Tutorial by Examples: ga

Properties can be added with categories using associated objects, a feature of the Objective-C runtime. Note that the property declaration of retain, nonatomic matches the last argument to objc_setAssociatedObject. See Attach object to another existing object for explanations. #import <objc/run...

Extension methods are useful to extend the behaviour of libraries we don't own. They are used similar to instance methods thanks to the compiler's syntactic sugar: Sub Main() Dim stringBuilder = new StringBuilder() 'Extension called directly on the object. stringBuilder.AppendIf(t...

Naming Convention Notifications are identified by global NSString objects whose names are composed in this way: Name of associated class + Did | Will + UniquePartOfName + Notification For example: NSApplicationDidBecomeActiveNotification NSWindowDidMiniaturizeNotification NSTextViewDidChange...

Swift NSNotificationCenter.defaultCenter().postNotificationName("TestNotification", object: self) Objective-C [[NSNotificationCenter defaultCenter] postNotificationName:@"TestNotification" object:nil];

Swift let userInfo: [String: AnyObject] = ["someKey": myObject] NSNotificationCenter.defaultCenter().postNotificationName("TestNotification", object: self, userInfo: userInfo) Objective-C NSDictionary *userInfo = [NSDictionary dictionaryWithObject:myObject forKey:@"som...

Swift func testNotification(notification: NSNotification) { let userInfo = notification.userInfo let myObject: MyObject = userInfo["someKey"] } Objective-C - (void)testNotification:(NSNotification *)notification { NSDictionary *userInfo = notification.userInfo; My...

Ember CLI allows you to use one of two options to generate a new app: Create a folder and run ember init (generates application structure and sets up git and makes your first commit) Run ember new <app name> (creates a folder with the specified name, steps into it and runs ember init) O...

Maps are the Elixir key-value (also called dictionary or hash in other languages) type. You create a map using the %w{} syntax: %{} // creates an empty map %{:a => 1, :b => 2} // creates a non-empty map Keys and values can use be any type: %{"a" => 1, "b" => 2} ...

This example demonstrates that HTTP is a text-based Internet communications protocol, and shows a basic HTTP request and the corresponding HTTP response. You can use Telnet to manually send a minimal HTTP request from the command line, as follows. Start a Telnet session to the web server www.e...

0.18.0 Prior to 0.18.0 you can create ranges like this: > range = [1..5] [1,2,3,4,5] : List number > > negative = [-5..3] [-5,-4,-3,-2,-1,0,1,2,3] : List number 0.18.0 In 0.18.0 The [1..5] syntax has been removed. > range = List.range 1 5 [1,2,3,4,5] : List number > &g...

> listOfNumbers = [1,4,99] [1,4,99] : List number > > listOfStrings = ["Hello","World"] ["Hello","World"] : List String > > emptyList = [] -- can be anything, we don't know yet [] : List a > Under the hood, List (linked list) is ...

List.filter : (a -> Bool) -> List a -> List a is a higher-order function which takes a one-parameter function from any value to a boolean, and applies that function to every element of a given list, keeping only those elements for which the function returns True on. The function that List.f...

def minus(left: Int, right: Int) = left - right val numberMinus5 = minus(_: Int, 5) val fiveMinusNumber = minus(5, _: Int) numberMinus5(7) // 2 fiveMinusNumber(7) // -2

Use .split to go from strings to an array of the split substrings: var s = "one, two, three, four, five" s.split(", "); // ["one", "two", "three", "four", "five"] Use the array method .join to go back to a string: s.split(&...

To detect whether a parameter is a primitive string, use typeof: var aString = "my string"; var anInt = 5; var anObj = {}; typeof aString === "string"; // true typeof anInt === "string"; // false typeof anObj === "string"; // false If you ev...

This demonstrates how to print each element of a Map val map = Map(1 -> "a", 2 -> "b") for (number <- map) println(number) // prints (1,a), (2,b) for ((key, value) <- map) println(value) // prints a, b This demonstrates how to print each element of a list val l...

using System.Runtime.InteropServices; class PInvokeExample { [DllImport("user32.dll", CharSet = CharSet.Auto)] public static extern uint MessageBox(IntPtr hWnd, String text, String caption, int options); public static void test() { MessageBox(IntPtr.Zero,...

Arrays of simple type [DllImport("Example.dll")] static extern void SetArray( [MarshalAs(UnmanagedType.LPArray, SizeConst = 128)] byte[] data); Arrays of string [DllImport("Example.dll")] static extern void SetStrArray(string[] textLines);

A Map is a basic mapping of keys to values. Maps are different from objects in that their keys can be anything (primitive values as well as objects), not just strings and symbols. Iteration over Maps is also always done in the order the items were inserted into the Map, whereas the order is undefine...

Grand Central Dispatch works on the concept of "Dispatch Queues". A dispatch queue executes tasks you designate in the order which they are passed. There are three types of dispatch queues: Serial Dispatch Queues (aka private dispatch queues) execute one task at a time, in order. They a...