[texhax] How to use a created box's dimensions to place subsequent text?

[W. Craig Carter]

Hello,

I am trying to do something fairly simple (I think) but am 
becoming bit impatient with the tex manuals. Can anyone get me on 
the right track?

I want a command such as \setover{text text text}{b}, similar to 
\underbrace{}{}, but in paragraph mode. "text text text" should be 
in an \hbox at the same height as the current line, and "b" should 
be centered below "text text text"  It would also be nice to have 
the option of putting at "\upbracefill" between the "text text text" 
and the "b."


I started by hacking the \upperbrace definition, but am getting 
nowhere...

Should I be using a \parbox-\savebox-usebox construction from LaTeX 
(if so, how do I get the box dimensions to place text?), or should I 
be using \vbox{\hbox{}\upbracefill\hbox{}}. If so I need to \kern 
according to size of boxes...

If I only had a working version to improve!


Thanks,

C Carter