Lua variable inspectation

#!/usr/bin/env lua

do
    local outside = "abc"
    function test()
        local inside = "def"

        return tostring(outside .. inside)
    end
end

-- higher poll-every = less slowdown, but may miss changes, or the entire in scope var
-- lower ppoll-every = more slowdown, but less likley to miss a variable change
function inspect_inside(vars, poll_every, func, ...)
    local variables = {}

    local hook = function()
        local idx = 1
        while true do
            local ln, lv = debug.getlocal(2, idx)
            if ln ~= nil then
                variables[ln] = lv
            else
                break
            end
            idx = 1 + idx
        end
    end

    local oldhook = debug.gethook()
    debug.sethook(hook, "", poll_every)
        local func_rets = {func(...)}
    debug.sethook(oldhook)

    local ret = {}
    for k,v in ipairs(vars) do
        ret[v] = variables[v]
    end
    return ret, unpack(func_rets)
end

function inspect_outside(vars, func)
    local upvals = {}

    local i = 1
    while true do
        local name, val = debug.getupvalue(func, i)
        if not name then break end

        upvals[name] = val
        i = i + 1
    end

    local ret = {}
    for k,v in ipairs(vars) do
        ret[v] = upvals[v]
    end
    return ret
end

-- WARNING, POLLEVERY = 1, SLOW AS HELL, INCREASE UNTIL IT'S STABLE!
print(inspect_inside({"inside"}, 1, test).inside)
-- try and cache the result from this
print(inspect_outside({"outside"}, test).outside)