Functional programming

• Why:
• General sateless tendency: cloud & scaling
• No locks (multi-thread)
• Easy reading
• Easy testing
• JavaScript boom?
• How: 
• Pure functions (no side-effects)
• Immutability
• Composition (not inheritance)
• Deferred execution
• Currying
•  ...
• Related: funcional reactive programming.

Why functional programming matters:
https://www.cs.kent.ac.uk/people/staff/dat/miranda/whyfp90.pdf

FP Languages

• Erlang
• Haskell
• OCami
• LISP
• Scheme
• Standard ML
• Wolfram
• Frege (JVM): https://github.com/Frege/frege
• Clojure (JVM)

Hybrid Languages

• Scala (JVM)
• F#