An introduction to Elixir, by someone who has fiddled around with it for a while

1. My Elixir HelWo lolrd
Why Elixir is the next big thing in tech world

2. Claudio D’Alicandro
AdEspresso
By Hootsuite
Twitter: @_cdali
Github: claudio-dalicandro

3. 19.000.000.000$
If you're thinking about WhatsApp, you're right... But what
is behind a 19,000,000,000 dollars idea?

4. A bit 'of numbers referring to WhatsApp
35
The engineers who worked for WhatsApp before
acquisition
450.000.000
WhatsApp users before
acquisition

5. Erlang and the BEAM
● Light-weight process
● No memory sharing
● Code hot-swap out of the box
● Actor modeling
● Battle tested virtual machine

6. My trouble with Erlang
● Prolog-inspired syntax
● Single assignment
sometimes is just as
problematic as
destructive assignment
● Strings-as-lists sucks

7. What if I told you that you can have all the advantages, and no flaws?

8. Elixir

9. The Toolbox

10. mix
Mix is a build tool that
provides tasks for
creating, compiling, and
testing Elixir projects,
managing its dependencies,
and more.

11. Mix
Create an Elixir project is simple:
$ mix new helwo_lorld
--module HW

12. exUnit
Unit testing framework for
Elixir.

13. ExUnit
● Simple macros help defining
readable tests
● ExUnit.DocTest implements
functionality similar to
Python’s doctest.
● ExUnit.Callbacks defines both
setup_all and setup callbacks,
as well as the on_exit/2
facility
● You can define the test as
asynchronous by adding “async:
true” in the use statement

14. Credo
A static code analysis
tool for the Elixir
language with a focus on
teaching and code
consistency.

15. Credo
● shows you refactoring
opportunities in your code
● shows complex or duplicated
code fragments
● warns you about common
mistakes
● shows inconsistencies in your
naming scheme
● helps you enforce a desired
coding style

16. The Language

17. Data types

18. Elixir Basic types
● Integer
● Float
● Boolean
● Atom
● String
● List
● Tuple

19. Keyword lists
A keyword list is a list of tuples

20. Maps
A map can be “updated”
A map can be destructured through pattern matching

21. Pattern Matching

22. What is the pattern matching?
Actually, your “=” operator sucks.

23. Destructuring
You can use the pattern matching to
destructure the input of a function

24. Pattern matching usages

25. Guards
Clauses also allow extra
conditions to be specified
via guards

26. Polymorphism
Finally, it is important to specify that by using pattern
matching you can implement polymorphism, indeed, you can set
the same function multiple times, so as to cover different
patterns with different behaviors

27. Parallel processing

28. Spawn a process
In Elixir, all code runs
inside processes. Processes
are isolated from each
other, run concurrent to one
another and communicate via
message passing. Processes
are not only the basis for
concurrency in Elixir, but
they also provide the means
for building distributed and
fault-tolerant programs.

29. Link and Monitoring
The majority of times we
spawn processes in Elixir,
we spawn them as linked
processes.
When two process are linked
the failure in one process
propagates to the other.
Finally, we can set up a
monitor so that the parent
process will receive a
notification every time a
child exits

30. Why processes are so important?
Obviously the processes are
primarily a tool to perform
parallel computations, but thanks
to the BEAM and the infinite number
of processes that can run on the
inside, they have become something
more…

31. Actor Modeling

32. OTP
No, this not means one time
password
The Open Telecom Platform
is a collection of
Middleware, libraries and
tools

33. Tasks, Agents, GenServers, GenEvents...
Tasks
meant to execute
one particular
action throughout
their lifetime,
often with little
or no
communication with
other processes.
store state that
must be accessed
from different
processes
Agents
standard set of
interface
functions,include
functionalities
for tracing and
error reporting
GenServers
event manager
process with an
arbitrary number
of event handlers
which are added
and deleted
dynamically
GenEvents

34. Actor Modeling

35. Questions?