列表环境中 \ref 行的自定义数字样式

Question

考虑以下 MWE：

\documentclass{article}

\usepackage{tikz}

\usepackage{listings}

\lstset{%
  basicstyle =\ttfamily,
  language = Python,
  keywordstyle = \bfseries,
  commentstyle = \itshape,
  numbers = left,
  numberstyle = \tiny\sffamily,
  escapechar = |,
  gobble = 2,
}

\begin{document}

\begin{lstlisting}
  import numpy as np
  from matplotlib import pyplot as plt

  t = np.linspace(0, 1, 100) |\label{that-line}|
  plt.plot(t, t**2)
  plt.show() |\label{that-other-line}|
\end{lstlisting}

Please see line~\ref{that-line} and line~\ref{that-other-line}.

\end{document}

当前输出为：

我希望与被\ref'ed 的行（即我的 MWE 中的第 4 行和第 6 行）相对应的数字具有特定的样式（例如，排版在正方形或圆形内，理想情况下是任意tikz代码）。例如：

Answer 1

改编自我的回答如何将可引用的编号圆圈符号添加到代码列表中？：

\documentclass{article}

\usepackage{tikz}

\usepackage{listings}

\usepackage{circledsteps}
\pgfkeys{/csteps/outer color=orange}

\lstset{%
  basicstyle =\ttfamily,
  language = Python,
  keywordstyle = \bfseries,
  commentstyle = \itshape,
  numbers = left,
  numberstyle = \tiny\sffamily,
  escapechar = |,
  gobble = 2,
}
\makeatletter
\newcommand*\CircleNext{%
  \lst@AddToHook{OnNewLine}{%
   \def\thelstnumber{\Circled{\arabic{lstnumber}}\hskip-2.1pt}}%
}
\def\circlabel#1{
  \lst@AddToHook{OnNewLine}{%
   \def\thelstnumber{\arabic{lstnumber}}}%
  \label{#1}%
}
\makeatother
\begin{document}

\begin{lstlisting}
  import numpy as np
  from matplotlib import pyplot as plt
  |\CircleNext|
  t = np.linspace(0, 1, 100) |\circlabel{that-line}|
  plt.plot(t, t**2)|\CircleNext|
  plt.show() |\circlabel{that-other-line}|
\end{lstlisting}

Please see line~\ref{that-line} and line~\ref{that-other-line}.

\end{document}

---

下面是一个不需要\CircleNext命令的变体。它通过编写由格式组成的额外标签来工作listing number-line number。OnNewLine现在，命令\thelstnumber（打印每行的行号）被修改为检查当前列表和当前行的标签是否存在，而不是列表的钩子。如果标签存在，则数字会被圈出（在下一次运行时）。

不幸的\thelstnumber是 也被写入 .aux 文件作为标签文本，由 读取\ref。为了防止主文本中出现带圈的数字，一种解决方案是\thelstnumber在写入常规 时临时重新定义为数字\label。

其余代码用于记账，创建并增加新标签中使用的列表计数器。

代码：

\documentclass{article}
\usepackage{tikz}
\newcounter{lstprefix}
\setcounter{lstprefix}{0}
\usepackage{listings}
\AddToHook{env/lstlisting/before}{\stepcounter{lstprefix}}

\usepackage{circledsteps}
\pgfkeys{/csteps/outer color=orange}

\lstset{%
  basicstyle =\ttfamily,
  language = Python,
  keywordstyle = \bfseries,
  commentstyle = \itshape,
  numbers = left,
  numberstyle = \tiny\sffamily,
  escapechar = |,
  gobble = 2,
}
\makeatletter
\def\thelstnumber{%
\ifcsname r@lst\thelstprefix-\arabic{lstnumber}\endcsname%
\Circled{\arabic{lstnumber}}\hskip-2.1pt%
\else%
\arabic{lstnumber}%
\fi%
}
\def\circlabel#1{
  {\def\thelstnumber{\arabic{lstnumber}}\label{#1}}%
  \label{lst\thelstprefix-\arabic{lstnumber}}%
}
\makeatother
\begin{document}

\begin{lstlisting}
  import numpy as np
  from matplotlib import pyplot as plt
  
  t = np.linspace(0, 1, 100) |\circlabel{that-line}|
  plt.plot(t, t**2)
  plt.show() |\circlabel{that-other-line}|
\end{lstlisting}

Please see line~\ref{that-line} and line~\ref{that-other-line}.

\begin{lstlisting}
  import numpy as np
  from matplotlib import pyplot as plt |\circlabel{import-line}|
  
  t = np.linspace(0, 1, 100)
  plt.plot(t, t**2)
  plt.show()
\end{lstlisting}
See also line \ref{import-line}.
\end{document}

这将创建以下 .aux 文件：

\relax 
\newlabel{that-line}{{4}{1}}
\newlabel{lst1-4}{{\Circled {4}\hskip -2.1pt}{1}}
\newlabel{that-other-line}{{6}{1}}
\newlabel{lst1-6}{{\Circled {6}\hskip -2.1pt}{1}}
\newlabel{import-line}{{2}{1}}
\newlabel{lst2-2}{{\Circled {2}\hskip -2.1pt}{1}}
\gdef \@abspage@last{1}