F# and its 11 features

1. F# and its 11 features Guanru Li 2011 ACM class

2. F# is … ... a programming language.

3. F# is … ... a functional programming language

4. F# is … ... a functional programming language for .NET

5. F# is … ... a functional and object oriented programming language for .NET

6. F# is … ... a functional, object oriented and imperative programming language for .NET

7. F# is … ... a multi-paradigm programming language for .NET

8. F# is … ...a multi-paradigm programming language for .NET, ideally suited for technical, symbolic and algorithmic applications

9. F#

10. Why named F#? • C# • Functional programming

11. Hello F#, Hello n factorial printfn "Hello F#!“ letrec factorial n = match n with | 0 -> 1 | _ -> n * factorial(n - 1)

12. Feature 1 of 11 • Functional programming let f (g: int -> int) y = g y let increment x = x + 1 let a = f increment 100 • Lambda expression let f (g: int -> int) y = g y let a = f (fun x -> x + 1) 100

13. Feature 2 of 11 • Compose the functions! let function1 x = x + 1 let function2 x = x * 2 let h = function1 >> function2 let a = h 100

14. Feature 3 of 11 • Collection types for immutable data • Usage: ??

15. Feature 4 of 11 • Pattern matching (x is a list) let length x = match x with | [] -> “0” | [ _ ] -> “1” | [ _; _ ] -> “2” | _ -> “Too Long!”

16. Feature 5 of 11 • Discriminated unions type Shape = | Circle of float | Square of double let area myShape = match myShape with | Circle r -> 3.14*r*r | Square r -> s*s

17. Feature 6 of 11 • Interactive programming

18. Feature 7 of 11 • Lazy computations & lazy evaluation let x = 10 let result = lazy (x + 10) do something printfn "%d" (result.Force())

19. Feature 8 of 11 • Object oriented • Class & inherit • Single inheritance

20. Feature 9 of 11 • Imperative programming • Like C, C++, Java

21. Feature 10 of 11 • Generics and type inference let makeList a b = [a; b] makeList<int> 1 2 let function1 a = a + 1

22. Feature 11 of 11 • Asynchronous workflows • ？？

24. Reference • http://en.wikipedia.org/wiki/F_Sharp_(programming_language) ---- wikipedia F sharp • http://msdn.microsoft.com/zh-cn/library/ dd233181 ---- MSDN F# reference • http://developer.51cto.com/art/201004/192870.htm ---- 51CTO.com F# new features

25. Q&A