🚀 go-pugleaf

In article <1992Aug18.020840.20852@organpipe.uug.arizona.edu>, mjm@spekl.as.arizona.edu (Mark McCaughrean) writes...
> 
>     In the middle of an \halign, I want to use \noalign to set a
>paragraph of text (say). I want this paragraph to have the same
>width as the table I'm setting using \halign. 

A backwards answer: Use 
  \halign to <dimen>{...}.

>How do I get TeX
>to tell me what the width of the table is, i.e. the width of the
>vertical box I'm currently in the middle of? 

You can't.  The width is undefined until the box is wrapped up.

>(I don't want to use
>\multispan, by the way: I want the exact width of the table, and 
>I don't want to have to know how many columns to span).

\multispan doesn't tell you the width of the table anyway, and you
need to know the width in order to break the paragraph.

> 
>     I figured I could make a \setbox with an \hrule inside it,
>hoping the \hrule would be the width of the table, and that then
>I could use \wd to get the width of the box. I can't get it to
>work. 

It will never work.

>Seems like TeX must know the width though, or does it only
>work it out when it has digested the whole table?

Yes, of course!  It can't know the width of the table until all the entries 
are processed!

>     Any ideas? 

Check the width of the table after it is finished, and write the width to 
a file so the paragraph can be set properly the next time.  Or reprocess
the table with paragraph immediately.

Donald Arseneau         asnd@reg.triumf.ca