PromptWorks Talk Tuesdays: Ray Zane 1/17/17 "Elixir Is Cool"

An introduction to some of my favorite elixir features.

https://www.promptworks.com/

Transcript

2. |>
3. Treat.give(Dog.find(dog_id)) dog_id |> Dog.find() |> Treat.give()
4. new_email( to: "foo@example.com", from: "me@example.com", subject: "Welcome!!!", html_body: "<strong>Welcome</strong>", text_body: "welcome" )
5. new_email |> to("foo@example.com") |> from("me@example.com") |> subject("Welcome!!!") |> html_body("<strong>Welcome</strong>") |> text_body("welcome")
7. x = 1 # this is the "match" operator 1 = x # this is completely legit # lists [a, b, c] = [1, 2, 3] # maps %{id: id} = %{id: 1} %{id: id} = %{id: 1, name: "fido"} %{id: id} = %User{id: 1} # structs work too! # tuples {:ok, status, response} = {:ok, 200, "<h1>Dogs</h1>"}
8. {:ok, response} = HTTP.get("/dogs")
9. case HTTP.get("/dogs") do {:ok, response} -> Logger.info(response) {:error, error} -> Logger.error(error) end
10. defmodule DogService do def run do HTTP.get("/doggies") end def log({:ok, response}) do Logger.info(response) end def log({:error, error}) do Logger.error(error) end def log(_) do Logger.error("uhh... what happened?") end end DogService.run |> DogService.log
12. def give_treat(dog) do if dog do if dog.age > 5 "here ya go, #{dog.name}" else "here ya go, pup" end else "uhhh... no dog?" end end
13. def give_treat(nil), do: "uhh... no dog?" def give_treat(%{name: name, id: id}) when id > 5 do "here ya go, #{name}" end def give_treat(_) do "here ya go, pup" end
14. def give_treat(nil), do: "uhh... no dog?" def give_treat(id) when is_integer(id) do id |> find |> give_treat end def give_treat(%{age: age, name: name}) when age > 5 do "here ya go, #{name}" end def give_treat(_) do "here ya go, pup" end
16. case DB.insert(changeset) do {:ok, record} -> # woot woot! {:error, :timeout} -> # handle it {:error, changeset} -> # handle it end
18. def save(changeset) do case DB.insert(changeset) do {:ok, record} -> case ElasticSearch.sync(record) do {:ok, _, response} -> {:ok, record, response} {:error, status, response} -> {:error, status, response} end {:error, error} -> {:error, error} end end
19. with {:ok, record} <- DB.insert(changeset), {:ok, _, response} <- ElasticSearch.sync(record), do: {:ok, record, response}
21. iex> quote do: sum(1, 2, 3) {:sum, [], [1, 2, 3]}
22. iex> Macro.to_string(quote do: sum(1, 2 + 3, 4)) "sum(1, 2 + 3, 4)"
23. iex> number = 13 iex> Macro.to_string(quote do: 11 + number) "11 + number" iex> number = 13 iex> Macro.to_string(quote do: 11 + unquote(number)) "11 + 13"
24. assert "foo" =~ "bar" Assertion with =~ failed code: "foo" =~ "bar" lhs: "foo" rhs: "bar"
25. defmodule Example do def iif(test, a, b) do if test, do: a, else: b end end Example.iif(false, IO.puts("a"), IO.puts("b")) Example.iif(true, IO.puts("a"), IO.puts("b"))
26. a b a b
27. defmodule Example do defmacro iif(test, a, b) do quote do if unquote(test), do: unquote(a), else: unquote(b) end end end Example.iif(false, IO.puts("a"), IO.puts("b")) Example.iif(true, IO.puts("a"), IO.puts("b"))
28. b a
29. from fish in Fish, join: fisherman in assoc(fish, :fisherman), group_by: fisherman.name, select: [max(fish.length), fisherman.name]