table.sort (table [, comp])table[1] to table[n],
where n is the length of the table.
If comp is given,
then it must be a function that receives two table elements,
and returns true
when the first is less than the second
(so that not comp(a[i+1],a[i]) will be true after the sort).
If comp is not given,
then the standard Lua operator < is used instead.
The sort algorithm is not stable; that is, elements considered equal by the given order may have their relative positions changed by the sort.