Some code we're using at XWP to make plugins easier and cleaner to write.

example.php

<?php

require_once __DIR__ . '/pluginception.php'

class ShoutPlugin {
	use Pluginception;
	
	function __construct() {
		/*
		 * This method comes from the Pluginception trait, 
		 * and will parse out @action/@filter tags from this 
		 * object's methods' PhpDoc blocks, and then call
		 * add_action() and add_filter(). Note that the 
		 * arg count is not passed, as the PHP_MAX_INT is
		 * used instead.
		 */
		$this->add_hooks_from_object_method_docblocks();
	}
	
	/**
	 * Make all post titles ¡SHOUT!
	 * 
	 * @filter the_title
	 * 
	 * @param string $title
	 * @return string
	 */
	function shoutify_title( $title ) {
		$title = '¡' . strtoupper( $title ) . '!';
		return $title;
	}
	
	/**
	 * This will get added to the very bottom (priority 100) of the footer.
	 * 
	 * @action wp_footer, 100
	 */
	function show_props() {
		?>
		<p>Props Shady Sharaf for idea to use Reflection API to parse out the
		<code>@filter</code>/<code>@action</code> tags from method PhpDoc.</p>
		<?php
	}
}

$shout_plugin = new ShoutPlugin();

pluginception.php

<?php

/**
 * Add improved add_filter/add_action methods to any class, and support for declaring
 * filter/action callbacks via tags in PhpDoc comments. Props Shady Sharaf (@shadyvb)
 * for this application of the Reflection API.
 */
trait Pluginception {

	/**
	 * @var array
	 */
	protected $added_hooks = array();

	/**
	 *
	 */
	function __destruct() {
		$this->remove_all_hooks();
	}

	/**
	 * @param $name
	 * @param $callback
	 * @param array $args
	 *
	 * @return mixed
	 */
	function add_filter( $name, $callback, $args = array( 'priority' => 10, 'arg_count' => PHP_INT_MAX ) ) {
		return $this->_add_hook( 'filter', $name, $callback, $args );
	}

	/**
	 * @param $name
	 * @param $callback
	 * @param array $args
	 *
	 * @return mixed
	 */
	function add_action( $name, $callback, $args = array( 'priority' => 10, 'arg_count' => PHP_INT_MAX ) ) {
		return $this->_add_hook( 'action', $name, $callback, $args );
	}

	/**
	 * @param $type
	 * @param $name
	 * @param $callback
	 * @param array $args
	 *
	 * @return mixed
	 */
	protected function _add_hook( $type, $name, $callback, $args = array() ) {
		$priority = isset( $args['priority'] ) ? $args['priority'] : 10;
		$arg_count = isset( $args['arg_count'] ) ? $args['arg_count'] : PHP_INT_MAX;
		$fn = sprintf( '\add_%s', $type );
		$retval = \call_user_func( $fn, $name, $callback, $priority, $arg_count );
		$this->added_hooks[] = compact( 'type', 'name', 'callback', 'priority' );
		return $retval;
	}

	/**
	 * Add actions/filters from the methods of this class based on doc blocks
	 */
	function add_hooks_from_object_method_docblocks() {

		$reflector = new \ReflectionObject( $this );
		foreach ( $reflector->getMethods() as $method ) {
			$doc = $method->getDocComment();
			$arg_count = $method->getNumberOfParameters();
			if ( preg_match_all( '#\* @(?P<type>filter|action)\s+(?P<name>\w+)(?:,\s+(?P<priority>\d+))?#', $doc, $matches, PREG_SET_ORDER ) ) {
				foreach ( $matches as $match ) {
					$type = $match['type'];
					$name = $match['name'];
					$priority = is_null( $match['priority'] ) ? 10 : intval( $match['priority'] );
					$callback = array( $this, $method->getName() );
					call_user_func( array( $this, "add_{$type}" ), $name, $callback, $priority, $arg_count );
				}
			}
		}
	}

	/**
	 *
	 */
	function remove_all_hooks() {
		foreach ( $this->added_hooks as $added_hook ) {
			$fn = sprintf( 'remove_%s', $added_hook['type'] );
			call_user_func( $fn, $added_hook['name'], $added_hook['callback'], $added_hook['priority'] );
		}
	}
}