Why Elixir? (Intro to Elixir)

A brief introduction of Elixir. Level: beginners.

Transcript

1. WHY ELIXIR? Elixir Sofia Meetup May 2017
2. WHY ELIXIR? INTRO TO ELIXIR
3. Ventsislav Nikolov @ventsislaf
4. DISCLAIMER NO GIFs
6. WHAT IS ELIXIR?
7. • functional programming language • compiles to erlang bytecode • immutable data • dynamically typed • concurrency, distribution, fault tolerance • hot code swapping
8. DATA TYPES (NOT ALL) 1_000_000 # Integer 314159.0e-5 # Float :apple # Atom "Jon Snow" # String {:error, 404} # Tuple [1, 2, 3] # (Linked) List %{name: "Jon", age: 21} # Map
9. MODULES AND FUNCTIONS
10. ANONYMOUS FUNCTIONS add = fn(a, b) -> a + b end add.(2, 5) # => 7
11. MODULES defmodule Math do def add(a, b) do a + b end defp multiply(a, b) do a * b end end # warning: function multiply/2 is unused Math.add(2, 5) # => 7 Math.multiply(2, 5) # ** (UndefinedFunctionError) function Math.multiply/2 is undefined or private
12. IMMUTABILITY
13. colors = ["green", "apple", "red"] List.delete(colors, "apple") # => ["green", "red"] colors # => ["green", "apple", "red"]
14. PATTERN MATCHING
15. = x = 1 # => 1 1 = x # => 1 2 = x # ** (MatchError) no match of right hand side value: 1 x = 2 # => 2
16. DECOMPOSITION [x, y] = [1, 2] # x => 1, y => 2 [1, x] = [1, 2] # x => 2 [_, x] = [1, 2] # x => 2 [head | tail] = [1, 2, 3] # head => 1, tail => [2, 3] %{name: name} = %{name: "Jon Snow", age: 21} # name => "Jon Snow"
17. RECURSION
18. def sum([]) do 0 end def sum([head | tail]) do head + sum(tail) end
19. PIPE OPERATOR
20. Enum.sort(String.codepoints(String.downcase(word)))
21. lowercase = String.downcase(word) chars = String.codepoints(lowercase) ordered = Enum.sort(chars)
22. word |> String.downcase() |> String.codepoints() |> Enum.sort()
23. Elixir + Erlang = ❤
24. # Erlang rand:uniform(10). # Elixir :rand.uniform(10)
25. CONCURRENCY
26. PROCESSES (not OS) spawn fn -> IO.puts "Hello from another process" end
27. LIGHTWEIGHT • created for couple of microseconds • 1-2 KB initial memory footprint • up to hundreds of millions processes per VM
28. ISOLATION name = "Jon Snow" spawn fn -> IO.puts "Hello, #{name}" end
29. MESSAGES pid = spawn fn -> receive do msg -> IO.puts "received a message: #{msg}" end end send pid, "You know nothing, Jon Snow."
30. msg 1 msg 2 msg 3 mailbox
31. FAULT TOLERANCE
32. :one_for_one :one_for_all
33. DISTRIBUTION
35. $ iex --name one@host $ iex --name two@host $ iex --name three@host # in node one iex> Node.connect :two@host iex> Node.connect :three@host iex> Node.list # => [:two@host, :three@host] # in node two iex> Node.list # => [:one@host, :three@host] iex> Node.spawn :three@host, fn -> IO.puts("hello") end
36. TOOLING
37. IEx (demo) $ iex iex> 2 + 5 7
38. MIX mix new app_name mix compile mix test mix deps.get mix hex.publish
39. OBSERVER :observer.start
41. WHERE TO GO NEXT?
46. THANK YOU!