function startsWith(str, prefix)
	return string.sub(str, 1, #prefix) == prefix
	end
	function endsWith(str, suffix)
	return string.sub(str, -#suffix) == suffix
	end
	function isNaN(x)
	if(x == nil) then return false end
	if(type(x) == "userdata") then
	if x.type ~= nil and startsWith(tostring(x), "vec") then
	for i = 1, x:getLength() do
	if(isNaN(x[i])) then return true end
	end
	return false
	end
	end
	return x ~= x
	end