Elixir intro

New software

for new hardware

Elixir meetup 4.0, Lviv, December 17, 2016

Elixir introduction

Hello!I am Anton Mishchuk

- Ruby developer at

Matic Insurance

- Elixir fan

- Author and maintainer of

ESpec BDD test framework

Github: antonmi

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What I’d tell you

▪ No pictures, sorry

▪ No code samples

▪ No live coding

▪ Lots of philosophy

▪ Few words about Erlang and Elixir

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The plan

▪ Software crisis?

▪ Resurrection of FP

▪ Erlang

▪ Erlang concurrency model

▪ Elixir

▪ Elixir is not Ruby

▪ You should try Elixir

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1Software crisis?

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Common characteristic of

present software

▪ low quality

▪ very inefficient

▪ difficult to maintain

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Nathan Myhrvold’s laws

▪ “Software is a gas”

▪ “Software grows until it becomes

limited by Moore’s Law”

▪ “Software growth makes Moore’s

Law possible”

▪ “Software is only limited by

human ambition and expectation”

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Nathan Myhrvold, formerly CTO at Microsoft

Niklaus Wirth’s Law:

“Software gets slower

faster than hardware

gets faster”

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Niklaus Wirth, computer scientist,

designer of several PL (incl. Pascal)

What next?

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▪ Better hardware?

or

▪ Better software?

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We are experiencing a period

of “dramatic changes”

▪ New hardware!

▪ New software!

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New hardware:

▪ Multicore systems

▪ ASIC (Application-specific

integrated circuit)

▪ FPGA (Field-programmable gate

array)

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“The von Neumann Syndrome”

New software:

Multicore crisis:

To take advantage of the additional

cores most applications have to be

rewritten

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2Resurrection of FP

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Functional programming

FP is a programming paradigm

that treats computation as the

evaluation of mathematical

functions.

FP: Data structures manipulated

through functions

OOP: Objects manipulated through

methods

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FP concepts

▪ High-order functions

▪ Pure functions

▪ Recursions

▪ Lazy evaluations

▪ Currying

▪ Closures

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History

FP:

▪ Lisp, 1950s

▪ APL, 1960s

▪ Haskell, late 80s

▪ Erlang, 1986

OOP:

▪ Simula, 1960s

▪ Smalltalk, 1970s

▪ Java, Ruby, 1995

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CPU:

▪ Single-processor machines

▪ 50%/year clock speed growth

▪ From ~10MHz to ~1GHz

RAM:

▪ Relatively expensive and slow

▪ $100/1Mb in 1990. $1/1Mb in 2000

▪ CPU cache

OOP dominating in 90s

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▪ Is OOP the only right way to to

create software?

▪ Is OOP the RIGHT way?

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Why OO sucks?

(c) Joe Armstrong

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▪ Functions do things

▪ Data structures just are

Since functions and data structures

are completely different types of

animal it is fundamentally

incorrect to lock them up in the

same cage.

Objection 1:

Data structure and functions

should not be bound together

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▪ Should “time” to be an instance

of some type?

▪ Should a simple integer number to

be an instance of some type?

Objection 2:

Everything has to be an object

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▪ lots of types with limited amount

of specific functions

Isn't it better have a smallish

number of ubiquitous data types and

a large number of small functions

that work on them?

Objection 3:

Data type definitions are

spread out all over the place

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The state is hidden and visible

only through access functions.

State is the root of all evil!

Objection 4:

Objects have private state

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Why OO was popular?

(c) Joe Armstrong

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▪ It was thought to be easy to

learn.

▪ It was thought to make code reuse

easier.

▪ It was hyped.

▪ It created a new software

industry.

Why OO was popular?

(c) Joe Armstrong

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I see no evidence of 1 and 2.

Reasons 3 and 4 seem to be

the driving force behind the

technology.

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If a language technology is so bad

that it creates a new industry to

solve problems of its own making then

it must be a good idea for the guys

who want to make money.

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3Erlang

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▪ Elixir compiler is written in

Erlang

▪ Both Elixir and Erlang compiles

into BEAM byte code

Elixir == Erlang

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▪ Ericsson, 1986

▪ Joe Armstrong, Robert Virding and

Mike Williams

▪ Open-sourced in 1998

▪ Telecom systems (telephone

switches)

▪ The latest version is 19.1

Erlang

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▪ Fault tolerance

▪ Scalability

▪ Distribution

▪ Live update

Erlang buzzwords

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▪ Ericsson

▪ WhatsApp

▪ Facebook

▪ Amazon

▪ Bet365

▪ Demonware

▪ ...

Companies using Erlang

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▪ Modules

▪ Functions

▪ Primitive data types:

atoms, integers, floats, tuples,

lists, maps, strings, binaries,

records, references, pids, ports,

funs.

Erlang components

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4Erlang concurrency model

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▪ Native threads

▪ Green threads

▪ Event loop

It is not about:

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▪ lightweight processes

▪ with isolated memory

▪ communication via messages

It is about “actors”

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In response to a message actor

receives, can concurrently:

▪ send a finite number of messages

to other actors

▪ create a finite number of new

actors

▪ Set the “state” to be used for

the next message it receives

Actors

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▪ Controlled by BEAM VM

▪ ~ 1µs to create process

▪ ~ 1kB memory per process

▪ ~ 1µs to pass a message

Erlang actors

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▪ encapsulate state

▪ communicate with other actors by

exchanging messages

More OO than objects

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▪ Tools

▪ Libraries

Design principles:

▪ Workers and Supervisors

▪ GenServer, GenFSM

▪ Event Handler and Manager

▪ Application

Erlang OTP

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5Elixir

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▪ Jose Valim, 2012

▪ Current version 1.3

▪ Hex.pm

▪ >3000 packages, ~20000 down/day

▪ Elixir Conf EU, Elixir Conf US

▪ Elixir Companies

▪ Phoenix web framework

(2M websocket conns)

Elixir

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What is Elixir?

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Elixir is Erlang with pretty syntax

and metaprogramming

▪ Consistent stdlib

▪ Pipe operator

▪ Tools (mix, iex, logger)

Elixir metaprogramming

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▪ Easy code sharing

▪ Perfect Ruby-like DSLs

6Elixir is not Ruby

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Elixir is functional

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▪ Function is a primary Elixir

abstraction.

▪ Data is immutable

▪ Minimal state manipulation

Ruby is OO language

with some FP features

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▪ Procs, lambdas

▪ No FP optimizations

▪ Data is mutable

Concurrency model

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In Ruby, one moves through a

monolithic call stack, manipulating

objects. Threads or fibers uses the

same memory heap.

Elixir processes have their own

heaps, and the VM collects process'

garbage independently of each

other.

What is the same?

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“programmer happiness” philosophy:

▪ Pretty syntax

▪ Good documentation

▪ Tools for easy development

7You should try Elixir

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Think about future software

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▪ Multi-core computers

▪ IoT with up to 30 billion devices

to be online by 2020

Double paradigm switch

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▪ Functional programming

▪ Actor concurrency model

You’ll found it exciting

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▪ It’s easy to get started

▪ Lots of tutorials

▪ Nice documentation

▪ Great community

Thanks!ANY QUESTIONS?

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