Introduction to Functional Programming

First part of the first Fun(Lx) meetup, with a very brief overview of FP concepts, to provide a motivation for the Erlang and Scala talks.

Transcript

1. @funlx #funlx
2. First Fun(Lx) meetup!
3. Functional Programming 1936: λ-calculus - Alonzo Church 1960: LISP - John McCarthy 197*: ML - Robin Milner 1975: Scheme - Guy Steele 1985: Miranda - David Turner 1986: Erlang - Joe Armstrong 1990: Haskell - Simon Peyton Jones 2003: Scala - Martin Odersky 2005: F# - Microsoft 2007: Clojure - Rich Hickey 2012: Elixir - José Valim
4. What is Functional Programming?
5. What is Functional Programming? String INT
6. What is Functional Programming? Length = String INT
7. What is Functional Programming? Length = String INT Int Bool
8. What is Functional Programming? Length = String INT zero? = Int Bool
9. What is Functional Programming? Length = String INT zero? = Int Bool zero? . Length = Bool String
10. What is Functional Programming? Length = String INT zero? = Int Bool empty? = zero? . Length = Bool String
11. What is Functional Programming? Size = [ … ] INT zero? = Int Bool empty? = zero? . SIZE = Bool [ … ]
12. What is Functional Programming? F = * INT zero? = Int Bool empty? (F) = zero? . F = Bool * F
13. What is Functional Programming?
14. What is Functional Programming? ⌚
15. What is Functional Programming? ⌚ 19:35
16. What is Functional Programming? ⌚ 19:36
17. What is Functional Programming? ⌚ 19:33
18. What is Functional Programming? ⌚
19. What is Functional Programming? ⌚
20. What is Functional Programming? 3 “Ham” “Derp”
21. What is Functional Programming? def do_something(x, y) z = y.map {|i| i + x } expensive_computation(z) z end
22. Functional Programming composition of functions as the building block of computation higher order functions focus on expressions vs statements referential transparency avoid mutable state lazy evaluation
23. FP outside FP: Blending OO and FP
24. FP outside FP: Blending OO and FP No side effects Functional Stateful Imperative
25. FP outside FP: Blending OO and FP Wat
26. FP outside FP: Underscore.js
27. FP outside FP: Underscore.js
28. FP outside FP: Functional Ruby
29. FP outside FP: Functional Ruby
30. FP outside FP: Java 8 Lambdas
31. Questions?