[luatex] whatsit generation

[Frank Mittelbach]

Hi Hans

>
> in current luatex user defined nodes have subtype 8

yeah well, as you know my program is currently TL2015 based (ie .085 ) 
for some reason :-)
>
> 116 refers to tables that contain a token list (a table of triplets
> starting with a ref count dummy) which is probably not that useful

yes, looks like it

> as i was sure that at some point we added a lua table type too i checked
> the manual and found out that we don't actually mantion it there
>
> the magic type number is 108

cool, just what I was looking for. I need to pass several values and in 
that case using the number type is not so good, right now I used string 
and decompose afterwards but a table is better

thanks
frank