What Does This Code Do? [Resolved, Comments Welcome]

[Travis G]

function compare($var1,$var2)
{
	$string = "if($var1 $var2)
	{
		\$res=1;
	}
	else
	{
		\$res=0;
	}";

	eval("$string;");
	return $res;
}

I'm trying to make sense of this code in this busted PHP application at work. Just to give you an idea, this function is usually called compare("foo", "==bar") . The quotes around the if blocks, the lack of a logic operator, the dereferencing of $res, the random eval(), I don't get it.