Introduction to Elixir

Slides for the "Introduction to Elixir" talk I gave at the first Elixir/Erlang meetup in Italy, set in Bologna (October 2015).

Transcript

1. introduction to Elixir
2. Erlang compiles to bytecode
3. Elixir is what would happen if Erlang, Clojure and Ruby somehow had a baby and it wasn't an accident Devin Torres
4. Andrea Leopardi @whatyouhide
5. metaprogramming tooling interop concurrency features
6. features
7. data structures
8. 199 "t-rex" :dr_manhattan [:red, :white, :blue] {:error, "nope"} %{hair: :red, weight: :high}
9. immutability
10. all data structures are immutable
11. animals = ["lion", "table", "bear"] List.delete(animals, "table") animals #=> ["lion", "table", "bear"]
12. data+functions
13. data functions modules
14. String.upcase("meh") m o d u l e f u n c t i o n d a t a
15. defmodule String do def upcase(str) do # ... end end
16. high-order functions
17. doubler = fn(i) -> i * 2 end Enum.map([1, 2, 3], doubler) #=> [2, 4, 6]
18. pattern matching
19. = ≠ =
20. match the structure of the data bind variables while doing that
21. [first, second, third] = [ :houston, :austin, :dallas, ] first #=> :houston second #=> :austin
22. [first, second, _] = [ :houston, :austin, :dallas, ] first #=> :houston second #=> :austin
23. [first, second, _] = [ :houston, :austin, :dallas, :seattle, ] ** (MatchError)
24. protocols
25. à la Clojure
26. JSON.encode(thing) defines API
27. defprotocol JSON do def encode(thing) end
28. JSON.encode(thing) dispatches to implementation
29. defimpl JSON, for: Integer do def encode(i), do: # ... end
30. concurrency
31. Any sufficiently complicated concurrent program in another language contains an ad hoc informally-specified bug-ridden slow implementation of half of Erlang. Robert Virding
32. spawn fn -> IO.puts "from another process" end
33. not OSprocesses
34. lightweight isolation message passing
35. for _ <- 1..100_000 do spawn(fn -> :ok end) end lightweight
36. animals = [:dog, :cat] spawn fn -> animals # it's a copy end isolation
37. isolation per-process garbage collection!!!
38. message passing the only way processes can communicate
39. pid = spawn fn -> # ... end send pid, "a message" message passing
40. spawn fn -> receive do msg -> :ok end end message passing
41. spawn_monitor fn -> raise "die!" end receive do m -> m end #=> {:DOWN, ...} message passing
42. actor model
43. def loop(state) do receive do {from, :get} -> send(from, state) loop(state) {from, :put, new_state} -> loop(new_state) end end
44. def loop(state) do receive do {from, :get} -> send(from, state) loop(state) {from, :put, new_state} -> loop(new_state) end end
45. def loop(state) do receive do {from, :get} -> send(from, state) loop(state) {from, :put, new_state} -> loop(new_state) end end
46. def loop(state) do receive do {from, :get} -> send(from, state) loop(state) {from, :put, new_state} -> loop(new_state) end end
47. def loop(state) do receive do {from, :get} -> send(from, state) loop(state) {from, :put, new_state} -> loop(new_state) end end
48. def loop(state) do receive do {from, :get} -> send(from, state) loop(state) {from, :put, new_state} -> loop(new_state) end end
49. def loop(state) do receive do {from, :get} -> send(from, state) loop(state) {from, :put, new_state} -> loop(new_state) end end
50. def loop(state) do receive do {from, :get} -> send(from, state) loop(state) {from, :put, new_state} -> loop(new_state) end end
51. def loop(state) do receive do {from, :get} -> send(from, state) loop(state) {from, :put, new_state} -> loop(new_state) end end spawn(&loop/0)
52. Node.spawn(node, fun)
53. interop
54. Elixir data structures are Erlang data structures
55. lists:map(fun(X) -> X * 2 end, [1, 2, 3]). :lists.map(fn(x) -> x * 2 end, [1, 2, 3])
56. :queue.in("customer1", :queue.new())
57. tooling
58. iex> 8 * 2 16 IEx
59. mix new my_app compile test deps.get Mix
60. test "math works!" do assert 1 + 1 end ExUnit
61. Hey there, <%= name %>! EEx
62. defp deps do [{:phoenix, "~> 1.0"}, {:ecto, "~> 1.0"}] end Hex
63. so
64. lots of companies use Elixir in prod it's awesome to work with thriving ecosystem, smart devs phoenix metaprogramming
65. @whatyouhide