February 2020 we had a great Elixir Meetup at Montel Intergalactic mothership. These are the slides from our own Jukka Välimaa's presentation. The code and slides from our guest speaker Thomas O'Rourke's presentation "Elixir, safe yet practical" can be found here: https://github.com/tomjoro/elixir_safe_practical Also, Mikko Ahlroth's presentation can be found here: https://docs.google.com/presentation/d/1l2xoJhcFhNi0OfnQq5sVhfDUSZJHHPJnc1YqSWPVaSw/edit?usp=sharing, and the code here: https://gitlab.com/code-stats/code-stats/-/blob/master/lib/code_stats/legal_terms.ex.

1. Why I love Elixir
One Pythonista’s perspective
By Jukka Välimaa

2. Community & tools
● Very friendly and positive community
● Developer-friendly tooling

3. Functional
● Immutable data structures
● Pipe operator:
" Elixir... rocks "
|> String.upcase()
|> String.replace(“...”, “”)
|> String.split()
[“ELIXIR”, “ROCKS”]

4. Pattern matching
iex> {a, b, c} = {:hello, "world", 42}
{:hello, "world", 42}
iex> a
:hello
iex> b
"world"
iex> {:ok, [hello: a]} = {:ok, [hello: "world"]}
iex> a
"world"

5. Pattern matching
case File.read("path/to/file") do
{:ok, contents} -> IO.puts("found file: #{contents}")
{:error, reason} -> IO.puts("missing file: #{reason}")
end

6. Pattern matching
def first_element([head | _tail]) do
head
end
def first_element([]) do
nil
end

7. Sigils
regex = ~r”foo|bar”
Could also be written as
regex = ~r(foo|bar)
regex = ~r”foo|bar”
regex = ~r|foo|bar|

8. ● Strings
○ ~s(this is a string with "double" quotes, not 'single' ones)
● Dates
○ d = ~D[2020-02-27]
● Times
○ t = ~T[18:15:00]
● Datetimes
○ Dt = ~N[2020-02-27 18:15:07]

9. Concurrency model
● Easy concurrency and parallelism
● Erlang/Elixir concurrency models is based on lightweight threads of execution called
processes
● In a way, Erlang virtual machine plays the role of operating system

10. import asyncio
import asyncpg
async def run():
conn = await asyncpg.connect(user='user', password='password',
database='database', host='127.0.0.1')
values = await conn.fetch('''SELECT * FROM mytable''')
await conn.close()
return values
loop = asyncio.get_event_loop()
values = loop.run_until_complete(run())
def run() do:
{:ok, pid} = Postgrex.start_link(hostname: "127.0.0.1”, username: "user", password:
“password", database: "database")
values = Postgrex.query!(pid, "SELECT * FROM mytable", [])
GenServer.stop(pid)
values
end
task = Task.async(run)
values = Task.await(task)

11. From Saša Jurić’s talk “The Soul of Erlang and Elixir”

12. Phoenix LiveView
● Uses Phoenix sockets to push changes in HTML to browser
● Removes need for client-side JavaScript for several use cases

13. Thank you!
● Do put up topics as lightning talk
● Montel might have work with Elixir projects in
the future; feel free leave me your contact info
or send email to elina@montel.fi