MarkupExpressionSamples

$MarkupExpr['calc'] = 'MxCalc($args)';
function MxCalc($args) {
	global $MxCalcChars, $MxCalcFunc1, $MxCalcFunc2;
	//allowed characters (operators, digits, brackets etc) apart from function names below
	SDV($MxCalcChars, "/^[-+*,\\/% ><=()0-9.^]+$/");
	//math functions with single argument
	SDV($MxCalcFunc1, array(
		'sqrt','sin','cos','tan','asin','acos','atan','log',
		'abs','ceil','floor','round','deg2rad','rad2deg',
	));	
	//math functions with 2 or more arguments, constants, and others
	SDV($MxCalcFunc2, array(
		'pow','max','min','rand','fmod','pi',
	));
	$mathfn = array_merge($MxCalcFunc1, $MxCalcFunc2); 
	$arg = implode(" ", $args);
	//nothing to do
	if ($arg == '') return "empty input!";
	//check if math expression has only allowed characters and function names
	$str = $arg;
	foreach($mathfn as $fn) {
		$str = str_replace($fn, '', $str);
	}
	if ($str!='' && !preg_match($MxCalcChars, $str, $m)) return "Input error!";
	//translate easy input
	$arg = str_replace('pi', M_PI, $arg);
	$arg = preg_replace("/(\\-?[\\d.]+)\\^(\\-?[\\d.]+)/", "pow($1, $2)", $arg);
	foreach($MxCalcFunc1 as $fn)
		$arg = preg_replace("/{$fn}\\s?(\\-?[\\d.]+)/", "{$fn}($1)", $arg);
	//do the work
	eval("\$res = $arg;");
	//provide for 0 as result from comparison operations
	if ($res=='')
		if (preg_match("/[><=]/", $arg))	$res = '0';
	return $res;
}

# unix time, seconds since 1970-01-01
$MarkupExpr['utime'] = 'MxUTime($args[0])';
function MxUTime($arg) {
        $udate = date('U', strtotime($arg));
        if ($arg=='now' || $arg=='') $udate = time();
        return $udate;
}

# unix time as days since 1970-01-01 to midnight of DATE entered
$MarkupExpr['udays'] = 'MxUDays($args[0])';
function MxUDays($arg) {
        $udate = date('U', strtotime($arg));
        if ($arg=='now' || $arg=='') $udate = time();
        return floor($udate/86400);
}

$MarkupExpr['catlist'] = 'CategoryList($pagename, $args[0], $args[1])';
function CategoryList($pn, $arg='', $sep=',') {
	global $CategoryGroup;
	if(!$arg=='') $pn = MakePageName($pn, $arg);
	if($sep==NULL) $sep = ",";
	$page = RetrieveAuthPage($pn, 'read', true);
	$pat = '/\\[\\[\\!(.*?)\\]\\]/';
	$text = preg_replace('/\\(:(.*?):\\)/' ,"", $page['text']);
	if(preg_match_all($pat, $text, $matches)) {
	foreach($matches[1] as $i=>$m)
		 $catlist[] = MakePageName($pn, $CategoryGroup.".".$m);
	return implode($sep, $catlist);
	}
}