Merge remote-tracking branch 'upstream/master'

2025-01-15 21:55:59 +00:00 · 2015-03-16 14:25:46 -06:00 · 2015-03-16 14:25:46 -06:00 · 366fe47ffa
commit 366fe47ffa
parent 752279248e a6ea67e733
4 changed files with 123 additions and 76 deletions
--- a/c++.html.markdown
+++ b/c++.html.markdown
@ -30,10 +30,10 @@ one of the most widely-used programming languages.

 // C++ is _almost_ a superset of C and shares its basic syntax for
 // variable declarations, primitive types, and functions.
-// However, C++ varies in some of the following ways:

-// A main() function in C++ should return an int,
-// though void main() is accepted by most compilers (gcc, clang, etc.)
+// Just like in C, your program's entry point is a function called
+// main with an integer return type,
+// though void main() is also accepted by most compilers (gcc, clang, etc.)
 // This value serves as the program's exit status.
 // See http://en.wikipedia.org/wiki/Exit_status for more information.
 int main(int argc, char** argv)
@ -51,6 +51,8 @@ int main(int argc, char** argv)
    return 0;
 }

+// However, C++ varies in some of the following ways:
+
 // In C++, character literals are one byte.
 sizeof('c') == 1

--- a/java.html.markdown
+++ b/java.html.markdown
@ -103,15 +103,15 @@ public class LearnJava {
        // Arrays
        //The array size must be decided upon instantiation
        //The following formats work for declaring an array
-        //<datatype> [] <var name> = new <datatype>[<array size>];
+        //<datatype>[] <var name> = new <datatype>[<array size>];
        //<datatype> <var name>[] = new <datatype>[<array size>];
-        int [] intArray = new int[10];
-        String [] stringArray = new String[1];
-        boolean boolArray [] = new boolean[100];
+        int[] intArray = new int[10];
+        String[] stringArray = new String[1];
+        boolean boolArray[] = new boolean[100];

        // Another way to declare & initialize an array
-        int [] y = {9000, 1000, 1337};
-        String names [] = {"Bob", "John", "Fred", "Juan Pedro"};
+        int[] y = {9000, 1000, 1337};
+        String names[] = {"Bob", "John", "Fred", "Juan Pedro"};
        boolean bools[] = new boolean[] {true, false, false};

        // Indexing an array - Accessing an element
--- a/racket.html.markdown
+++ b/racket.html.markdown
@ -7,6 +7,7 @@ contributors:
  - ["Eli Barzilay", "https://github.com/elibarzilay"]
  - ["Gustavo Schmidt", "https://github.com/gustavoschmidt"]
  - ["Duong H. Nguyen", "https://github.com/cmpitg"]
+  - ["Keyan Zhang", "https://github.com/keyanzhang"]
 ---

 Racket is a general purpose, multi-paradigm programming language in the Lisp/Scheme family.
@ -282,16 +283,49 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))  <-- no `d'

 ;; for numbers use `='
 (= 3 3.0) ; => #t
-(= 2 1) ; => #f
+(= 2 1)   ; => #f
+
+;; `eq?' returns #t if 2 arguments refer to the same object (in memory), 
+;; #f otherwise.
+;; In other words, it's a simple pointer comparison.
+(eq? '() '()) ; => #t, since there exists only one empty list in memory
+(let ([x '()] [y '()])
+  (eq? x y))  ; => #t, same as above

-;; for object identity use `eq?'
-(eq? 3 3) ; => #t
-(eq? 3 3.0) ; => #f
 (eq? (list 3) (list 3)) ; => #f
+(let ([x (list 3)] [y (list 3)])
+  (eq? x y))            ; => #f — not the same list in memory!

-;; for collections use `equal?'
-(equal? (list 'a 'b) (list 'a 'b)) ; => #t
-(equal? (list 'a 'b) (list 'b 'a)) ; => #f
+(let* ([x (list 3)] [y x])
+  (eq? x y)) ; => #t, since x and y now point to the same stuff
+
+(eq? 'yes 'yes) ; => #t
+(eq? 'yes 'no)  ; => #f
+
+(eq? 3 3)   ; => #t — be careful here
+            ; It’s better to use `=' for number comparisons.
+(eq? 3 3.0) ; => #f
+
+(eq? (expt 2 100) (expt 2 100))               ; => #f
+(eq? (integer->char 955) (integer->char 955)) ; => #f
+
+(eq? (string-append "foo" "bar") (string-append "foo" "bar")) ; => #f
+
+;; `eqv?' supports the comparison of number and character datatypes.
+;; for other datatypes, `eqv?' and `eq?' return the same result.
+(eqv? 3 3.0)                                   ; => #f
+(eqv? (expt 2 100) (expt 2 100))               ; => #t
+(eqv? (integer->char 955) (integer->char 955)) ; => #t
+
+(eqv? (string-append "foo" "bar") (string-append "foo" "bar"))   ; => #f
+
+;; `equal?' supports the comparison of the following datatypes:
+;; strings, byte strings, pairs, mutable pairs, vectors, boxes, 
+;; hash tables, and inspectable structures.
+;; for other datatypes, `equal?' and `eqv?' return the same result.
+(equal? 3 3.0)                                                   ; => #f
+(equal? (string-append "foo" "bar") (string-append "foo" "bar")) ; => #t
+(equal? (list 3) (list 3))                                       ; => #t

 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; 5. Control Flow
--- a/typescript.html.markdown
+++ b/typescript.html.markdown
@ -14,100 +14,111 @@ This article will focus only on TypeScript extra syntax, as oposed to [JavaScrip
 To test TypeScript's compiler, head to the [Playground] (http://www.typescriptlang.org/Playground) where you will be able to type code, have auto completion and directly see the emitted JavaScript.

 ```js
-//There are 3 basic types in TypeScript
+// There are 3 basic types in TypeScript
 var isDone: boolean = false;
 var lines: number = 42;
 var name: string = "Anders";

-//..When it's impossible to know, there is the "Any" type
+// When it's impossible to know, there is the "Any" type
 var notSure: any = 4;
 notSure = "maybe a string instead";
 notSure = false; // okay, definitely a boolean

-//For collections, there are typed arrays and generic arrays
+// For collections, there are typed arrays and generic arrays
 var list: number[] = [1, 2, 3];
-//Alternatively, using the generic array type
+// Alternatively, using the generic array type
 var list: Array<number> = [1, 2, 3];

-//For enumerations:
+// For enumerations:
 enum Color {Red, Green, Blue};
 var c: Color = Color.Green;

-//Lastly, "void" is used in the special case of a function not returning anything
+// Lastly, "void" is used in the special case of a function returning nothing
 function bigHorribleAlert(): void {
  alert("I'm a little annoying box!");
 }

-//Functions are first class citizens, support the lambda "fat arrow" syntax and use type inference
-//All examples are equivalent, the same signature will be infered by the compiler, and same JavaScript will be emitted
-var f1 = function(i: number) : number { return i * i; }
-var f2 = function(i: number) { return i * i; } //Return type infered
-var f3 = (i : number) : number => { return i * i; }
-var f4 = (i: number) => { return i * i; } //Return type infered
-var f5 = (i: number) =>  i * i; //Return type infered, one-liner means no return keyword needed
+// Functions are first class citizens, support the lambda "fat arrow" syntax and
+// use type inference

-//Interfaces are structural, anything that has the properties is compliant with the interface
+// The following are equivalent, the same signature will be infered by the
+// compiler, and same JavaScript will be emitted
+var f1 = function(i: number): number { return i * i; }
+// Return type inferred
+var f2 = function(i: number) { return i * i; }
+var f3 = (i: number): number => { return i * i; }
+// Return type inferred
+var f4 = (i: number) => { return i * i; }
+// Return type inferred, one-liner means no return keyword needed
+var f5 = (i: number) =>  i * i;
+
+// Interfaces are structural, anything that has the properties is compliant with
+// the interface
 interface Person {
  name: string;
-  //Optional properties, marked with a "?"
+  // Optional properties, marked with a "?"
  age?: number;
-  //And of course functions
+  // And of course functions
  move(): void;
 }

-//..Object that implements the "Person" interface
-var p : Person = { name: "Bobby", move : () => {} }; //Can be treated as a Person since it has the name and age properties
-//..Objects that have the optional property:
-var validPerson : Person = { name: "Bobby", age: 42, move: () => {} };
-var invalidPerson : Person = { name: "Bobby", age: true }; //Is not a person because age is not a number
+// Object that implements the "Person" interface
+// Can be treated as a Person since it has the name and move properties
+var p: Person = { name: "Bobby", move: () => {} };
+// Objects that have the optional property:
+var validPerson: Person = { name: "Bobby", age: 42, move: () => {} };
+// Is not a person because age is not a number
+var invalidPerson: Person = { name: "Bobby", age: true };

-//..Interfaces can also describe a function type
+// Interfaces can also describe a function type
 interface SearchFunc {
  (source: string, subString: string): boolean;
 }
-//..Only the parameters' types are important, names are not important.
+// Only the parameters' types are important, names are not important.
 var mySearch: SearchFunc;
 mySearch = function(src: string, sub: string) {
  return src.search(sub) != -1;
 }

-//Classes - members are public by default
+// Classes - members are public by default
 class Point {
-  //Properties
-	x: number;
+  // Properties
+    x: number;

-	//Constructor - the public/private keywords in this context will generate the boiler plate code
-	// for the property and the initialization in the constructor.
-	// In this example, "y" will be defined just like "x" is, but with less code
-	//Default values are also supported
-	constructor(x: number, public y: number = 0) {
-		this.x = x;
-	}
+    // Constructor - the public/private keywords in this context will generate
+    // the boiler plate code for the property and the initialization in the
+    // constructor.
+    // In this example, "y" will be defined just like "x" is, but with less code
+    // Default values are also supported

-	//Functions
-	dist() { return Math.sqrt(this.x * this.x + this.y * this.y); }
+    constructor(x: number, public y: number = 0) {
+        this.x = x;
+    }

-	//Static members
-	static origin = new Point(0, 0);
+    // Functions
+    dist() { return Math.sqrt(this.x * this.x + this.y * this.y); }
+
+    // Static members
+    static origin = new Point(0, 0);
 }

 var p1 = new Point(10 ,20);
 var p2 = new Point(25); //y will be 0

-//Inheritance
+// Inheritance
 class Point3D extends Point {
-	constructor(x: number, y: number, public z: number = 0) {
-		super(x, y); //Explicit call to the super class constructor is mandatory
-	}
+    constructor(x: number, y: number, public z: number = 0) {
+        super(x, y); // Explicit call to the super class constructor is mandatory
+    }

-	//Overwrite
-	dist() {
-		var d = super.dist();
-		return Math.sqrt(d * d + this.z * this.z);
-	}
+    // Overwrite
+    dist() {
+        var d = super.dist();
+        return Math.sqrt(d * d + this.z * this.z);
+    }
 }

-//Modules, "." can be used as separator for sub modules
+// Modules, "." can be used as separator for sub modules
 module Geometry {
  export class Square {
    constructor(public sideLength: number = 0) {
@ -120,32 +131,32 @@ module Geometry {

 var s1 = new Geometry.Square(5);

-//..Local alias for referencing a module
+// Local alias for referencing a module
 import G = Geometry;

 var s2 = new G.Square(10);

-//Generics
-//..Classes
+// Generics
+// Classes
 class Tuple<T1, T2> {
    constructor(public item1: T1, public item2: T2) {
    }
 }

-//..Interfaces
+// Interfaces
 interface Pair<T> {
-	item1: T;
-	item2: T;
+    item1: T;
+    item2: T;
 }

-//..And functions
+// And functions
 var pairToTuple = function<T>(p: Pair<T>) {
-	return new Tuple(p.item1, p.item2);
+    return new Tuple(p.item1, p.item2);
 };

 var tuple = pairToTuple({ item1:"hello", item2:"world"});

-//Including references to a definition file:
+// Including references to a definition file:
 /// <reference path="jquery.d.ts" />

 ```