::[ bitstring, size(48) ] >> =

“42 Elixir”

PID

Process ID

Returned from spawn and spawn_link

Transfer messages with send and receive

PID: spawn

pid = spawn(fn -> do_something() end)

pid = spawn(Demo, :do_something, [])

pid = spawn(&Demo.do_something/0)

pid = spawn_link(fn -> 1 / 0 end)

PID: send

send(pid, 42)

send(pid, { self, :something })

send(pid, { self, fn (x) -> x * x end })

PID: receivereceive do

{ from, :something } ->

send(from, { self, do_something() }

{ :EXIT, from, reason } -> IO.puts(“#{from} died by #{reason}”)

after 60 * 1000 ->

:timeout

end

Questions?

Demo

Want to Learn More?

Elixir Lang

Elixir Cheat Sheet

Programming Elixir

Programming Erlang

Want to Learn More?

!

Productivity Gains In Erlang

Joe Armstrong

Evan Miller

Russel Dillin