unpack() behaviour not as documented

[Sam Roberts <vieuxtech@...>]

Unpack's docs say unpack(t, i, j) does "return t[i], t[i+1], ...,
t[j]", but I don't think it does this. Example follows.

Generally, I don't see any way in lua to return a variable number of
arguments, when some of those arguments will be nil.

Can anybody suggest a way to implement the following so it works as intended?

Cheers,
Sam

=========================
stuff = {red=1, green=2, blue=3}

function get_stuff(...)
    local r = {}
    for i,k in ipairs{...} do
        r[i] = stuff[k]
    end
    return unpack(r, 1, #...) -- #... is 3 when there are 3 args to
this function
end

red, magenta, green = get_stuff("red", "magenta", "green")

print(stuff.red, " should eql ", red)
print(stuff.magenta, " should eql ", magenta)
print(stuff.blue, " should eql ", blue) -- but the [3] was not returned