Tutorial by Examples: l

In many environments, you have access to a global console object that contains some basic methods for communicating with standard output devices. Most commonly, this will be the browser's JavaScript console (see Chrome, Firefox, Safari, and Edge for more information). // At its simplest, you can 'l...

Hstore columns can be useful to store settings. They are available in PostgreSQL databases after you enabled the extension. class CreatePages < ActiveRecord::Migration[5.0] def change create_table :pages do |t| enable_extension 'hstore' unless extension_enabled?('hstore') t...

The ng-click directive attaches a click event to a DOM element. The ng-click directive allows you to specify custom behavior when an element of DOM is clicked. It is useful when you want to attach click events on buttons and handle them at your controller. This directive accepts an expression wit...

Vagrantfile Vagrant.configure("2") do |config| config.vm.box = "ubuntu/trusty64" config.vm.provision "ansible" do |ansible| ansible.playbook = "vagrant-playbook.yml" end end vagrant-playbook.yml --- - hosts: default tasks: - name: ...

vagrant up By default the box will be provisioned.

vagrant up --no-provision

Modules can be used to add new functions to existing Modules and Types. namespace FSharp.Collections module List = let pair item1 item2 = [ item1; item2 ] The new function can then be called as if it was an original member of List. open FSharp.Collections module Testing = le...

from struct import pack print(pack('I3c', 123, b'a', b'b', b'c')) # b'{\x00\x00\x00abc'

To use a FloatingActionButton just add the dependency in the build.gradle file as described in the remarks section. Then add to the layout: <android.support.design.widget.FloatingActionButton android:id="@+id/fab" android:layout_width="wrap_content" ...

HTTP requests are made through the WSClient class, which you can use as an injected parameter into your own classes. import javax.inject.Inject import play.api.libs.ws.WSClient import scala.concurrent.{ExecutionContext, Future} class MyClass @Inject() ( wsClient: WSClient )(implicit ...

Layouts are used whenever you want your components to not just be displayed next to each other. The GridBagLayout is a useful one, as it divides your window into rows and columns, and you decide which row and column to put components into, as well as how many rows and colums big the component is. L...

The following examples show 3 main methods for installing Erlang/OTP on FreeBSD. Method 1 - Pre-built Binary Package Use pkg to install the pre-built binary package: $ pkg install erlang Test your new installation: $ erl Erlang/OTP 18 [erts-7.3.1] [source] [64-bit] [smp:2:2] [async-threads:1...

You can build a JSON object tree (a JsValue) manually import play.api.libs.json._ val json = JsObject(Map( "name" -> JsString("Jsony McJsonface"), "age" -> JsNumber(18), "hobbies" -> JsArray(Seq( JsString("Fishing"), ...

Catamorphisms, or folds, model primitive recursion. cata tears down a fixpoint layer by layer, using an algebra function (or folding function) to process each layer. cata requires a Functor instance for the template type f. cata :: Functor f => (f a -> a) -> Fix f -> a cata f = f . fma...

Anamorphisms, or unfolds, model primitive corecursion. ana builds up a fixpoint layer by layer, using a coalgebra function (or unfolding function) to produce each new layer. ana requires a Functor instance for the template type f. ana :: Functor f => (a -> f a) -> a -> Fix f ana f = Fi...

It's common to structure a program as building up a data structure and then collapsing it to a single value. This is called a hylomorphism or refold. It's possible to elide the intermediate structure altogether for improved efficiency. hylo :: Functor f => (a -> f a) -> (f b -> b) ->...

If you already have sbt installed I find it easier to create a minimal Play project without activator. Here's how. # create a new folder mkdir myNewProject # launch sbt sbt When previous steps are completed, edit build.sbt and add the following lines name := """myProjectName&q...

CREATE TABLE table_name ( id INT NOT NULL AUTO_INCREMENT, json_col JSON, PRIMARY KEY(id) );

INSERT INTO table_name (json_col) VALUES ('{"City": "Galle", "Description": "Best damn city in the world"}'); That's simple as it can get but note that because JSON dictionary keys have to be surrounded by double quotes the entire thing should b...

C++11 Basic example: template<typename T> using pointer = T*; This definition makes pointer<T> an alias of T*. For example: pointer<int> p = new int; // equivalent to: int* p = new int; Alias templates cannot be specialized. However, that functionality can be obtained indi...