An introduction to some of my favorite elixir features. https://www.promptworks.com/

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]