I'm at the #Elixir/#Erlang devroom https://fosdem.org/2023/schedule/track/erlang_elixir_and_friends/

Let's be functional and parallel!

First speaker is late.

#TooManyBeers #FOSDEM

Speaker at least arrived. We start with the introduction "Elixir - Old wine in new casks"
Intro talk about Elixir/Erlang by Tonći Galić

The famous motto "Let it crash!" (suddenly, slides turn white)

#Elixir is a repackaging of an old idea. (A bit like Kotlin replacing Java.)

Ruby syntax, Erlang bytecode and virtual machine

There is of course a repository of libraries with a french TLD https://hex.pm/

Nw, "Introduction to Gleam
by building type-safe Discord bots on the BEAM" by Harry Bairstow

#Gleam is a programming language which can be compiled to BEAM (Erlang bytecode) or to Javascript.

#Shimmer is a library (written in Gleam) to talk to the proprietary centralized system Discord.

"Speak binary to me":
Learn the powers of binary pattern matching by Troels Brødsgaard

(First slide is only 0 and 1)

Elixir allos to define bainary values, type, sign, endianess (I failed o answer the qustion at the end of my Drink talk), etc.

iex(8)> <00::unsigned-integer-size(16)>>
<<1, 44>>

iex(10)> <00::unsigned-integer-size(16)-little>>
<<44, 1>>

And then you can match:

iex(6)> <<first::1, rest::7>> = <<0xFF>>
<<255>>
iex(7)> first
1

Example: talk to the #TBox temperature sensor. Asking its name

request = <<0xA::4,0::1, 0::3>>

Pattern matching the answer:

<<0xA::4,1:1, 0::3, name::bytes-12>> = reply

If it matches, the name will be in the "name" variable.

Fun site with challenges for the people who write network protocols: https://protohackers.com/

"LiveView keeps you warm!"
Building a knitting machine UI with Phoenix LiveView by Arjan Scherpenisse

(Phoenix is the Elixir framework for making Web sites)

A real hacker talk, starting with using an Arduino to control an old knitting machine, then designing a Web interface (with #LiveView) to drive it.

With LiveView, eveything is done on the server, you never write JavaScript, it is generated automaticallyt.

https://passapcanada.com/passap-e-6000-knitting-machines/

"Distributed music programming with Gleam, BEAM, and the Web Audio API" by Hayleigh Thompson

#Gleam, again? (This morning, I didn't know the existence of this language.)

So, I discover there is an API to allow Web applications to invade the sound space of the poor user https://www.w3.org/TR/webaudio/

"The Actor Model as a Load Testing Framework" by Nelson Vides

("Senior Erlang Consultant", that's a job title.)

What is the capacity of modern systems? What can they handle?

https://en.wikipedia.org/wiki/Tacoma_Narrows_Bridge_(1940)

"Unlike bridge engineers, we are lucky. We can load our software until it breaks."

First quote of Shakespare at a #FOSDEM talk.

The load-testing software is called AMOC (A Murder Of Crows, thanks to Shakespeare's Hamlet, Act 3,
Scene 2)

"Shorter feedback loops with Livebook" by Linus De Meyere

"Are you hungry?" [several hands raised]

"I cannot help with that but I can explain #Livebook"

#LIvebook is a tool to mix documentation and code (which can be evaluated). For learning or for creating small tutorials. You can then share them.

Demo with the :gen_tcp module. (With Murphy's help, to be sue it's a real demo.)

Quite convincing.

"Running Erlang and Elixir on microcontrollers with AtomVM"

How to run BEAM code on a 3 $ microcontroller by Davide Bettio @bettio [BEAM is Erlang bytecode]

AtomVM allows you to run ordinary/unmodified(but "don't do anything weird") Elixir/Erlang code on microcontrollers (not all of them! it works on ESP32, STM2, Raspberry Pi 2040, etc)

And the last talk of the Erlang/Elixir devroom, "Dealing with a Monster [#Ecto / daabase] Query",
a story of Elixir & optimization by Mackenzie Morgan

(Yet another talk with Beamer slides)

Max requsts/s : 700 % improvment

At the #Matrix talk, nice demo of #ThirdRoom, a VR system built on the top of Matrix. You can have a #metaverse without a GAFA or a stupid startup.

#FOSDEM