Removing holes from a list

[Dirk Laurie <dirk.laurie@...>]

For example:

list=table.pack(1,2,3,nil,4,5,nil,nil,6,7)

I have several ugly methods that work, e.g. operate
with two indices inside a while loop until one reaches
list.n, make a new table containing the non-nil entries
and assign it to `list`.

Does anyone have a method that deserves to be
called elegant?