Downloaded 76 times
![public class ReferentiallyOpaque {
private int x = 0;
static int f(int y) {
return x += y;
}
public static void main(String[] args) {
ReferentiallyOpaque ro = new ReferentiallyOpaque();
System.out.println(ro.f(5));
System.out.println(ro.f(5));
}
}](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/85/Functional-programming-basics-11-320.jpg)
![public class ReferentiallyOpaque {
private int x = 0;;
static int f(int y) {
return x += y;
}
public static void main(String[] args) {
ReferentiallyOpaque ro = new ReferentiallyOpaque();
System.out.println(ro.f(5));
System.out.println(ro.f(5));
}
}
5
10](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/85/Functional-programming-basics-12-320.jpg)
![public class Example {
public static void main(String[] args) {
StringBuffer buffer = new StringBuffer("Hello World");
System.out.println(buffer.reverse());
System.out.println(buffer.reverse());
}
}](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/85/Functional-programming-basics-13-320.jpg)
![public class Example {
public static void main(String[] args) {
StringBuffer buffer = new StringBuffer("Hello World");
System.out.println(buffer.reverse());
System.out.println(buffer.reverse());
}
}
dlroW olleH
Hello World](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/85/Functional-programming-basics-14-320.jpg)
![public class Example {
public static void main(String[] args) {
StringBuffer buffer = new StringBuffer("Hello World");
StringBuffer s1 = buffer.reverse();
StringBuffer s2 = buffer.reverse();
System.out.println(s1 + " " + s2);
}
}](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/85/Functional-programming-basics-15-320.jpg)
![public class Example {
public static void main(String[] args) {
StringBuffer buffer = new StringBuffer("Hello World");
StringBuffer s1 = buffer.reverse();
StringBuffer s2 = buffer.reverse();
System.out.println(s1 + " " + s2);
}
}
Hello World Hello World](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/85/Functional-programming-basics-16-320.jpg)
![Modifying data
Immutable
static List<Integer> addToList(List<Integer> integers, int a) {
integers.add(a);
return integers;
}
let addToList list a =
list @ [a]
> let g = [1;2;3;];;
val g : int list = [1; 2; 3]
> addToList g 4;;
val it : int list = [1; 2; 3; 4]
> g;;
val it : int list = [1; 2; 3]
>
http://4.bp.blogspot.com/_RpRScqAI8e4/SbNPgumsqPI/AAAAAAAAAK4/ZK8ZsfKJCmQ/s400/wolverine+hugh+jackman.jpg](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/85/Functional-programming-basics-22-320.jpg)
![Lazy Evaluation
“Ability to invoke expressions only when its value is needed.”
static void Main(string[] args)
{
var lazy = new Lazy<int>(() =>
{
Console.WriteLine("calculating...");
return 6 * 7;
});
Console.WriteLine(lazy.Value);
Console.WriteLine(lazy.Value);
}](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/85/Functional-programming-basics-32-320.jpg)
![Lazy Evaluation
“Ability to invoke expressions only when its value is needed.”
static void Main(string[] args)
{
var lazy = new Lazy<int>(() =>
{
Console.WriteLine("calculating...");
return 6 * 7;
});
Console.WriteLine(lazy.Value);
Console.WriteLine(lazy.Value);
}
calculating...
42
42](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/85/Functional-programming-basics-33-320.jpg)
![Lazy Evaluation
“Memoization”
function Lazy_Memoized(def) {
var cache = [];
return function(i) {
return (i in cache) ? cache[i] :
(cache[i] = def.call(arguments.callee, i));
};
}
var factorial = new Lazy_Memoized(function(i) {
return i <= 1 ? i : i * this(i - 1);
});
factorial(6)](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/85/Functional-programming-basics-34-320.jpg)
![public class ReferentiallyOpaque {
private int x = 0;
static int f(int y) {
return x += y;
}
public static void main(String[] args) {
ReferentiallyOpaque ro = new ReferentiallyOpaque();
System.out.println(ro.f(5));
System.out.println(ro.f(5));
}
}](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/75/Functional-programming-basics-11-2048.jpg)
![public class ReferentiallyOpaque {
private int x = 0;;
static int f(int y) {
return x += y;
}
public static void main(String[] args) {
ReferentiallyOpaque ro = new ReferentiallyOpaque();
System.out.println(ro.f(5));
System.out.println(ro.f(5));
}
}
5
10](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/75/Functional-programming-basics-12-2048.jpg)
![public class Example {
public static void main(String[] args) {
StringBuffer buffer = new StringBuffer("Hello World");
System.out.println(buffer.reverse());
System.out.println(buffer.reverse());
}
}](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/75/Functional-programming-basics-13-2048.jpg)
![public class Example {
public static void main(String[] args) {
StringBuffer buffer = new StringBuffer("Hello World");
System.out.println(buffer.reverse());
System.out.println(buffer.reverse());
}
}
dlroW olleH
Hello World](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/75/Functional-programming-basics-14-2048.jpg)
![public class Example {
public static void main(String[] args) {
StringBuffer buffer = new StringBuffer("Hello World");
StringBuffer s1 = buffer.reverse();
StringBuffer s2 = buffer.reverse();
System.out.println(s1 + " " + s2);
}
}](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/75/Functional-programming-basics-15-2048.jpg)
![public class Example {
public static void main(String[] args) {
StringBuffer buffer = new StringBuffer("Hello World");
StringBuffer s1 = buffer.reverse();
StringBuffer s2 = buffer.reverse();
System.out.println(s1 + " " + s2);
}
}
Hello World Hello World](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/75/Functional-programming-basics-16-2048.jpg)
![Modifying data
Immutable
static List<Integer> addToList(List<Integer> integers, int a) {
integers.add(a);
return integers;
}
let addToList list a =
list @ [a]
> let g = [1;2;3;];;
val g : int list = [1; 2; 3]
> addToList g 4;;
val it : int list = [1; 2; 3; 4]
> g;;
val it : int list = [1; 2; 3]
>
http://4.bp.blogspot.com/_RpRScqAI8e4/SbNPgumsqPI/AAAAAAAAAK4/ZK8ZsfKJCmQ/s400/wolverine+hugh+jackman.jpg](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/75/Functional-programming-basics-22-2048.jpg)
![Lazy Evaluation
“Ability to invoke expressions only when its value is needed.”
static void Main(string[] args)
{
var lazy = new Lazy<int>(() =>
{
Console.WriteLine("calculating...");
return 6 * 7;
});
Console.WriteLine(lazy.Value);
Console.WriteLine(lazy.Value);
}](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/75/Functional-programming-basics-32-2048.jpg)
![Lazy Evaluation
“Ability to invoke expressions only when its value is needed.”
static void Main(string[] args)
{
var lazy = new Lazy<int>(() =>
{
Console.WriteLine("calculating...");
return 6 * 7;
});
Console.WriteLine(lazy.Value);
Console.WriteLine(lazy.Value);
}
calculating...
42
42](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/75/Functional-programming-basics-33-2048.jpg)
![Lazy Evaluation
“Memoization”
function Lazy_Memoized(def) {
var cache = [];
return function(i) {
return (i in cache) ? cache[i] :
(cache[i] = def.call(arguments.callee, i));
};
}
var factorial = new Lazy_Memoized(function(i) {
return i <= 1 ? i : i * this(i - 1);
});
factorial(6)](https://image.slidesharecdn.com/functionalprogramming-110126002217-phpapp01/75/Functional-programming-basics-34-2048.jpg)
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Similar to Functional programming basics
Functional programming basics
- 1. ______ _ _ _ | ____| | | (_) | | | |__ _ _ _ __ ___| |_ _ ___ _ __ __ _| | | __| | | | '_ / __| __| |/ _ | '_ / _` | | | | | |_| | | | | (__| |_| | (_) | | | | (_| | | |_| __,_|_| |_|___|__|_|___/|_| |_|__,_|_| _____ _ | __ (_) | |__) | __ ___ __ _ _ __ __ _ _ __ ___ _ __ ___ _ _ __ __ _ | ___/ '__/ _ / _` | '__/ _` | '_ ` _ | '_ ` _ | | '_ / _` | | | | | | (_) | (_| | | | (_| | | | | | | | | | | | | | | | (_| | |_| |_| ___/ __, |_| __,_|_| |_| |_|_| |_| |_|_|_| |_|__, | __/ | __/ | |___/ |___/ ____ __ __ __ __ __ ____ __ _ _ __ ____ __ ____ __ __ _ ( _ / _ ( ) / _ _( )( ) ( / _ ( / ) / ( / _ ( _ / _ ( ( ) _ (/ / (_// / ) )( ) D (/ / / ( O )) D (/ ) // / / (____/_/_/____/_/_/____/(__) (____/_/_/_)(_/ __/(____/_/_/(___)_/_/_)__)
- 2.
- 3.
- 4. Functional Programming isa style whose underlying model of computation is the function. f(x)
- 5. Referential Transparency Higher Order functions Lazy Evaluation Pattern Matching http://picasaweb.google.com/damodaran.balaji/DevCampChennaiJuly2010#5493004664487949618
- 6.
- 7. Referential Transparency Higher Orderfunctions Lazy Evaluation Pattern Matching
- 8. Referential Transparency “Equals can be replaced with equals” http://2.bp.blogspot.com/_DS3VD3b2euI/TRIcIUzduDI/AAAAAAAAAGA/Xp2E6kPxZCc/s1600/Pascal+the+chameleon+from+tangled+rapunzel+disney+cartoon.jpg
- 9. Referential Transparency “Equals canbe replaced with equals” f(x) = g(x) + 5 h(x) = x * f(x)
- 10. Referential Transparency “Equals canbe replaced with equals” f(x) = g(x) + 5 h(x) = x * f(x) h(x) = x * (g(x) + 5)
- 11. public class ReferentiallyOpaque{ private int x = 0; static int f(int y) { return x += y; } public static void main(String[] args) { ReferentiallyOpaque ro = new ReferentiallyOpaque(); System.out.println(ro.f(5)); System.out.println(ro.f(5)); } }
- 12. public class ReferentiallyOpaque{ private int x = 0;; static int f(int y) { return x += y; } public static void main(String[] args) { ReferentiallyOpaque ro = new ReferentiallyOpaque(); System.out.println(ro.f(5)); System.out.println(ro.f(5)); } } 5 10
- 13. public class Example{ public static void main(String[] args) { StringBuffer buffer = new StringBuffer("Hello World"); System.out.println(buffer.reverse()); System.out.println(buffer.reverse()); } }
- 14. public class Example{ public static void main(String[] args) { StringBuffer buffer = new StringBuffer("Hello World"); System.out.println(buffer.reverse()); System.out.println(buffer.reverse()); } } dlroW olleH Hello World
- 15. public class Example{ public static void main(String[] args) { StringBuffer buffer = new StringBuffer("Hello World"); StringBuffer s1 = buffer.reverse(); StringBuffer s2 = buffer.reverse(); System.out.println(s1 + " " + s2); } }
- 16. public class Example{ public static void main(String[] args) { StringBuffer buffer = new StringBuffer("Hello World"); StringBuffer s1 = buffer.reverse(); StringBuffer s2 = buffer.reverse(); System.out.println(s1 + " " + s2); } } Hello World Hello World
- 17.
- 18. • Looping • File I/O • Modify Data • Do more than one thing? http://paulafanclub.com/wp-content/uploads/2010/12/confused.jpg
- 19. Looping static int factorial(intnumber) { int f = 1; for (int i = number; i > 0; i--) f = f * i; return f; }
- 20. Looping Recursion static int factorial(int number) { int f = 1; for (int i = number; i > 0; i--) f = f * i; return f; } static int factorial(int number) { return (number == 1) ? number : number * factorial(number - 1); } http://www.shrink4men.com/wp-content/uploads/2010/11/dog-chasing-its-tail.jpg
- 21. Modifying data static List<Integer>addToList(List<Integer> integers, int a) { integers.add(a); return integers; } Mutable data structures
- 22. Modifying data Immutable static List<Integer> addToList(List<Integer> integers, int a) { integers.add(a); return integers; } let addToList list a = list @ [a] > let g = [1;2;3;];; val g : int list = [1; 2; 3] > addToList g 4;; val it : int list = [1; 2; 3; 4] > g;; val it : int list = [1; 2; 3] > http://4.bp.blogspot.com/_RpRScqAI8e4/SbNPgumsqPI/AAAAAAAAAK4/ZK8ZsfKJCmQ/s400/wolverine+hugh+jackman.jpg
- 23. Referential Transparency Higher Orderfunctions Lazy Evaluation Pattern Matching
- 24. Higher Order functions “Functionsas first class values” http://www.dreamstime.com/looking-up-to-the-sky-thumb4655038.jpg
- 25. Higher Order functions “Functionsthat can be passed as arguments” def square(x): return x * x def add(function, x): return function(x) + function(x) print add(square, 5)
- 26. Higher Order functions “Functionsthat can be returned as results” function addNumber(x) { return function(y) { return x + y } } var add4With = addNumber(4) var add5With = addNumber(5) add4with(8) add5with(8) 12 13
- 27. Higher Order functions “Functions that can be returned as results” function addNumber(x) { Lambda Functions return function(y) { return x + y } } var add4With = addNumber(4) var add5With = addNumber(5) add4with(8) add5with(8) 12 13
- 28. Higher Order functions “Functions that can be returned as results” function addNumber(x) { Lambda Functions return function(y) { return x + y } } var add4With = addNumber(4) var add5With = addNumber(5) add4with(8) Functions stored in add5with(8) data structures 12 13
- 29. Higher Order functions “Currying” let add x y = x + y val add : int -> int -> int > let add5 = add 5;; val add5 : (int -> int) > add5 4;; val it : int = 9 >
- 30. Referential Transparency Higher Orderfunctions Lazy Evaluation Pattern Matching
- 31. Lazy Evaluation “Arguments ina function call are evaluated at most once.” http://www.arngren.dk/image/Wallpaper/Comic/Calvin%20Hobbes/Sleeping1024.jpg
- 32. Lazy Evaluation “Ability toinvoke expressions only when its value is needed.” static void Main(string[] args) { var lazy = new Lazy<int>(() => { Console.WriteLine("calculating..."); return 6 * 7; }); Console.WriteLine(lazy.Value); Console.WriteLine(lazy.Value); }
- 33. Lazy Evaluation “Ability toinvoke expressions only when its value is needed.” static void Main(string[] args) { var lazy = new Lazy<int>(() => { Console.WriteLine("calculating..."); return 6 * 7; }); Console.WriteLine(lazy.Value); Console.WriteLine(lazy.Value); } calculating... 42 42
- 34. Lazy Evaluation “Memoization” function Lazy_Memoized(def) { var cache = []; return function(i) { return (i in cache) ? cache[i] : (cache[i] = def.call(arguments.callee, i)); }; } var factorial = new Lazy_Memoized(function(i) { return i <= 1 ? i : i * this(i - 1); }); factorial(6)
- 35. Lazy Evaluation “Ability to create infinite sequence in data structures” http://softwarezku.co.cc/wp-content/uploads/2010/09/Visual-Studio-2010-Logo.png
- 36. Referential Transparency Higher Orderfunctions Lazy Evaluation Pattern Matching
- 37. Pattern Matching “Writing several equations defining the same function” http://softwareandfinance.com/images/vcpp-trig1.jpg
- 38. Pattern Matching A typicalfunction definition f(x) = 1, when x = 0 = 3x + ex, when x > 0
- 39. Pattern Matching A typicalfunction definition fac :: Integer -> Integer fac 0 = 1 fac n | n > 0 = n * fac(n-1) let rec factorial = function | 0 -> 1 | n -> n * factorial(n - 1)
- 42. References • Concepts, Evolution and Application of Functional Programming Languages – Paul Hudak • http://msdn.microsoft.com/en-us/library/dd547125.aspx - Pattern Matching in F# • http://appden.com/javascript/lazy-list-comprehensions-in-javascript-a-lazy- evalution/ • http://images.google.com • http://en.wikipedia.org • http://www.haskell.org/haskellwiki/Haskell • http://homepages.inf.ed.ac.uk/wadler/