<?php
/**
 * @author Sori Lee <sori24 (at) gmail (dot) com>
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License 2.0 or later
 */

if(!defined('MEDIAWIKI'))
    die("This is an extension to the MediaWiki package and cannot be run standalone.");

// Register as an extention
$wgExtensionCredits['parserhook'][] = array(
	'name' => 'DollarSign',
	'version' => '1.0',
	'url' => 'https://www.mediawiki.org/wiki/Extension:DollarSign',
	'author' => 'Sori Lee',
	'description' => 'Allows to recognize the LaTeX-style inline math mode with dollar signs',
);

// Register hooks
$wgHooks['ParserBeforeInternalParse'][] = 'dsParse';

// Parse function
function dsParse( &$parser, &$text, &$stripState ) {
	// We replace '$...$' by '<math>...</math>' and '\$' by '$'.
	$pattern = array('/([^\\\\]|^)\$([^\$]*)\$/', '/\\\\\$/');
	$replace = array('$1<math>$2</math>', '\$');

	// Perform the substitution.
	$text = preg_replace($pattern, $replace, $text);

	return true;
}