[texhax] \newcommand

[Barbara Beeton]

roger,
you've fallen into a most common patch of quicksand.

control sequences containing @ signs are "internal" ones,
and must be given special attention.  the fix, fortunately,
is simple.  two possibilities:

 - put your new command in a file named whatever.sty and
   then \usepackage{whatever}

 - leave the definition in the preamble of your document
   and surround it by the commands
     \makeatletter
     ...
     \makeatother

this is almost certainly described in the very fine uktug
faq; i think the url is
    http://www.tex.ac.uk/faq/
(you really should become acquainted with the faq -- it's
worth your effort.)
							-- bb

---------- Original message ----------
Date: Thu, 25 Sep 2003 16:45:33 -0230 (NDDT)
From: Roger Mason <rmason at sparky2.esd.mun.ca>
To: texhax at tug.org
Subject: [texhax] \newcommand

Hello,

I am trying to define a command in latex with this code in the preamble:

\newcommand{\mybox}[2]{%
  \setlength{\unitlength}{1pt}
  \makeatletter
  \begin{picture}(\strip at pt\linewidth,#1)
    \put(0,0){\framebox(\strip at pt\linewidth,#1)[tl]{#2}}
  \end{picture}
  \makeatother}

It is designed to produce a box that is the width of the \linewidth
currently in use at height #1 containing text #2.  The code in the
definition was obtained from the archives of this list and runs fine when
embeded in a LaTeX document (with numbers for #1 & #2).  When I define the
command above and invoke it using (for example)

\mybox{72}{Zn}

in the body of the document, compilation fails and the log file says:

! Undefined control sequence.
<argument> \strip
                  @pt\linewidth
l.90 \mybox{72}{Zn}

The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

Is there some simple step I am missing?

Thanks for any replies,

Roger Mason

P.S. Is it considered good etiquette on this list to thank responders on
the list or should that be done privately?