varargs & table.insert()?

[PA <petite.abeille@...>]

Hello,

The more I try to use varargs, the more confused I get :/

Considered the following scenario: one would like to insert an 
additional argument into a varargs...

For example:

local List = function( ... )
    return { n = select( '#', ... ), ... }
end

local aList = List( nil, 'a', nil )

for anIndex = 1, aList.n do
    print( '>', anIndex, aList[ anIndex ] )
end

>       1       nil
>       2       a
>       3       nil

Ok... 3 arguments... in the right order... now lets try to insert an 
additional value:

table.insert( aList, 'first' )
aList.n = aList.n + 1

>       1       first
>       2       a
>       3       nil
>       4       nil

Oh, no! 4 mangled arguments :(

Lets try something else:

aList = { n = aList.n + 1, 'first', unpack( aList, 1, aList.n ) }

>       1       first
>       2       nil
>       3       a
>       4       nil

Looks better... but only works when adding a leading argument...

So... how does one properly manipulate varargs constructs?!?!?

Thanks in advance.

Cheers,

PA.