The document discusses making Swift more functional by adding features like list comprehensions, tail call optimization, and making tail call optimization guaranteed. It highlights the benefits of functional programming like writing clearer code, easier concurrency, and reduced complexity. It also discusses specific functional programming concepts in Swift like recursion and tail calls, providing examples of how tail call optimization can prevent stack overflows. The presenter advocates contributing to the Swift open source project to further enhance its support for functional programming once it becomes open source.

1. Making Swift Even
More Functional
- Swift Summit

2. Hello, I’m
Veronica Ray!

3. Swift is great, but it
could be better
Time to make
change is now

4. –The Recurse Center User’s Manual
“Be rigorous. Understand
how and why your code
works. Understand your
tools. If you're working with
a framework (like Sinatra or
Flask), learning to use it is
just scratching the surface.
Go deeper. Learn how it
works.”

5. – Functional Programming In Swift
“Functional programmers
emphasize that each
program can be repeatedly
broken into smaller and
smaller pieces; all these
pieces can be assembled
using function application
to define a complete
program.”

6. – Functional Programming In Swift
“Functional programming…
emphasizes the importance
of programming with values,
free of mutable state or
other side effects.”

7. CLASS
VS
STRUCT

8. WHY FUNCTIONAL?
•Helps you write clear
and concise code
•Makes concurrency
easier
•Reduces complexity

9. vs

10. SIMPLICITY

12. COMPARED TO
SCALA

14. Too many
custom
operators and
not opinionated
enough

15. FP IN SWIFT
•list
comprehensions
•tail call
optimization

16. FP IN SWIFT
•list
comprehensions
•tail call
optimization

17. LIST
COMPREHENSIONS

18. POWERFUL

19. PYTHON

20. PYTHON

21. BYTE CODE

22. PYTHON FOR LOOP

23. BYTE CODE IS
23 LINES!

24. vs

25. BYTE CODE IS THE SAME

26. SPELLING CORRECTOR

27. CONCISENESS
Reading code
Writing code

28. ADDING IT TO
SWIFT

29. FP IN SWIFT
•list
comprehensions
•tail call
optimization

30. RECURSION

31. TAIL CALL

32. TAIL RECURSIVE CALL

33. STACK TRACE
(fact 3)
(fact-tail 3 1)
(fact-tail 2 3)
(fact-tail 1 6)
(fact-tail 0 6)
6

34. NOT TAIL RECURSIVE

35. STACK TRACE
(fact 3)
(* 3 (fact 2))
(* 3 (* 2 (fact 1)))
(* 3 (* 2 (* 1 (fact 0))))
(* 3 (* 2 (* 1 1)))
(* 3 (* 2 1))

36. TAIL CALL
OPTIMIZATION

37. NOT
GUANRANTEED

38. SWIFT CODE

39. BYTE CODE
jne to the label containing the
conditional jump

40. BLOW OUT THE STACK

41. HOPE?

42. CHANGE YOUR
BYTECODE
CHANGE YOUR LIFE

43. RECURSION KILLS

44. RADAR

45. LEARN MORE

46. •Functional Swift Conference
•Open Radar
•Dev Forums
•Twitter
•Natasha The Robot’s Blog

47. WHEN SWIFT GOES
OPEN SOURCE

48. TIME TO MAKE
CHANGE IS NOW