Using \usebox inside a \newcommand

Question

I have this code:

%Abstracts
\newcommand{\@spanishabstractname}{{\bfseries Resumen}}
\newsavebox\@sabstract
\newenvironment{spanishabstract}{%
    \lrbox\@sabstract\minipage{1\textwidth}\selectlanguage{spanish}\itshape}%
    {\endminipage\endlrbox\normalfont}

\newcommand{\@englishabstractname}{{\bfseries Abstract}}
\newsavebox\@eabstract
\newenvironment{englishabstract}{%
    \lrbox\@eabstract\minipage{1\textwidth}\selectlanguage{english}\itshape}%
    {\endminipage\endlrbox\normalfont}

%Making Title
\newcommand{\maketitle}{%
    \twocolumn[%
    {\centering \@spanishabstractname\par}\linespace
    \noindent\usebox{\@sabstract}\par\linespace
    \@skeyw\par\onecmskip
    {\centering \@englishabstractname\par}\linespace
    \noindent\usebox{\@eabstract}\par\linespace
    \@ekeyw
    ]
}

But when I use the command \maketitle in the document, not shows the boxes \@sabstract and \@eabstract, as follows.

If I put the code definition of \maketitle in a \AtEndDocument:

\AtEndDocument{%
    \twocolumn[%
    {\centering \@spanishabstractname\par}\linespace
    \noindent\usebox{\@sabstract}\par\linespace
    \@skeyw\par\onecmskip
    {\centering \@englishabstractname\par}\linespace
    \noindent\usebox{\@eabstract}\par\linespace
    \@ekeyw
    ]
}

Everything works perfectly!

How I can fix this? Why wrong? Thanks!

Answer 1

The box is defined in a group (the environment), so it won't be available outside it. You need to set it globally:

\newcommand{\@spanishabstractname}{{\bfseries Resumen}}
\newsavebox\@sabstract
\newenvironment{spanishabstract}
  {\begin{lrbox}{8}
   \minipage{1\textwidth}\selectlanguage{spanish}\itshape}
  {\endminipage\end{lrbox}\global\setbox\@sabstract\box8 }

Similarly for the English abstract.

Using \lrbox and \endlrbox is not recommended. I would put the \bfseries instruction later (after \centering), not in the definition of \@spanishabstractname.

Answer 2

I tried to create a MWE whereby the following commands I don't know:

• \@ekeyw
• \@skeyw
• \linespace

Here the MWE

\documentclass{article}
\usepackage[spanish,english]{babel}
\usepackage{blindtext}
\makeatletter
%Abstracts
\newcommand{\@spanishabstractname}{{\bfseries Resumen}}
\newsavebox\@sabstract
\newenvironment{spanishabstract}{%
    \lrbox\@sabstract\minipage{1\textwidth}\selectlanguage{spanish}\itshape}%
    {\endminipage\endlrbox\normalfont}

\newcommand{\@englishabstractname}{{\bfseries Abstract}}
\newsavebox\@eabstract
\newenvironment{englishabstract}{%
    \lrbox\@eabstract\minipage{1\textwidth}\selectlanguage{english}\itshape}%
    {\endminipage\endlrbox\normalfont}

%Making Title
\renewcommand{\maketitle}{%
    \twocolumn[%
    {\centering \@spanishabstractname\par}
    \noindent\usebox{\@sabstract}\par
    \par
    {\centering \@englishabstractname\par}
    \noindent\usebox{\@eabstract}\par
    ]
}
\makeatother

\begin{document}
\begin{spanishabstract}
\blindtext
\end{spanishabstract}
\begin{englishabstract}
\blindtext
\end{englishabstract}

\maketitle
\end{document}