stringmod

local strmt = getmetatable("a")
if type(strmt.__index) ~= "table" then
    print("String[n]: Unable to load twice; or other stuff has already hooked onto strings.")
else
    local origindex = strmt.__index
    function strmt:__index(k)
        if type(k) == "number" then
            if k > string.len(self) or k < 1 then
                return nil
            else
                print("DEBUG: !", self, k)
                return string.sub(self,k, k)
            end
        end
        return origindex[k]
    end
end