bootstrap.php

<?php
/*
Plugin Name: WordPress Plugin Skeleton
Plugin URI: https://github.com/iandunn/WordPress-Plugin-Skeleton
Description: The skeleton for an object-oriented/MVC WordPress plugin
Version: 0.4a
Author: Ian Dunn
Author URI: http://iandunn.name
*/

/* 
 * This plugin was built on top of WordPress-Plugin-Skeleton by Ian Dunn.
 * See https://github.com/iandunn/WordPress-Plugin-Skeleton for details.
 */


if( $_SERVER[ 'SCRIPT_FILENAME' ] == __FILE__ )
	die( 'Access denied.' );

define( 'WPPS_NAME',					'WordPress Plugin Skeleton' );
define( 'WPPS_REQUIRED_PHP_VERSION',	'5.3' );	// because of get_called_class()
define( 'WPPS_REQUIRED_WP_VERSION',		'3.1' );	// because of esc_textarea()

/**
 * Checks if the system requirements are met
 * @author Ian Dunn <ian@iandunn.name>
 * @return bool True if system requirements are met, false if not
 */
function wpps_requirementsMet()
{
	global $wp_version;
	//require_once( ABSPATH .'/wp-admin/includes/plugin.php' );		// to get is_plugin_active() early
	
	if( version_compare( PHP_VERSION, WPPS_REQUIRED_PHP_VERSION, '<' ) )
		return false;
	
	if( version_compare( $wp_version, WPPS_REQUIRED_WP_VERSION, '<' ) )
		return false;

	//if( !is_plugin_active( 'plugin-directory/plugin-file.php' ) )
		//return false;
	
	return true;
}

/**
 * Prints an error that the system requirements weren't met.
 * @author Ian Dunn <ian@iandunn.name>
 */
function wpps_requirementsError()
{
	global $wp_version;
	$class = 'error';
	
	ob_start();
	require_once( dirname( __FILE__ ) . '/views/requirements-error.php' );
	$message = ob_get_contents();
	ob_end_clean();
	
	require( dirname( __FILE__ ) . '/includes/IDAdminNotices/v-admin-notice.php' );
}

// Check requirements and load main class
// The main program needs to be in a separate file that only gets loaded if the plugin requirements are met. Otherwise older PHP installations could crash when trying to parse it.
if( wpps_requirementsMet() )
{
	require_once( dirname( __FILE__ ) . '/classes/wpps-module.php' );
	require_once( dirname( __FILE__ ) . '/classes/wordpress-plugin-skeleton.php' );

	if( class_exists( 'WordPressPluginSkeleton' ) )
	{
		$wpps = WordPressPluginSkeleton::getInstance();
		register_activation_hook( __FILE__,		array( $wpps, 'activate' ) );
		register_deactivation_hook( __FILE__,	array( $wpps, 'deactivate' ) );
	}
}
else
	add_action( 'admin_notices', 'wpps_requirementsError' );

?>