Tutorial by Examples: io

To make a Haskell program executable you must provide a file with a main function of type IO () main :: IO () main = putStrLn "Hello world!" When Haskell is compiled it examines the IO data here and turns it into a executable. When we run this program it will print Hello world!. If y...

Output some information about a known remote: origin git remote show origin Print just the remote's URL: git config --get remote.origin.url With 2.7+, it is also possible to do, which is arguably better than the above one that uses the config command. git remote get-url origin

Laravel allows access to a variety of classes called Services. Some services are available out of the box, but you can create them by yourself. A service can be used in multiple files of the application, like controllers. Let's imagine a Service OurService implementing a getNumber() method returnin...

In a Service Provider register method we can bind an interface to an implementation: public function register() { App::bind( UserRepositoryInterface::class, EloquentUserRepository::class ); } From now on, everytime the app will need an instance of UserRepositoryInterface, Larave...

The Service Container is the main Application object. It can be used as a Dependency Injection Container, and a Registry for the application by defining bindings in the Service Providers Service Providers are classes where we define the way our service classes will be created through the applicatio...

chrome.runtime.getManifest() returns the extension's manifest in a form of a parsed object. This method works both on content scripts and all extension pages, it requires no permissions, Example, obtaining the extension's version string: var version = chrome.runtime.getManifest().version;

This method will work on modern versions of Arch, CentOS, CoreOS, Debian, Fedora, Mageia, openSUSE, Red Hat Enterprise Linux, SUSE Linux Enterprise Server, Ubuntu, and others. This wide applicability makes it an ideal as a first approach, with fallback to other methods if you need to also identify o...

To cancel a call to requestAnimationFrame, you need the id it returned from when it was last called. This is the parameter you use for cancelAnimationFrame. The following example starts some hypothetical animation then pauses it after one second. // stores the id returned from each call to reques...

In contrast of a full template specialization partial template specialization allows to introduce template with some of the arguments of existing template fixed. Partial template specialization is only available for template class/structs: // Common case: template<typename T, typename U> st...

A commonly used CSS/Javascript library is Bootstrap. To install it into your Aurelia CLI driven application first you need to install it using Npm. npm install bootstrap --save Because Bootstrap has a hard dependency on jQuery, we need to make sure we also have jQuery installed: npm install jqu...

A bi-directional value converter utilizes two methods in your Value Converter class: toView and fromView these methods are aptly named to signify which direction the data is flowing. In our example we will be creating a prepend Value Converter which will make sure that an amount entered in our app ...

Similar to hsl() notation, but with an added alpha (opacity) value. hsla(240, 100%, 50%, 0) /* transparent */ hsla(240, 100%, 50%, 0.5) /* half-translucent blue */ hsla(240, 100%, 50%, 1) /* fully opaque blue */ Syntax hsla(<hue>, <saturation>%, <lightness>%, <a...

Stateless components are getting their philosophy from functional programming. Which implies that: A function returns all time the same thing exactly on what is given to it. For example: const statelessSum = (a, b) => a + b; let a = 0; const statefulSum = () => a++; As you can see fro...

Recursion occurs when a function call causes that same function to be called again before the original function call terminates. For example, consider the well-known mathematical expression x! (i.e. the factorial operation). The factorial operation is defined for all nonnegative integers as follows:...

updateState by key can be used to create a stateful DStream based on upcoming data. It requires a function: object UpdateStateFunctions { def updateState(current: Seq[Double], previous: Option[StatCounter]) = { previous.map(s => s.merge(current)).orElse(Some(StatCounter(current))) } ...

mapWithState, similarly to updateState, can be used to create a stateful DStream based on upcoming data. It requires StateSpec: import org.apache.spark.streaming._ object StatefulStats { val state = StateSpec.function( (key: String, current: Option[Double], state: State[StatCounter]) =&g...

yii migrate/create <name> The required name argument gives a brief description about the new migration. For example, if the migration is about creating a new table named news, you may use the name create_news_table and run the following command yii migrate/create create_news_table

<?php use yii\db\Migration; class m150101_185401_create_news_table extends Migration { public function up() { } public function down() { echo "m101129_185401_create_news_table cannot be reverted.\n"; return false; } /* // Use safeUp/safeDown to run migra...

yii migrate/down # revert the most recently applied migration yii migrate/down 3 # revert the most 3 recently applied migrations

public function safeUp() { $this->createTable('news', [ 'id' => $this->primaryKey(), 'title' => $this->string()->notNull(), 'content' => $this->text(), ]); $this->insert('news', [ 'title' => 'test 1', 'conte...