/sally/core/lib/Scaffold/modules/Constants/Constants.php

<?php

/**
 * Constants
 *
 * Allows you to use constants within your css by defining them
 * within @constants and then using a property list.
 *
 * You can set CSScaffold constants using XML. This allows you to create
 * constants using a CMS or by any other means to tie it in with your CSS.
 *
 * XML must be in this format:

 	<?xml version="1.0" ?>
 	<constants>

 		<constant>
 			<name>Foo</name>
 			<value>Bar</value>
 		</constant>

 	</constants>
 *
 * By default, it requires a constants.xml file in the root of the CSS directory.
 * You can change this in the plugins config.
 *
 * @author  Anthony Short
 * @license BSD License
 */
class Constants
{
	/**
	 * Stores all of the constants for the app
	 *
	 * @var array
	 */
	public static $constants = array();

	/**
	 * The pre-processing function occurs after the importing,
	 * but before any real processing. This is usually the stage
	 * where we set variables and the like, getting the css ready
	 * for processing.
	 *
	 * @author Anthony Short
	 * @param $css
	 */
	public static function pre_process()
	{
		# Global Constants
		self::set_global_constants();

		# XML Constants
		self::load_xml_constants( Scaffold::$config['Constants']['xml_path'] );

		# If there are some constants, let do it.
		if( $found = Scaffold::$css->find_at_group('constants') )
		{
			# Create our template style constants
			foreach($found['values'] as $key => $value)
			{
				# Check if this contains other constants
				$value = self::replace($value);

				# Set it
				self::set($key, $value);
			}
		}
	}

	/**
	 * Replaces the constants
	 *
	 * @return void
	 */
	public static function process()
	{
		Scaffold::$css->string = self::replace(Scaffold::$css->string);
	}

	/**
	 * Sets the global constants
	 *
	 * @return void
	 */
	private static function set_global_constants()
	{
		foreach(Scaffold::$config['Constants']['global'] as $key => $value)
		{
			self::set($key,$value);
		}
	}

	/**
	 * Sets constants
	 *
	 * @author Anthony Short
	 * @param $key
	 * @param $value
	 * @return null
	 */
	public static function set($key, $value = "")
	{
		# So we can pass through a whole array
		# and set them all at once
		if(is_array($key))
		{
			foreach($key as $name => $val)
			{
				self::$constants[$name] = $val;
			}
		}
		else
		{
			self::$constants[$key] = $value;
		}
	}

	/**
	 * Unsets a constant
	 *
	 * @param $key
	 * @return void
	 */
	public static function remove($key)
	{
		unset(self::$constants[$key]);
	}

	/**
	 * Returns the constant value
	 *
	 * @author Anthony Short
	 * @param $key
	 * @return string
	 */
	public static function get($key)
	{
		return self::$constants[$key];
	}

	/**
	 * Replaces all of the constants in a CSS string
	 * with the constants defined in the member variable $constants
	 * using PHP's interpolation.
	 */
	public static function replace($css)
	{
		# Pull the constants into the local scope as variables
		extract(self::$constants, EXTR_SKIP);

		# Remove unset variables from the string, so errors aren't thrown
		foreach(array_unique( Scaffold_Utils::match('/\{?\$([A-Za-z0-9_-]+)\}?/', $css, 1) ) as $value)
		{
			if(!isset($$value))
			{
				Scaffold::error('Missing constant - ' . $value);
			}
		}

		$css = stripslashes( eval('return "' . addslashes($css) . '";') );

		# Replace the variables within the string like a normal PHP string
		return $css;
	}

	/**
	 * Loads constants from an XML file
	 *
	 * @param $param
	 * @return return type
	 */
	private static function load_xml_constants($file)
	{
		if($file === false)
			return;

		# If the xml file doesn't exist
		if(!file_exists($file))
		{
			Scaffold::log("Missing constants XML file. The file ($file) doesn't exist.",1);
			return;
		}

		# Load the xml
		$xml = simplexml_load_file($file);

		# Loop through them and set them as constants
		foreach($xml->constant as $key => $value)
		{
			self::set((string)$value->name, (string)$value->value);
		}
	}

}