This document discusses functional programming and its use for web development. It introduces the Elm and Elixir languages as examples of pure functional languages that can handle input/output without side effects. Elm is described as a good choice for building mobile clients since it avoids CSS, HTML, and JavaScript. The document also presents serverless architecture as an option using Elm, with the client communicating directly with a shared database. It provides links to resources on Elm and the Phoenix framework for Elixir web development. Overall, the document promotes functional programming and Elm/Elixir as trends for building scalable and maintainable web applications.

1. Functional Programming and
Web
Umur Ozkul
umur.ozkul@gmail.com
http://www.slideshare.net/publitory/elm-elixir-
functional-programming-and-web

2. Startup Crisis
● Competition
● Too many bugs
● High Response Time
● Scaling to billion users
● Metaprogramming & Beating the averages
– http://paulgraham.com/avg.html
If there is a nail then every tool is a hammer
Join Formula 1 with a donkey ?

3. Companies
https://github.com/doomspork/elixir-companies
Note Pinterest

4. Why Functional Programming is
Trending
No Side Effects
No runtime errors
Evertything is testable
If each user reports 1 bug then think about
10,000,000 users
Better compilers
Concurrency

5. Why now?
Handling External World and IO
Elm & Elixir are pure functional langages that
handle this problem without getting dirty
Pure functionality leads to efficient compilers
Over simplified view :
fn([event1 … eventN])

6. Elm
No CSS, No Html, No Javascript
Visual components, like OO but better
Good for mobile clients

7. Serverless Architecture with
Elm
Nowadays every client is a powerful computer
No need for server side processing
We just need authenticated access to shared
data
No more scalability problem

8. Serverless Architecture with
Elm
Client Server Database
Elm Client
Authenticated
Shared Data

9. Elm Links
● Language http://elm-lang.org/
● Application Architecture
● https://www.elm-tutorial.org/en/
● Arcade Game Examples http://builtwithelm.co/
● Elm Component Example
● https://github.com/umuro/elm-mdl-counter-pair
● Mobile Widgets https://debois.github.io/elm-mdl/
Use Haskell syntax highlighting…
Refer to Phoenix installation if you’re in trouble
with node.js installation

10. Erlang VM
Battle Tested
Distributed processing on the phone satellites
around the world
Best context switching performance
Born in 1987 by Ericsson
We must develop our own language with the
desirable features of Lisp, Prolog and Parlog,
but with concurrency and error recovery built
into the language

11. Elixir
Good for Servers
Threads, no processes
Erlang VM : Concurrency is natural
Microseconds, not milliseconds

12. Elixir Phoenix Links
● http://elixir-lang.org/install.html
● http://www.phoenixframework.org/docs/installation
● https://wiki.postgresql.org/wiki/Detailed_installation_guides
● http://www.phoenixframework.org/docs/up-and-running
Do not study Elixir before studying Phoenix

13. Blorg
$ mix phoenix.gen.json API.V1.Article articles title:string body:text
$ mv web/models/api/v1/article.ex web/models/
$ mix ecto.migrate
$ mix test
Challenge :
Implement (+) button to add new blog
articles
https://github.com/umuro/blorg

14. Last Word : Endurance
● Walk 7km per day
● Do not sit at least 3 hours per day
● 2 hours of weight lifting per week
Or start to complain that you cannot program
anymore…
http://www.slideshare.net/publitory/elm-elixir-
functional-programming-and-web