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ProcessPgfPackageOptions 之前和之后的初始样式定义？

tag-icon • tag-icon tikz-pgf pgfkeys package-writing package-options pgfopts
ProcessPgfPackageOptions 之前和之后的初始样式定义？

以下精彩文章对有关管理包选项的问题提供了以下答案：https://tex.stackexchange.com/a/707285/17200

\begin{filecontents*}[overwrite]{mypackage.sty}
% Preamble
\NeedsTeXFormat{LaTeX2e}[1994/06/01]
\ProvidesPackage{mypackage}[2024/01/01 MyPackage]

% Dependencies
\RequirePackage{pgfopts}
\RequirePackage{xparse}
\RequirePackage{xcolor}

\pgfkeys{/mypackage/.is family}
\def\mypackage@set#1{\pgfkeys{/mypackage,#1}}

\mypackage@set{
  % storage
  first-color/.store in=\mypackage@firstcolor,
  second-color/.store in=\mypackage@secondcolor,
  % default value
  first-color=blue,
  second-color=red,
  mypackage@init/.style/.expanded={ % HERE
    first-color=\mypackage@firstcolor,
    second-color=\mypackage@secondcolor
  }
}

\ProcessPgfPackageOptions{/mypackage}

\mypackage@set{
  mypackage@init/.style/.expanded={ % HERE
    first-color=\mypackage@firstcolor,
    second-color=\mypackage@secondcolor
  }
}

\NewDocumentCommand\newcolortheme{mm}{\mypackage@set{#1/.style={#2}}}

\NewDocumentCommand\printcolors{O{}}{%
  \bgroup%
  \mypackage@set{#1}%
  \mypackage@firstcolor{} and \mypackage@secondcolor{}\par%
  \egroup
}

\NewDocumentCommand\setcolors{m}{\mypackage@set{#1}}

\NewDocumentCommand\resetcolors{}{\mypackage@set{mypackage@init}}
\end{filecontents*}


\documentclass[preview=true,varwidth=true]{standalone}

\usepackage[first-color=green, second-color=yellow]{mypackage}

\newcolortheme{my theme}{first-color=brown, second-color=cyan}
% \setcolors{my theme/.style={first-color=brown, second-color=cyan}}

\begin{document}
\printcolors                      % Will print green and yellow
\printcolors[second-color=blue]   % Will print green and blue
\printcolors                      % Will print green and yellow

\setcolors{second-color=black}
\printcolors                      % Will print green and black
\printcolors[first-color=purple]  % Will print purple and black
\printcolors                      % Will print green and black

\setcolors{first-color=red}
\printcolors                      % Will print red and black

\setcolors{first-color=orange, second-color=pink}
\printcolors                      % Will print orange and pink

\resetcolors
\printcolors                      % Will print green and yellow
\printcolors[my theme]            % Will print brown and cyan
\printcolors                      % Will print green and yellow

\setcolors{my theme}
\printcolors                      % Will print brown and cyan      
\end{document}

问题：我想知道为什么mypackage@init需要出现在之前和之后\ProcessPgfPackageOptions{/mypackage}（在我注释的位置HERE）？

附加问题：expanded这是什么意思mypackage@init/.style/.expanded/实现了什么？

答案1

第一个标记的位置不执行任何操作，除非有人使用包选项内的HERE键（虽然我猜这不是有意的），只有第二个位置才是严格必要的，以设置颜色的默认值。mypackage@init

-handler.expanded会pgfkeys在将值传递给上面的键路径之前完全展开该值，因此 -handler.style看不到宏\mypackage@firstcolor或\mypackage@secondcolor，而只能看到宏中存储的内容（因此在默认情况下是blue和red）。这样，无论何时mypackage@init使用，颜色都会重置为加载包时有效的颜色。（如果省略了，.expanded宏\mypackage@firstcolor和\mypackage@secondcolor将根据自身进行设置，因此\def\mypackage@firstcolor{\mypackage@firstcolor}无论何时使用，都会建立一个无限循环）。

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