Tutorial by Examples: in

Redirecting STDERR

2 is STDERR. $ echo_to_stderr 2>/dev/null # echos nothing Definitions: echo_to_stderr is a command that writes "stderr" to STDERR echo_to_stderr () { echo stderr >&2 } $ echo_to_stderr stderr

Bash • Redirection

The type of the literal Without any extensions, the type of a string literal – i.e., something between double quotes – is just a string, aka list of characters: Prelude> :t "foo" "foo" :: [Char] However, when the OverloadedStrings extension is enabled, string literals be...

Haskell Language • Overloaded Literals

Registering New Elements

Defines an <initially-hidden> custom element which hides its contents until a specified number of seconds have elapsed. const InitiallyHiddenElement = document.registerElement('initially-hidden', class extends HTMLElement { createdCallback() { this.revealTimeoutId = null; } at...

JavaScript • Custom Elements

Extending Native Elements

It's possible to extent native elements, but their descendants don't get to have their own tag names. Instead, the is attribute is used to specify which subclass an element is supposed to use. For example, here's an extension of the <img> element which logs a message to the console when it's l...

JavaScript • Custom Elements

Interaction with Promises

6 Exceptions are to synchronous code what rejections are to promise-based asynchronous code. If an exception is thrown in a promise handler, its error will be automatically caught and used to reject the promise instead. Promise.resolve(5) .then(result => { throw new Error("I ...

JavaScript • Error Handling

Compiling with GCC

Assuming a single source file named main.cpp, the command to compile and link an non-optimized executable is as follows (Compiling without optimization is useful for initial development and debugging, although -Og is officially recommended for newer GCC versions). g++ -o app -Wall main.cpp -O0 T...

C++ • Compiling and Building

Get Started in Xamarin Studio

Browse to File > New > Solution to bring you up the new project dialog Select Single View App and press Next Configure your app by setting your app name and organization ID, and press Next: Set your Project name and Solution name, or leave as the default name. Click Create to create...

Xamarin.iOS • Getting started with Xamarin.iOS

Float an Image Within Text

The most basic use of a float is having text wrap around an image. The below code will produce two paragraphs and an image, with the second paragraph flowing around the image. Notice that it is always content after the floated element that flows around the floated element. HTML: <p>Lorem ips...

CSS • Floats

Event Bubbling and Capturing

Events fired on DOM elements don't just affect the element they're targeting. Any of the target's ancestors in the DOM may also have a chance to react to the event. Consider the following document: <!DOCTYPE html> <html> <head> <meta charset="utf-8" /> </hea...

DOM • Events

Checking arithmetic with assert

a = 1 - Math.abs(1 - a % 2); // This will throw an error if my arithmetic above is wrong. assert a >= 0 && a <= 1 : "Calculated value of " + a + " is outside of expected bounds"; return a;

Java Language • Asserting

Downloading a file via curl

This downloads a file from the Dropbox API at the remote path /Homework/math/Prime_Numbers.txt to the local path Prime_Numbers.txt in the current folder: curl -X POST https://content.dropboxapi.com/2/files/download \ --header "Authorization: Bearer <ACCESS_TOKEN>" \ --head...