Haskell and Elm in Production

AN UNEXPECTED JOURNEY

Who am I?

• Senior Web Developer at LiveView Technology
• Father of two
• FP Programmer
• Love LoL (B5 for life)

Setting up the context

What we had

• CakePHP spaghetti mess
• Copy-Pasta of code everywhere
• Blend of JS libs meshed together
• Random jQuery

What we wanted

• Maintainability, Maintainability, Maintainability
• Multiple SPA apps to meet our different customer needs
• Unified cohesive frontend
• Properly architected backend

Skills we had

• CakePHP
• CodeIgniter
• Magento
• Angular 1.x
• jQuery
• Vanilla JS
• The ability to adapt

Questions?

Picking a frontend language

What we wanted

• Something that was "better" then just regular JS
• Framework that would not get in the way
• Something with good documentation

What we tried

• Elm
• Didn't feel a need to try anything else

Questions?

Picking a Backend Language

What we Originally wanted

• Able to handle changing requirements easily
• Something we were familiar with
• Simple, non-bloated framework
• Maintainability, Maintainability, Maintainability

So we chose:

PHP

But What framework?

Decided to look at micro-frameworks

• Bullet
• Slim
• Silex

Bulletphp

• Functional (Elm is functional)
• Used composer
• Had a good recommended project structure

• Didn't seem actively maintained
  • last commit was a few years ago
• Small community
• Didn't like php for websockets

If not PHP then what?

• NodeJS
• Go
• Rust
• Haskell
• Something else?

exploration

• Which had websocket support?
• Which had good mysql support?
• Which had a good community?
• Which had a "good" type system? 

Haskell

• Yesod has plugins for websockets
• Persistent allowed for type safe SQL
• Esqueleto allowed for type safe custom queries
• Community was very friendly, new book made learning much easier
  • http://haskellbook.com/

Questions?

Experience with ELM

Elm is its own paradigm

• Thinking OOP like causes more work
• Originally design to be a UI language
• The Elm Architecture
• Use types to guide design

What I Love

• No run-time exceptions
• No null
• Compiler is your friend
• Refactoring is amazing
• No "fancy" type system features

What is frustrating

• Direct JavaScript inter-opt

• Some compiler messages
• No "fancy" type system features

Community and Tooling

• Enforced Semantic Versioning
• Helpful Slack channel
• Elm-Format
• Young, but getting better every day

Questions?

Experience with Haskell

What surprised me

• That I don't need a PhD
• Can program at low and high levels
• Debugging is different due to lazy eval

Yesod

• Adheres to the Web Application Interface (WAI)
• Type safe URLs
• Type safe SQL
• Like a piecemeal "Ruby on Rails" framework

What I love

• Exceptions are used exceptionally
• Type safe business logic
• No null
• Can run it "interpretted", interpreted, or compiled
• Stack
• Types become micro unit tests

What is frustrating

• The seemingly huge emphasis on Monads
• Because of advanced types, compiler message can be cryptic
• Harder to learn if you already know OOP
  • Simple Made Easy - Rich Hickey

Community and Tooling

• Stack is amazing! (No more cabal hell)
• There are IRC channels and active slack channels in the Functional Programming slack
  • http://fpchat-invite.herokuapp.com/
  • https://www.haskell.org/irc
• Hoogle
  • http://hoogle.haskell.org/
• Hackage
  • https://hackage.haskell.org/
  • https://www.stackage.org/

Questions?