How to implement Certified Random in LaTeX

Question

What is the best way of implementing Certified Random coauthors in LaTeX. There is one potential implementation from the comp.text.tex usenet group that uses perltex and can be modified as follows:

\usepackage{perltex}

\perlnewcommand{\shuffleauthors}[1]{
@authlist = split /\\.*?\{c\}/, $_[0];
foreach (1 .. 3) {
foreach $i (0 .. $#authlist) {
$r = int(rand(@authlist));
($authlist[$i], $authlist[$r]) = ($authlist[$r], $authlist[$i]);
}
}
return join(" \\textcircled{r} ", @authlist);
}

\title{Test of Random Authors}
\author{\shuffleauthors{Arthur Won \and Ardur Tu \and Auzer Trea}}

\begin{document}
\maketitle

\end{document}

Unfortunately \thanks footnotes do not work in this implementation and I'm not enough of a latex coder to get it to work. Moreover, the ideal implementation would not require perltex.

Answer 1

You can use expl3:

\documentclass{article}
\usepackage{xparse}

\ExplSyntaxOn
\NewDocumentCommand{\shuffleauthors}{m}
 {
  \seq_set_split:Nnn \l_tedto_shuffle_authors_seq { \and } { #1 }
  \seq_shuffle:N \l_tedto_shuffle_authors_seq
  \seq_use:Nn \l_tedto_shuffle_authors_seq { \and }
 }
\seq_new:N \l_tedto_shuffle_authors_seq
\ExplSyntaxOff

\begin{document}

\title{Test of Random Authors}
\author{\shuffleauthors{%
  Arthur Won\thanks{Supported by somebody} \and Ardur Tu \and Auzer Trea%
}}

\maketitle

\end{document}

If you want to add \textcirled{r} after every author, you have to modify the behavior of \thanks that typesets the mark in a zero width box.

\documentclass{article}
\usepackage{xparse,etoolbox}

\patchcmd{\maketitle}{\rlap}{\mbox}{}{} % we want \thanks not to occupy zero width

\ExplSyntaxOn

\NewDocumentCommand{\shuffleauthors}{m}
 {
  \seq_set_split:Nnn \l_tedto_shuffle_authors_seq { \and } { #1 }
  \seq_shuffle:N \l_tedto_shuffle_authors_seq
  \seq_use:Nn \l_tedto_shuffle_authors_seq { \,\textcircled{r}\and }
  \,\textcircled{r}
 }
\seq_new:N \l_tedto_shuffle_authors_seq

% fix the seed
\sys_gset_rand_seed:n { 42 }

\ExplSyntaxOff

\begin{document}

\title{Test of Random Authors}
\author{\shuffleauthors{%
  Arthur Won\thanks{Supported by somebody} \and Ardur Tu \and Auzer Trea%
}}

\maketitle

\end{document}

I also added how to ensure constant typesetting, by setting a seed.