Hello World!

hello_world.php

<?php
/**
 * @package Hello_World
 * @version 0.1
 *
 * Plugin Name: Hello World!
 * Plugin URI: https://gist.github.com/rnagle/d561bd58504a644e9657
 * Description: Just a simple WordPress plugin that prints "Hello world!" in the top corner of the WordPress dashboard.
 * Author: Ryan Nagle
 * Version: 0.1
 **/

function hello_world() {
  return "Hello world!";
}

function hello_world_markup() {
	echo "<p id='hello-world'>" . hello_world() . "</p>";
}
add_action('admin_notices', 'hello_world_markup');

function hello_world_css() {
	$x = is_rtl() ? 'left' : 'right';

	echo "
	<style type='text/css'>
	#hello-world {
		float: $x;
		padding-$x: 15px;
		padding-top: 5px;
		margin: 0;
		font-size: 11px;
	}
	</style>
	";
}
add_action('admin_head', 'hello_world_css');