Tutorial by Examples: l

package { import flash.events.TimerEvent; import flash.utils.Timer; public class CountdownTimer extends Timer { public var time:Number = 0; public function CountdownTimer(time:Number = Number.NEGATIVE_INFINITY, delay:Number = 1000) { super(delay, repeatCount); ...

Using functions that take in and execute closures can be extremely useful for sending a block of code to be executed elsewhere. We can start by allowing our function to take in an optional closure that will (in this case) return Void. func closedFunc(block: (()->Void)? = nil) { print("...

Note: Everything below applies to the str.format method, as well as the format function. In the text below, the two are interchangeable. For every value which is passed to the format function, Python looks for a __format__ method for that argument. Your own custom class can therefore have th...

// RawRepresentable has an associatedType RawValue. // For this struct, we will make the compiler infer the type // by implementing the rawValue variable with a type of String // // Compiler infers RawValue = String without needing typealias // struct NotificationName: RawRepresentable { ...

A protocol may specify that only a class can implement it through using the class keyword in its inheritance list. This keyword must appear before any other inherited protocols in this list. protocol ClassOnlyProtocol: class, SomeOtherProtocol { // Protocol requirements } If a non-class typ...

Select the .xcdatamodeld file. You will notice you have no entities. You will have to create one yourself. At the bottom of Xcode you will notice a button that says "Add Entity" click it and you will have a new entity for you to work with on the project. In this step there are ...

With Gson, you can read JSON dataset and map them to a custom class MyClass. Since Gson is not serializable, each executor needs its own Gson object. Also, MyClass must be serializable in order to pass it between executors. Note that the file(s) that is offered as a json file is not a typical JSON...

We define the type of boolean expressions whose atoms are identified by strings as type expr = | Atom of string | Not of expr | And of expr * expr | Or of expr * expr and can evaluate these expressions using an oracle : string -> bool giving the values of the atoms we find as follows: le...

Pattern matching allows to deconstruct complex values and it is by no way limited to the “outer most” level of the representation of a value. To illustrate this, we implement the function transforming a boolean expression into a boolean expression where all negations are only on atoms, the so calle...

Pattern matching can be used to deconstruct records. We illustrate this with a record type representing locations in a text file, e.g. the source code of a program. type location = { filename : string; line: int; column: int; offset: int; } A value x of type location can be deconstr...

The List.fold_left and List.fold_right functions are higher-order functions that implement the outer logic of list aggregation. Aggregating a list, sometimes also referred to as reducing a list, means computing a value derived from the sequential inspection of all items in that list. The documenta...

// assume a Request and RequestQueue have already been initialized somewhere above public static final String TAG = "SomeTag"; // Set the tag on the request. request.setTag(TAG); // Add the request to the RequestQueue. mRequestQueue.add(request); // To cancel this specific re...

In Elm, reducing functions are called "folds", and there are two standard methods to "fold" values up: from the left, foldl, and from the right, foldr. > List.foldl (+) 0 [1,2,3] 6 : number The arguments to foldl and foldr are: reducing function: newValue -> accumul...

Woocommerce is a plugin for WordPress and can be installed like any other WordPress plugin. WooCommerce can only be installed on self hosted installations of WordPress, it cannot be installed onto a site hosted by the wordpress.com service. If you don't have WordPress installed for your website, fo...

A while loop will evaluate its condition, and if true, it will execute the code inside and start over. That is, as long as its condition evaluates to true, the while loop will execute over and over. This loop will execute 100 times, each time adding 1 to the variable num: int num = 0; while (nu...

A do while loop is the same as a while loop, except that it is guaranteed to execute at least one time. The following loop will execute 100 times. int i = 0; do { i++; } while (i < 100); A similar loop, but with a different condition, will execute 1 time. int i = 0; do { i++; ...

There are some ways to break or change a loop's flow. break; will exit the current loop, and will not execute any more lines within that loop. continue; will not execute any more code within the current iteration of the loop, but will remain in the loop. The following loop will execute 101 times ...

localStorage, sessionStorage are JavaScript Objects and you can treat them as such. Instead of using Storage Methods like .getItem(), .setItem(), etc… here's a simpler alternative: // Set localStorage.greet = "Hi!"; // Same as: window.localStorage.setItem("greet", "Hi!&qu...

References to class declarations are typed Class: var spriteClass:Class = Sprite; You can use variables typed Class to instantiate instances of that class: var sprite:Sprite = new spriteClass(); This can be useful for passing an argument of type Class to a function that might create and inst...

The C++ approach - new and delete In a language like C++, the application program is responsible for managing the memory used by dynamically allocated memory. When an object is created in the C++ heap using the new operator, there needs to be a corresponding use of the delete operator to dispose o...