[texhax] On putting \unvbox inside an \hbox

[Michael Barr]

No, I am not trying to answer the question.  But it reminds me of a web 
site I saw recently: 
http://homepage.ntlworld.com/jonathan.deboynepollard/FGA/put-down-the-chocolate-covered-banana.html
that contains a sidebar that says, in part:

The general case is:

   1.  Someone wants to accomplish task Y.
   2.  They determine that a way to accomplish Y is to use facility X.
   3.  There is a sub-task of Y, say Z, for which X is ill-suited.
   4.  They come into the group and ask .how can I use X to accomplish Z?.

This is a problem for people here trying to answer the real question, 
which is:

     How can I accomplish Y?

But nobody can answer this question because the querent never mentioned
Y at all, and so nobody knows that the real goal is to accomplish Y..

-- Mark-Jason Dominus.

This URL ought to be part of every texhax issue, since it expresses this 
sort of problem so well.  Why do you want to put \unvbox inside an \hbox? 
After all, the following works perfectly well:

\documentclass{article}
  \pdfoutput0
\begin{document}
  \setbox0=\vbox{test}
  \setbox2=\hbox{\box0}
  \box2

\end{document}

Michael Barr