Problem with the \@whilenum

Question

I met the error You can't use `\spacefactor' in vertical mode. when using \@whilenum for a loop. Below is a minimum not-working example. Why is this wrong?

\documentclass{article}
\usepackage[utf8]{inputenc}
\title{loop}\author{}
\begin{document}
\maketitle
\@whilenum\value{section}<6\do{\section{more}}
\end{document}

Error Message

You can't use `\spacefactor' in vertical mode.
\@->\spacefactor 
                 \@m {}
l.6 \@
      whilenum\value{section}<6\do{\section{more}}
Sorry, but I'm not programmed to handle this case;
I'll just pretend that you didn't ask for it.
If you're in the wrong mode, you might be able to
return to the right one by typing `I}' or `I$' or `I\par'.
! Missing $ inserted.
<inserted text> 
                $
l.6 @
      whilenum\value{section}<6\do{\section{more}}
I've inserted a begin-math/end-math symbol since I think
you left one out. Proceed, with fingers crossed.

the @ is not a valid character in a macro name (at least not in a .tex file), so you need to make it valid with \makeatletter before you intend to use it. — Lupino, Dec 11 '22 at 04:34
@Lupino I converted your commend into a community answer. If you are not happy with that then let me know and I delete it. — Dr. Manuel Kuehner, Dec 11 '22 at 04:54

score 1 · Accepted Answer · answered Dec 11 '22 at 04:53

Following user Lupino's comment, I provide the following community answer. Please refer to What do \makeatletter and \makeatother do? for information regarding \makeatletter and \makeatother.

\documentclass{article}
\usepackage[utf8]{inputenc}
\title{loop}\author{}
\begin{document}
\maketitle
\makeatletter % <-- Added
\@whilenum\value{section}<6\do{\section{more}}
\makeatother % <-- Added
\end{document}

Problem with the \@whilenum

Error Message

1 Answers1