Paracol 包：未定义的环境

Question

我得到了LaTeX Error: Environment leftcolumn* undefined下一个 MWE：

\documentclass{article}
\usepackage{paracol}

\begin{document}

\begin{leftcolumn*}
\subsection{%
Environments \texttt{leftcolumn} and\\
\texttt{rightcolumn}}
The environments |leftcolumn| and
|rightcolumn| (and their starred versions
with an optional argument) are available as
more convenient means than saying
|\begin{nthcolumn}{0}| to switch to the
left(most) column and ...
\begin{figure*}...\end{figure*}
\begin{figure}[t]...\end{figure}
\end{leftcolumn*}
\begin{rightcolumn}
source and a figure env
\end{rightcolumn}

\end{document}

这很奇怪，所以我不知道如果你编译它，它是否会没问题。我会展示证据截图。

Answer 1

该包的文档没有清楚地说明这一点，但似乎您需要将其描述的所有环境都包含在一个paracol环境中：

\documentclass{article}
\usepackage{paracol}

\begin{document}
\begin{paracol}{2}
\begin{leftcolumn*}
\subsection{%
Environments \texttt{leftcolumn} and\\
\texttt{rightcolumn}}
The environments |leftcolumn| and
|rightcolumn| (and their starred versions
with an optional argument) are available as
more convenient means than saying
\verb|\begin{nthcolumn}{0}| to switch to the
left(most) column and ...
\begin{figure*}...\end{figure*}
\begin{figure}[t]...\end{figure}
\end{leftcolumn*}
\begin{rightcolumn}
source and a figure env
\end{rightcolumn}
\end{paracol}
\end{document}

（我还修复了逐字代码，否则会导致错误。）