1 / 12

Functional Programming

Functional Programming. Theoretical foundation Church’s - calculus expressions and evaluation rules Characteristics Single assignment variables (pure FP) Recursion Rule-based and pattern matching (ML, Haskell, F#) High-order functions Lazy evaluation (Haskell)

tamah
Download Presentation

Functional Programming

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Functional Programming • Theoretical foundation • Church’s -calculus • expressions and evaluation rules • Characteristics • Single assignment variables (pure FP) • Recursion • Rule-based and pattern matching (ML, Haskell, F#) • High-order functions • Lazy evaluation (Haskell) • Meta-programming (Scheme) by Neng-Fa Zhou

  2. F# • A hybrid language • ML-like functional programming • Iimperative programming • OOP • Scripting • Runs on the .NET platform • It is possible to use any .NET library from F# • It is possible to use F# library from other .NET languages such as C# • Available for free • Works with Visual Studio • Standalone fsharp interpreter fsi by Neng-Fa Zhou

  3. F# vs. Prolog • Common characteristics • Repetition via recursion • High-order • Garbage collection • Differences • Strongly typed vs. dynamically typed • Functional vs. relational • Prolog supports unification and backtracking by Neng-Fa Zhou

  4. Types • int -- 123, -10 • float -- 122.123, 0.23e-10 • bool -- true, false • char -- ‘a’ • string -- “abc” • list -- [1;2;3], 1::[2;3], [1]@[2;3] • array -- [|1;2;3|] • tuple -- ("abc",1,true) • union -- type MyBool = | True | False by Neng-Fa Zhou

  5. Operators • +, -, *, /, % • &&, ||,not • =, <>, <, >, <=, >= by Neng-Fa Zhou

  6. let • let x = 1+2+3 • let f x y = x+y • let f (x,y) = x+y • let rec f n = if n = 0 then 1 else n*(f n-1) by Neng-Fa Zhou

  7. Pattern Matching let rec len lst = match lst with | [] -> 0 | _::lst1 -> 1+len lst1 by Neng-Fa Zhou

  8. Tail Recursion let rec len1 ac lst = match lst with | [] -> ac | (_::lstr) -> len1 (ac+1) lstr let len lst = len1 0 lst by Neng-Fa Zhou

  9. Unions type SExp = | O | S of Sexp let rec sum x y = match x with | O -> y | S x1 -> S(sum x1 y) by Neng-Fa Zhou

  10. Unions (Cont.) type TreeInt = | Void | Leaf of int | Node of int*TreeInt*TreeInt let rec count tree = match tree with | Void -> 0 | Leaf(_) -> 1 | Node(_,left,right) -> 1+ (count left) + (count right) by Neng-Fa Zhou

  11. High-order Functions let succ = fun x -> x+1 List.map succ [1;2;3] List.map (fun x -> x+1) [1;2;3] by Neng-Fa Zhou

  12. map and fold let rec map f lst = match lst with | [] -> [] | (car :: cdr) -> (f car)::(map f cdr) let rec fold f lst acc = match lst with | [] -> acc | (car :: cdr) -> f car (fold f cdr acc) let rec foldl f lst acc = match lst with | [] -> acc | (car :: cdr) -> foldl f cdr (f car acc) by Neng-Fa Zhou

More Related