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我真的必须手动初始化 xkeyval 的密钥吗？

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我真的必须手动初始化 xkeyval 的密钥吗？

如果我定义了一些（许多）键，xkeyval如果没有明确设置键，我是否真的必须初始化它们才能使用它们？

\documentclass{article}

\usepackage{xkeyval}

\makeatletter
\define@cmdkeys{fam}[my@]{%
   fonta,
   fontb,
   % ...
   % fontn
}[]

%\presetkeys{fam}{keya,keyb}{}

%\setkeys{fam}{
%   fonta,
%   fontb,
%   % ...
%   % fontn
%}


\newcommand{\mymacro}[2]{%
   {\my@fonta #1} and {\my@fontb #2}
}
\makeatother



\begin{document}
\mymacro{Font A}{Font B}
\end{document}

此代码将成为新包的一部分。我的许多键应设置字体，默认情况下该字体为空（ii 如果用户没有为其设置键值对）。我想在宏定义中使用这些字体，但我必须手动将所有字体初始化为空。由于这种行为，我需要在添加新字体时处理两个列表（\define@cmdkeys和）。\setkeys

据我理解，上述示例应该按原样编译，但我需要取消注释这些\setkeys行以初始化宏。

当然，有些键必须有预设值，而且我必须初始化它们。例如，我们将是一个预设的savemode布尔值，但如果用户设置了没有值的键，则应该默认为布尔值。falsetrue

额外的做什么\presetkeys？我不明白本节中的手册。最好将其作为新问题发布吗？

答案1

这键值不提供密钥的自动初始化。最好的选择是键盘阅读器和龙腾包；它们提供在定义键之后自动将键初始化为其默认值的命令。键盘阅读器包比龙腾包，但功能较少。下面是基于键盘阅读器（和键值） 包裹。

\documentclass{article}
\usepackage{keyreader}
\usepackage{xcolor}
\makeatletter
\newdimen\shadowsize
\define@boolkey[KV]{shadowbox}[shb@]{frame}[true]{}
\define@boolkey[KV]{shadowbox}[shb@]{shadow}[true]{}
\define@cmdkey[KV]{shadowbox}[shb@]{framecolor}[black]{}
\define@cmdkey[KV]{shadowbox}[shb@]{shadecolor}[white]{}
\define@cmdkey[KV]{shadowbox}[shb@]{shadowcolor}[gray]{}
\define@cmdkey[KV]{shadowbox}[shb@]{boxwidth}[2cm]{}
\define@choicekey+[KV]{shadowbox}{align}[\val\nr]
  {center,right,left,justified}[center]{%
  \ifcase\nr\relax
    \def\curralign##1{\hfil##1\hfil}%
  \or
    \def\curralign##1{\hfill##1}%
  \or
    \def\curralign##1{##1\hfill}%
  \or
    \let\curralign\@iden
  \fi
}{%
  \@latex@error{Erroneous value for a choice key}
    {Invalid value '#1' for key 'align' of family '\XKV@tfam'}%
}
% The following keys could have been defined as command keys, but this is
% just an illustration:
\define@key[KV]{shadowbox}{framesize}{\def\currfboxrule{#1}}
\define@key[KV]{shadowbox}{shadowsize}{\shadowsize=\dimexpr#1\relax}

% Save the values of the following keys when they are being set:
\savevaluekeys[KV]{shadowbox}{frame,framecolor,framesize}

% 'Presetting keys' means set the following keys whenever \setkeys is called.
% These keys should be set BEFORE the keys listed in the current argument of
% \setkeys are set, provided that these keys aren't listed in the current
% argument of \setkeys. If these keys appear in the current argument of \setkeys,
% then obviously the user has new values for them or he wants the keys to be
% set with their default values.

% The command \presetkeys of the xkeyval package expects both 'head' and 'tail'.
% The keyreader package splits \presetkeys into two, hopefully less confusing,
% commands: \krdpresetkeys and \krdpostsetkeys.

\krdpresetkeys[KV]{shadowbox}{%
  frame,framecolor=black,framesize=.8pt,boxwidth=2cm,align=center,
  shadecolor=gray!15
}
% 'Postsetting keys' means set the following keys whenever \setkeys is called.
% These keys should be set AFTER the keys listed in the current argument of
% \setkeys are set, provided that these keys aren't listed in the current
% argument of \setkeys:
\krdpostsetkeys[KV]{shadowbox}{%
  shadow=\usevalue{frame},shadowcolor=\usevalue{framecolor}!40,
  shadowsize=\dimexpr\usevalue{framesize}*5\relax
}
\newcommand*\newshadowbox[2][]{%
  \krdsetkeys[KV]{shadowbox}{#1}%
  \begingroup
  \ifshb@frame
    \fboxrule=\dimexpr\currfboxrule\relax
  \else
    \fboxrule=0pt
  \fi
  \ifshb@shadow\else\shadowsize=0pt \fi
  \sbox\z@{\fcolorbox{\shb@framecolor}{\shb@shadecolor}{%
    \hb@xt@\shb@boxwidth{\curralign{#2}}%
  }}%
  \hskip\shadowsize
  \color{\shb@shadowcolor}%
  \rule[-\dp0]{\wd0}{\dimexpr\ht0+\dp0\relax}%
  \llap{\raisebox{\shadowsize}{\box0\hskip\shadowsize}}%
  \endgroup
}
\makeatother

\begin{document}
\noindent
\newshadowbox{tobi1}
\newshadowbox[framecolor=gray,shadecolor=blue!25,shadowsize=10pt,align=left]{tobi2}
\newshadowbox[shadow=false,boxwidth=1cm]{tobi3}
\newshadowbox[framesize=2pt,framecolor=red,shadowcolor=green]{tobi4}
\newshadowbox[frame=false,shadow,shadowsize=9pt,shadowcolor=violet!50,align=right]{tobi5}
\end{document}


% Using a feature of the keyreader package, all the above keys can be defined 
% compactly as follows. The command \krddefinekeys will automatically initialize
% the keys after they have been defined.
\krddefinekeys*[KV]{shadowbox}[shb@]{%
  bool/frame/true;
  bool/shadow/true;
  cmd/framecolor/black;
  cmd/shadecolor/white;
  cmd/shadowcolor/gray;
  cmd/boxwidth/2cm;
  ord/framesize/.5pt/\def\currfboxrule{#1};
  ord/shadowsize/2pt/\shadowsize=\dimexpr#1\relax;
  choice/align/center/
    center.do=\def\curralign##1{\hfil##1\hfil},
    right.do=\def\curralign##1{\hfill##1},
    left.do=\def\curralign##1{##1\hfill},
    justified.do=\let\curralign\@iden;
}

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