ERLANG, LFE, JOXA & ELIXIR

Established and

Emerging Languages in

the Erlang Ecosystem

Let’s talk about computers.

many processors

in a network

inside an even

bigger network

and none of it’s

reliable

and also it’s spread across the

globe

Our challenge as engineers is to hide the complicated details of all of this.

Let’s talk about Erlang.BEAM

Bogdan/jörn’s

Erlang

Abstract

Machine

Concurrent

Concurrent Soft Real-Time

Concurrent Soft Real-Time Throughput Optimized

Concurrent Soft Real-Time Throughput Optimized Embeddable

So we should all start using Erlang right away, yes?

Well…

Let’s talk about style.

Miles Davis

Miles Daviscool

Miles Daviscool spare

Miles Daviscool spare deliberate

Miles Daviscool spare deliberate flawless

Miles DavisSought to make an individual, new sound.

John Coltrane

John Coltrane

avant guard

John Coltrane

avant guard complex

John Coltrane

avant guard complex chaotic

John Coltrane

avant guard complex chaotic blemished

John Coltrane

Sought the transcendent

through music.

Thelonious Monk

Thelonious Monk

unorthodox

Thelonious Monk

unorthodox eccentric

Thelonious Monk

unorthodox eccentric

discordant

Thelonious Monk

unorthodox eccentric

discordant perfect

Thelonious Monk

Made music like a fish swims in water

I’m going to compare

programming languages.

These languages are not so dissimilar.

This is not a life or death

matter.

This is a matter of right tool, right job.

Every language has an intrinsic philosophy of “good software”.

The language designers’ choices influence what a language is most naturally useful for.

Sometimes a design goal is explicit.

Erlang

Soft real-time, concurrent and fault tolerant systems.

Subsystems may fail but the service as a whole remains online.

Failures cause sub-system restarts.

Restarts put the system back in a well-known state: prefer faults over error handling.

Let it crash!

Language features make crashes more likely.

Pattern Matching

No assignments:

Failed matches cause crashes.

Process Linking

Faults cascade up the process hierarchy.

Traps exist to survive child crashes but they are not on by default.

Strict process isolation.

State changes are effected only through message passing.

Processes are sequential internally, concurrent to one

another.

L F ELisp Flavored Erlang

Maintains semantic

equivalence to Erlang.

Lisp-2, Macros &

Homoiconicity

A REPL, not just a

shell.

Erlang, in Lisp

Clothing

Let it crash!

Joxa

Lisp-1, Macros &

Homoiconicity

A lisp that happens to run on

BEAM

Elixir

Solves the “Expression”

problem

Protocols

Streams / Iterables

Infix

Operators

Multiple function invocation styles

Metaprogramming

Multi-Assignments

Pattern Matching is non-default. Must use a prefix character to match.

Defaults callbacks for OTP

Behaviours

Which of these languages are production ready?

What’s your risk tolerance?

LFE 367 commits August 22, 2008 updated weekly 14 contributors

Joxa 470 commits November 25, 2011 updated monthly 8 contributors

Elixir 7618 commits January 9, 2011 updated daily 168 contributors

Erlang 14,273 commits Estd.1986 updated daily

227 contributors

Complexity

Complexity

Erlang

Complexity

Erlang LFE

Complexity

Erlang ElixirLFE

Software projects go through three stages: !

• exploration • stable development • maintenance

Experimentation

Stable Development

Maintenance

Different phases of the life-cycle express different needs.

Experimental: “Move fast, break stuff.”

Stable: “Go fast and mostly work.”

Maintenance: “Move slow, build things.”

“Expressivity”, which is a boon while prototyping, can be a curse in more stable environments.

“Intentional” languages may be too cumbersome in an environment of complete unknowns.

Complexity

C++Erlang ElixirLFE

C++Erlang ElixirLFE

None of the BEAM languages abandon what makes Erlang great (especially not Erlang).

Elixir targets the experimental, very beginnings of stable.

LFE targets the tail end of experimental, beginning to mid of stable.

Erlang is a stable and maintenance stage sort of language.

Experimentation

Stable Development

Maintenance

Elixir

LFE

Erlang

Questions? <3

Thank you! @bltroutwine