Essa apresentação consiste em uma introdução à linguagem de programação Elixir desde a sintaxe ao ecossistema. Elixir é funcional, tem suporte a concorrência e paralelismo e tolerância a falhas, entre outras features.

1. Introdução à Elixir
Contexto, ecossistema e aplicações

2. Sobre a linguagem
● Criada em 2012 pelo José Valim ->
● Funcional
● Concorrente
● Compilada
● Interoperabilidade com Erlang
● Metaprogramação
● Polimorfismo

4. Quem está usando
● Discord
● Brex
● ThoughtWorks
● Globo.com
● Slack
● B2W Digital
● Adobe
● Pinterest
● etc

5. Elixir é bom para
● Web API/Apps
● Soft real-time (Chat Bot, Google Docs, IoT…)
● High scalability and fault tolerance
● Concurrency
● Developer happiness

6. Elixir não é bom para
● Number crunching *
● Any CPU bound *
● ...

7. O paradigma funcional λ
● Funções puras
● Imutabilidade (Variáveis, estrutura de dados)
● Composição
● Recursão
● Transparência referencial
● First class and high order functions
● Type system
● Modularidade

8. Erlang / OTP
● Usada em 50% dos switches de telecom
● Erlang Virtual Machine (Beam)
● Escalabilidade
● Alta disponibilidade
● Modelo de atores

9. Erlang / OTP
● 1986: Linguagem proprietária (Ericsson)
● 1995: OTP ("Open Telecom Platform")
● 1998: Erlang / OTP Open Sourced
● ...
● 2008: Facebook Chat
● 2010: Whatsapp
● Outros: RabbitMQ, CouchDB, Riak, Amazon SimpleDB

10. THE ERLANG
VM: BEAM
Preemptive scheduling

11. The Beam and Parallel Processing

12. Concurrent / Parallel
Context
Switch

13. Actor model
https://www.youtube.com/watch?v=ELw
Edb_pD0k
https://www.brianstorti.com/the-actor-
model/
http://dist-prog-book.com/chapter/3/
message-passing.html
Useful links:

14. Actor model
Actors are defined as independent units of computation with isolated state.
These units have two core characteristics:
● They can send messages asynchronously* to one another
● They have a mailbox which contains messages that they have received,
allowing messages to be received at any time and then queued for
processing.

15. What Can Actors Do
● Create new actors
● Receive messages and in response:
○ make local decisions (alter local state)
○ perform arbitrary, side-effecting action
○ send messages
○ respond to sender 0 or more times
● “Do not communicate by sharing memory; instead share memory by
communicating” - Effective Go

16. Actor model
● Actors process messages one at a time
● State is shared only through messages
● Actors do not share memory
● It doesn’t matter if the actor that I’m sending a message to is running
locally or in another node
● Actors knows other actors by identify
● Great project: https://akka.io/ (Java / Scala / JVM 😎)

17. Why use actors?
● Protect state
● No need for locks and synchronization
● Concurrency
● etc

18. Process-based actors (Erlang)
1. Everything is a process
2. Processes are strongly isolated
3. Process creation and destruction is a lightweight operation
4. Message passing is the only way for processes to interact
5. Processes have unique names
6. If you know the name of a process you can send it a message
7. Processes share no resources
8. Error handling is non-local
9. Processes do what they are supposed to do or fail
http://erlang.org/download/armstrong_thesis_2003.pdf

19. Supervision Tree

20. Policies

21. Umbrella project

22. Scale to distributed system

23. E A ELIXIR?

24. Basic Types

25. Tuples, Lists, Maps

26. Control Structures

27. Control Structures

28. Control Structures

29. Control Structures

30. Functions

31. Functions

32. Functions

33. Guards

34. Anonymous Functions

35. Structs

36. Protocols
Some
similarities
to an OOP
Interface

37. Pattern Matching

38. Pattern Matching (destructuring)

39. Pattern Matching Structs

40. Even More Pattern Matching

41. Pipe Operator |>

42. Simple Interop with Erlang
Can easily leverage 20+ years of Erlang libraries

43. Lodash.js?
https://hexdocs.pm/elixir/Enum.html

44. Loop?

45. Other stuff
● Modules
● Mix (tasks)
● ExUnit (tests)
● Macros
● Error Handling
● OTP Concurrency
● OTP Supervisors
● etc

46. Ecosystem
HEX
Ecto Absinthe https://github.com/h4cc/awesome-elixir
GUARDIAN

47. Handling a HTTP request

48. Handling a HTTP request

49. Handling a HTTP request

50. The Elixir way

51. The Elixir way

52. Muito
obrigado!