[Tex/LaTex] Error on linking email addresses inside elsarticle template

elsarticlehyperref

I am perplexed by the error:

 Use of \@uad doesn't match its definition.
\kernel@ifnextchar ...rved@d =#1\def \reserved@a {
                                                  #2}\def \reserved@b {#3}\f...
l.11 ...iversity.edu}{mailto:a2@myuniversity.edu}}

Arising in the following minimal tex file using the standard elsarticle class:

\documentclass{elsarticle}
\usepackage{hyperref}
\begin{document}
\begin{frontmatter}
\title{Remarks on something interesting}

\author[myu]{Author 1}
\ead{a1@myuniversity.edu}

\author[myu]{Author 2 \corref{cor1}}
\ead{\href{mailto:a2@myuniversity.edu}{mailto:a2@myuniversity.edu}}

\address[myu]{My Department, My Building, My University in My City}

\cortext[cor1]{Corresponding author}
\end{frontmatter}

\maketitle

A \href{http://google.com}{link to google.com}

\end{document}

It looks as though the class file doesn't support \href arguments here, but it is not obvious to me why that is. So, I'm left with several questions:

What does this error mean?
How I might go about modifying either the .tex or the .cls file so that the above can be compiled successfully?

I've taken a look at where \ead is defined in the class field but lack the tex-foo to figure out what's going on. I believe the relevant lines are:

\def\ead{\@ifnextchar[{\@uad}{\@ead}}
\gdef\@ead#1{\bgroup\def\_{\string\_}\def\{{\string\{}%
   \def\}{\string\}}%
   \edef\tmp{\the\@eadauthor}
   \immediate\write\@auxout{\string\emailauthor
     {#1}{\expandafter\strip@prefix\meaning\tmp}}%
  \egroup
}

The error seems like it might be related to how and where tex defines macros, but that is a bit over my head.

Background: Not directly relevant to this question, but sometimes context is useful. I encounter this when trying to use the elsarticle template in RStudio's rmarkdown, which uses pandoc with the option autolink_bare_uris which apparently cannot be turned off. This forces pandoc to transform bare emails into href'd ones, rather annoyingly breaking this template.

Best Answer

The \ead command in elsarticle writes the \emailauthor command to the aux file with the passed email address and the associated author as arguments. On subsequent runs, the aux file is read and the \emailauthor command is executed. The issue with adding \href as you have tried is that the \immediate\write\@auxout tries to expand it prior to writing the contents to the aux file, resulting in the error. As we want \href to be written to the aux file, you can do what you are after by prefacing \href with \string or \noexpand. For example:

\ead{\string\href{mailto:a2@myuniversity.edu}{a2@myuniversity.edu}}

You can check the aux file to see the following line (as expected):

\emailauthor{\href{mailto:a2@myuniversity.edu}{a2@myuniversity.edu}}{Author 2 \corref {cor1}}

Additionally, you can automate hyperlinking for all author emails and urls by modifying \@ead and \@uad, repsectively, with the following:

\usepackage{etoolbox}
\makeatletter%placed AFTER \usepackage{hyperref}, if to be used
    \newif\ifhyperrefloaded\hyperrefloadedfalse
    \@ifpackageloaded{hyperref}{\hyperrefloadedtrue}{\hyperrefloadedfalse}%check if hyperref is loaded
    \ifhyperrefloaded%
        \patchcmd{\@ead}{#1}{\string\href{mailto:#1}{#1}}{}{}
        \patchcmd{\@uad}{#2}{\string\url{#2}}{}{}\fi
\makeatother

The \ifhyperrefloaded is used to so that the \patchcmd calls are in the global scope and only used if the hyperref package is loaded.

Finally, I took the liberty of removing the mailto: from the displayed portion of \href and the unnecessary \maketitle from your MWE.

The result:

\documentclass{elsarticle}
\usepackage{hyperref}
\usepackage{etoolbox}

\makeatletter%placed AFTER \usepackage{hyperref}, if to be used
    \newif\ifhyperrefloaded\hyperrefloadedfalse
    \@ifpackageloaded{hyperref}{\hyperrefloadedtrue}{\hyperrefloadedfalse}%check if hyperref is loaded
    \ifhyperrefloaded%
        \patchcmd{\@ead}{#1}{\string\href{mailto:#1}{#1}}{}{}
        \patchcmd{\@uad}{#2}{\string\url{#2}}{}{}\fi
\makeatother
\begin{document}
\begin{frontmatter}
\title{Remarks on something interesting}

\author[myu]{Author 1}
\ead{a1@myuniversity.edu}

\author[myu]{Author 2 \corref{cor1}}
\ead{a2@myuniversity.edu}
\ead[url]{www.google.com}

\address[myu]{My Department, My Building, My University in My City}

\cortext[cor1]{Corresponding author}
\end{frontmatter}

A \href{http://google.com}{link to google.com}

\end{document}

Related Solutions

[Tex/LaTex] elsarticle class not displaying email addresses

Although I agree that it is not clear from the documentation or the 8th entry in the FAQ pointed out by Werner, all the templates use \title, \author, \ead etc after \begin{document} and \begin{frontmatter}.

The reason it does not work before \begin{document} is that (for some reason), it writes the email addresses to the aux file (which means it needs two runs), and the aux file doesn't get read and re-opened for writing until \begin{document} (so in fact you see lines like \emailauthor{a1@myuniversity.edu}{Author 1} appearing on the terminal instead of getting written to the aux file).

Note that the frontmatter environment does nothing except \maketitle at the end (and some grouping), so I guess the supported syntax is to replace your \maketitle with the frontmatter environment. I have also done this in the following modification of your example.

I have also deleted the unwanted space between the author name and \corref.

Remember that you need to compile twice to see the e-mail addresses.

\documentclass{elsarticle}
\begin{document}

\begin{frontmatter}
\title{Remarks on something interesting}

\author[myu]{Author 1}
\ead{a1@myuniversity.edu}

\author[myu]{Author 2\corref{cor1}}
\ead{a2@myuniversity.edu}

\address[myu]{My Department, My Building, My University in My City}

\cortext[cor1]{Corresponding author}

\end{frontmatter}

\end{document}

Image of footer displaying the e-mail addresses (inspired by Gonzalo Medina's previous answer):

Image of footer

Problem adding multiple author in elsarticle template

Welcome! I copied your code in overleaf and deleted the space for \author[1,3]{Kwangnam Yu} between the 1 and 3 and it gives the address as c.

\documentclass[5p,twocolumn, times]{elsarticle}

\usepackage{lineno,hyperref}
\usepackage{xcolor}
\usepackage[hyphens]{xurl}
\modulolinenumbers[5]

\journal{Journal of \LaTeX\ Templates}
\bibliographystyle{elsarticle-num}
\begin{document}

\begin{frontmatter}

\title{Title}
\author[1,2]{Byeoungju Lee}
\author[1,3]{Kwangnam Yu}
\author[4]{Jiwon Jeon}

\author[1]{E. J. Choi\corref{mycorrespondingauthor}}
\cortext[mycorrespondingauthor]{Corresponding author}
\ead{[email protected]}

\address[1]{Department of Physics, University of Seoul, Seoul 130-743, Korea}
\address[2]{Department of Smart City, University of Seoul, Seoul 130-743, Korea}
\address[3]{SK Siltron Inc., 132-11, 3gongdan 3-ro, Gumi-si, Gyeongsangbuk-do 39400, South 
 Korea}
\address[4]{NSRI(Natural Science Research Institute), University of Seoul,  Seoul 130-743, 
 Korea}

\begin{abstract}
Abstract
\end{abstract}

\end{frontmatter}
article body
\end{document}

Best Answer

Related Solutions

[Tex/LaTex] elsarticle class not displaying email addresses

Problem adding multiple author in elsarticle template

Related Question