[luatex] Creating a token list

[Javier Bezos]

I wrote:

> How can I create a token list to feed a "write"
> whatsit? For example, let's suppose I want to write
> \string\doit{\the\lastypos}.

:-/ Is there no way? Well, I can define a box with a
\write and then inspect the node (and it works with
some caveats), but there must be a pure lua solution.

Javier