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F# allows functions to be added as "members" to types when they are defined (for example, Record Types). However F# also allows new instance members to be added to existing types - even ones declared elsewhere and in other .net languages. The following example adds a new instance method D...

F# allow existing types to be extended with new static functions. type System.String with static member EqualsCaseInsensitive (a, b) = String.Equals(a, b, StringComparison.OrdinalIgnoreCase) This new function can be invoked like this: let x = String.EqualsCaseInsensitive("abc", &...

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...

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil]; With an Identifier: Give the scene a Storyboard ID within the identity inspector of the storyboard. Instantiate in code: UIViewController *controller = [storyboard instantiateViewControllerWithIdentifi...

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

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

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" ...

Download and install Xamarin Studio Community. Open Xamarin Studio. Click File → New → Solution. Click .NET → Console Project and choose C#. Click Next to proceed. Enter the Project Name and Browse... for a Location to Save and then click Create. The newly created project w...

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 ...

Creating the JFrame Creating a window is easy. You just have to create a JFrame. JFrame frame = new JFrame(); Titling the Window You may wish to give your window a title. You can so do by passing a string when creating the JFrame, or by calling frame.setTitle(String title). JFrame frame = new...

A component is some sort of user interface element, such as a button or a text field. Creating a Component Creating components is near identical to creating a window. Instead of creating a JFrame however, you create that component. For example, to create a JButton, you do the following. JButton b...

Components have various parameters that can be set for them. They vary from component to component, so a good way to see what parameters can be set for components is to start typing componentName.set, and let your IDE's autocomplete (If you use an IDE) suggest methods. The default shortcut in many I...

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...

Having a button there is all well and good, but what's the point if clicking it does nothing? ActionListeners are used to tell your button, or other component to do something when it is activated. Adding ActionListeners is done as such. buttonA.addActionListener(new ActionListener() { @Overri...

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) ->...