增加段落间距

Question

我写了一个小环境来写练习：

\documentclass{book}
\usepackage{lipsum}
\usepackage{tocloft}
\usepackage{xparse}

\newcommand{\listofexercises}{List of exercises}
\newlistof{exercise}{exp}{\listofexercises}

% Restart counter at each new chapter
\makeatletter
\@addtoreset{exercise}{chapter}
\makeatother

% Exercise environment
\newenvironment{exercise}[1][]{%
    \refstepcounter{exercise}
    \par\noindent\textbf{Exercice \thechapter.\theexercise} {#1}
    \newline
    \addcontentsline{exp}{exercise}{%
        Exercice \thechapter.\theexercise
        \ifx&#1&\else\ -- #1\fi
    }\par
}{
    \newline%
}

\begin{document}

\mainmatter

\chapter{Foo}

\lipsum[1][1-3]

\begin{exercise}
What is the difference between a duck?
\end{exercise}

\lipsum[2][1-3]

\begin{exercise}
What is the answer to life the universe and everything?
\end{exercise}

\begin{exercise}[Don't answer yes]
Are you human?
\end{exercise}

\chapter{Bar}

\begin{exercise}[Impossible?]
If you enjoy wasting time, is that time really wasted?
\end{exercise}

\backmatter

\listofexercise

\end{document}

遗憾的是，间距无法帮助清楚地识别练习。家长很困惑，间距也不好。

一些解决方法是不对整个文档设置 parindent 并\newline在环境后添加 double，但我不认为这是一个好的解决方案。

此外，如果我在练习后添加新行，我会得到一个错误。使用这个：

\begin{exercise}
What is the answer to life the universe and everything?

\end{exercise}

我明白了：

! LaTeX Error: There's no line here to end.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              
                                                  
l.44 \end{exercise}

Answer 1

我确信这可以做得更漂亮。我的第一个想法是这样的。

除了par-command 之外，您还可以使用\par\addvspace{\baselineskip}：

\documentclass{book}
\usepackage{lipsum}
\usepackage{tocloft}
\usepackage{xparse}
\usepackage{parskip}

\newcommand{\listofexercises}{List of exercises}
\newlistof{exercise}{exp}{\listofexercises}

% Restart counter at each new chapter
\makeatletter
\@addtoreset{exercise}{chapter}
\makeatother

% Exercise environment
\newenvironment{exercise}[1][]{%
    \refstepcounter{exercise}
    \par\addvspace{\baselineskip}\noindent\textbf{Exercice \thechapter.\theexercise} {#1}
    \par
    \addcontentsline{exp}{exercise}{%
        Exercice \thechapter.\theexercise
        \ifx&#1&\else\ -- #1\fi
    }\par
}{
    % \newline%
}

\begin{document}

\mainmatter

\chapter{Foo}

\lipsum[1][1-3]

\begin{exercise}
What is the difference between a duck?
\end{exercise}

\lipsum[2][1-3]

\begin{exercise}
What is the answer to life the universe and everything?
\end{exercise}

\begin{exercise}[Don't answer yes]
Are you human?
\end{exercise}

\chapter{Bar}

\begin{exercise}[Impossible?]
If you enjoy wasting time, is that time really wasted?
\end{exercise}

\backmatter

\listofexercise

\end{document}