enumitem - 描述环境中多行标签的对齐

Question

我正在尝试使多行标签右对齐。我将style=multiline和align=right选项应用于 enumitem 描述环境。以下是描述问题的代码：

\documentclass{article}

\usepackage{geometry}
\usepackage{enumitem}

\begin{document}

% multiline, left-aligned
\begin{description}[style=multiline, leftmargin=!, labelwidth=4cm]
    \item[Truth-functional\\ connective] A sentence connective with the property that the truth value of the newly formed sentence is determined solely by the truth value(s) of the constituent sentence(s), nothing more.
\end{description}

% multiline, right-aligned; the option is not applied.
\begin{description}[align=right, style=multiline, leftmargin=!, labelwidth=4cm]
    \item[Truth-functional connective] A sentence connective with the property that the truth value of the newly formed sentence is determined solely by the truth value(s) of the constituent sentence(s), nothing more.
\end{description}

% the order of options changed; different result.
\begin{description}[style=multiline, align=right, leftmargin=!, labelwidth=4cm]
    \item[Truth-functional connective] A sentence connective with the property that the truth value of the newly formed sentence is determined solely by the truth value(s) of the constituent sentence(s), nothing more.
\end{description}

% The label aligned as intended with a single line label.
\begin{description}[align=right, leftmargin=!, labelwidth=4cm]
    \item[Truth-functional] A sentence connective with the property that the truth value of the newly formed sentence is determined solely by the truth value(s) of the constituent sentence(s), nothing more.
\end{description}

\end{document}

使用单行标签时，没有问题。但使用多行标签时，选项无法正常工作。只有第一个和最后一个选项按预期工作。这段代码中发生了什么？

期望的输出是

Answer 1

首先，让我们分析一下您的示例中发生了什么。为此，请注意，如enumitem的文档中所述，multiline相当于style=standard,align=parleft,labelwidth=!。

1. style=multiline, leftmargin=!, labelwidth=4cm

   它按预期工作：具有自动换行的固定宽度标签。由于 ，它是左对齐的parleft。

2. align=right, style=multiline, leftmargin=!, labelwidth=4cm

   style=multiline这与sets完全相同align=parleft，它会覆盖以前的设置。

3. style=multiline, align=right, leftmargin=!, labelwidth=4cm

   设置align=right实际上撤消了 的中心部分style=multiline（即创建 的部分\parbox）。我不确定为什么，但这会导致Infinite glue shrinkage我在运行您的示例时出错。您没有收到此错误吗？理论上，我本来希望这与下一个案例相同。

4. align=right, leftmargin=!, labelwidth=4cm

   这里你再次得到了你所期望的：右对齐，但没有\parbox。

---

那么我们如何得到你想要的东西？最直接的选择是创建一个新的对齐方式parright，它的作用与 相同parleft，但使用右对齐方式。我们可以从文档第 6 页复制定义并替换\raggedright为\raggedleft。

\documentclass{article}

\usepackage{geometry}
\usepackage{enumitem}

\SetLabelAlign{parright}{\strut\smash{\parbox[t]\labelwidth{\raggedleft#1}}}

\begin{document}

% multiline, left-aligned
\begin{description}[align=parright, leftmargin=!, labelwidth=4cm]
    \item[Truth-functional connective] A sentence connective with the property that the truth value of the newly formed sentence is determined solely by the truth value(s) of the constituent sentence(s), nothing more.
\end{description}

\end{document}