table.rotate should use the triple reverse method.

[Parakleta]

The existing shift/push method touches every element in the table once per step. The triple reverse method touches every element exactly twice.

function tablex.rotate(t, n)
    local tlen = #t
    local mid = -n % tlen
    tablex.reverse(t)
    tablex.reverse(t, 1, mid)
    tablex.reverse(t, mid+1, tlen)
end

For this to work your tablex.reverse needs to take optional bound arguments. Note that tablex.reverse should also be caching the length value rather than recalculating it in the loop.

[1bardesign]

should probably branch on n being 1 or not, because that's the most common case in my experience and it'd be strictly slower there.

i think i'd probably prefer tablex.reverse_span rather than reverse itself taking optional arguments, so the intent is clear.

i'm fine with this change otherwise 👍