如何像對待常規文字一樣對待清單（關於垂直間距）？

Question

情境: 我想像對待垂直間距的常規文本一樣對待清單（逐項列出、列舉和描述）。即：

1. 如果清單開始一個段落，請\parskip預先插入垂直線 - 否則沒有垂直間距；
2. 列表項之間沒有垂直間距；
3. 如果清單以段落結尾，則\parskip在後面插入垂直線 - 否則沒有垂直間距。

我特別使用了以下信息\topsep、\itemsep、\partopsep 和 \parsep - 它們各自的意義是什麼。

需求 #1 已通過 解決\setlist{topsep=-\parskip,partopsep=\parskip}。

需求 #2 已通過 解決\setlist{noitemsep}。

問題： 要求#3 還存在兩個問題：

• 增加了垂直空間後如果後者開始一個段落，則該列表，即使該列表是立即地接下來是文字。 （即不存在獨立parbottomsep長度這樣的東西）。
• 如果一個新的段落在列表之後開始，本段落不是前面帶有\parskip.

問題： 如何遵守要求#3？
（我目前使用手動補丁 - 請參閱下面的 MWE - 但它當然不令人滿意。）

---

微量元素

\documentclass[parskip=half]{scrartcl}
    \usepackage{enumitem}
    \setlist{%
        topsep=-\parskip,
        partopsep=\parskip,
        noitemsep,
    }
\begin{document}
    This sentence is a paragraph on its own; there is thus a vertical parskip prior next paragraph.

    Following list is \emph{within} a paragraph, with preceding and appended text.
    \begin{itemize}
        \item One,
        \item Two,
        \begin{itemize}
            \item Two and a half;
            \item Almost three.
        \end{itemize}
        \item Three.
    \end{itemize}
    This text is appended to the previous list.
    However, following list starts a new paragraph on its own.

    \begin{enumerate}
        \item Did you notice the vertical spacing preceding this list?
        \item Two,
        \begin{enumerate}
            \item Two and a half;
            \item Almost three.
        \end{enumerate}
        \item Three.
    \end{enumerate}
%   \vspace{-\parskip}                                  %quick and dirty solution
    \textbf{There shouldn't be a vertical spacing here.}
    This text is appended to the previous list too.

    And finally, a list with preceding text only.
    \begin{itemize}
        \item One,
        \item Two,
        \begin{itemize}
            \item Two and a half;
            \item Almost three.
        \end{itemize}
        \item Three.
    \end{itemize}

%   \null\par                                            %quick and dirty solution
    \textbf{There should be a vertical spacing here.}
    This is a new paragraph.
    It should thus be preceded with parskip.
\end{document}

Answer 1

這幾乎不那麼骯髒，但它使用了提供的工具enumitem，玩弄after鑰匙：

\documentclass[parskip=half]{scrartcl}
\usepackage{enumitem}
\setlist{%
    topsep=-\parskip,
    partopsep=\parskip,
    noitemsep,
}

\begin{document}

This sentence is a paragraph on its own; there is thus a vertical parskip prior next paragraph.

Following list is \emph{within} a paragraph, with preceding and appended text.
\begin{itemize}
    \item One,
    \item Two,
    \begin{itemize}
        \item Two and a half;
        \item Almost three.
    \end{itemize}
    \item Three.
\end{itemize}
This text is appended to the previous list.
However, following list starts a new paragraph on its own.

\begin{enumerate}[after =\vspace*{-\partopsep}]
    \item Did you notice the vertical spacing preceding this list?
    \item Two,
    \begin{enumerate}
        \item Two and a half;
        \item Almost three.
    \end{enumerate}
    \item Three.
\end{enumerate}
\textbf{There shouldn't be a vertical spacing here.}
This text is appended to the previous list too.

And finally, a list with preceding text only.
\begin{itemize}[after = \vspace*{\partopsep}]
    \item One,
    \item Two,
    \begin{itemize}
        \item Two and a half;
        \item Almost three.
    \end{itemize}
    \item Three.
\end{itemize}


\textbf{There should be a vertical spacing here.}
This is a new paragraph.
It should thus be preceded with parskip.

\end{document} 

Answer 2

這是一個可能的解決方案，使用 lua 獲取原始程式碼中的下一行並檢查其是否為空。當然，它僅適用於 lualatex。它可能需要對準空行進行一些改進（只有空格？）。

\documentclass{article}

\usepackage{luacode}
\begin{luacode*}
function manageNextLine(s)
  luatexbase.remove_from_callback("process_input_buffer", "manageNextLine")
  if s == "" then
    return "\\leavevmode\\par"
  else
    return s
  end
end
\end{luacode*}

\parskip=10ex  % to see it better

\usepackage{enumitem}
\setlist{noitemsep,
         topsep=-\parskip,
         partopsep=\parskip,
         after=\luadirect{luatexbase.add_to_callback("process_input_buffer", manageNextLine , "manageNextLine")}
  }



\begin{document}
Para

Para2
\begin{itemize}
\item 1
\item 2
\end{itemize}
%
Continuing the same para.

Para3
\begin{itemize}
\item A.
\item B.
\end{itemize}

Suite with vertical spacing.

\end{document}