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为什么我的 \xdef 失败了？

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为什么我的 \xdef 失败了？

基于我所做的事情此主题，为什么我的作业没有做完\xdef？

练习页显示得很好。理想情况下，答案页看起来应该完全相同，当然，答案除外。

但答案页面却很乱。有时可以编译，有时不能。

如果我注释掉\AnswerList底部附近的代码，代码就可以完美运行。所以问题与此有关。

是什么赋予了？

这是代码。

\documentclass{article}

\usepackage[margin=2cm]{geometry}
\usepackage{ifthen}
\usepackage{pgf}
\usepackage{pgffor}
\usepackage{tikz}

\setlength{\parindent}{0pt} 

\pgfmathsetseed{\number\pdfrandomseed}

\newcommand{\InitVariables}
{
 \pgfmathsetmacro{\FactorA}{int(random(1,9))}
 \pgfmathsetmacro{\FactorB}{int(random(1,9))}
 \pgfmathsetmacro{\Product}{int(\FactorA*\FactorB)}
 \pgfmathsetmacro{\Structure}{int(random(0,2))}
}

\newcommand{\AnswerSpace}
{%
 \tikz[baseline=6pt]{\draw (0,0)rectangle(0.9,0.9);}
}

\newcommand{\ASF}[1] % Answer Space Filled
{%
 \tikz[baseline=6pt]{\draw (0,0)rectangle(0.9,0.9); \node[center] at (0.45,0.35) {\color{blue}#1};}
}

\newcommand{\OneEquation}
{%
 \large
 \InitVariables
 \ifcase\Structure\relax
  \def\Exercise{\(\FactorA \times \FactorB = \AnswerSpace\)}
  \def\Answer{\(\FactorA \times \FactorB =\ASF{\Product}\)}
  \or
  \def\Exercise{\(\FactorA \times \AnswerSpace = \Product\)}
  \def\Answer{{\(\FactorA \times \ASF{\FactorB} = \Product\)}}
  \or
  \def\Exercise{\(\AnswerSpace \times \FactorB = \Product\)}
  \def\Answer{\(\ASF{\FactorA} \times \FactorB = \Product\)}
 \fi
}

\newcommand{\AnswerList}{}

\newcommand{\ExerciseList}[1]
{%
 \foreach \x in {1,2,3,...,{#1}} 
 {%
  \OneEquation \Exercise \par \vspace{0.5cm}
   \xdef\AnswerList{\AnswerList \Answer \par \vspace{0.5cm}}
 }
}




\begin{document}

\section{Exercises}
\ExerciseList{10}

\pagebreak
\section{Answers}
\AnswerList

\end{document}

答案1

您不能在 xdef/edef 中放置任意 tex 命令，如果它们不能通过扩展起作用，它们将会失败，您不想完全扩展它，只需扩展数字部分，一步。

\documentclass{article}

\usepackage[margin=2cm]{geometry}
\usepackage{ifthen}
\usepackage{pgf}
\usepackage{pgffor}
\usepackage{tikz}

\setlength{\parindent}{0pt} 

\pgfmathsetseed{\number\pdfrandomseed}

\newcommand{\InitVariables}
{
 \pgfmathsetmacro{\FactorA}{int(random(1,9))}
 \pgfmathsetmacro{\FactorB}{int(random(1,9))}
 \pgfmathsetmacro{\Product}{int(\FactorA*\FactorB)}
 \pgfmathsetmacro{\Structure}{int(random(0,2))}
}

\newcommand{\AnswerSpace}
{%
 \tikz[baseline=6pt]{\draw (0,0)rectangle(0.9,0.9);}
}

\newcommand{\ASF}[1] % Answer Space Filled
{%
 \tikz[baseline=6pt]{\draw (0,0)rectangle(0.9,0.9); \node at (0.45,0.35) {\color{blue}#1};}
}

\newcommand{\OneEquation}
{%
 \large
 \InitVariables
 \ifcase\Structure\relax
  \def\Exercise{\(\FactorA \times \FactorB = \AnswerSpace\)}
  \edef\Answer{\noexpand\(\FactorA \times \FactorB =\noexpand\ASF{\Product}\noexpand\)}
  \or
  \def\Exercise{\(\FactorA \times \AnswerSpace = \Product\)}
  \edef\Answer{{\noexpand\(\FactorA \times\noexpand \ASF{\FactorB} = \Product\noexpand\)}}
  \or
  \def\Exercise{\(\AnswerSpace \times \FactorB = \Product\)}
  \edef\Answer{\noexpand\(\noexpand\ASF{\FactorA} \times \FactorB = \Product\noexpand\)}
 \fi
}

\newcommand{\AnswerList}{}

\makeatletter
\newcommand{\ExerciseList}[1]
{%
 \foreach \x in {1,2,3,...,{#1}} 
 {%
  \OneEquation \Exercise \par \vspace{0.5cm}
   \expandafter\g@addto@macro\expandafter\AnswerList\expandafter
           {\Answer \par \vspace{0.5cm}}
 }
}
\makeatother




\begin{document}

\section{Exercises}
\ExerciseList{10}

\pagebreak
\section{Answers}
\AnswerList

\end{document}

在此处输入图片描述

答案2

您正在使用\ASF：\xdef这是行不通的，因为\tikz不是可扩展的命令。它不是该上下文中唯一危险的宏。

这是使用 的不同实现expl3。有一些代码重复，但您可能希望对练习和解决方案使用不同的渲染，因此我定义了不同的函数来执行它们。

\documentclass[twocolumn]{article}

\usepackage[margin=2cm]{geometry}
\usepackage{tikz}
\usepackage{xparse}

\setlength{\parindent}{0pt} 

\pgfmathsetseed{\number\pdfrandomseed}

\NewDocumentCommand{\InitVariables}{}{%
  \pgfmathsetmacro{\FactorA}{int(random(1,9))}%
  \pgfmathsetmacro{\FactorB}{int(random(1,9))}%
  \pgfmathsetmacro{\Product}{int(\FactorA*\FactorB)}%
  \pgfmathsetmacro{\Structure}{int(random(0,2))}%
}

\NewDocumentCommand{\AnswerSpace}{}{%
  \tikz[baseline=6pt]{\draw (0,0)rectangle(0.9,0.9);}%
}

\NewDocumentCommand{\ASF}{m}{% Answer Space Filled
  \tikz[baseline=6pt]{%
    \draw (0,0)rectangle(0.9,0.9);
    \node[blue] at (0.45,0.35) {#1};
  }%
}

\ExplSyntaxOn
\NewDocumentCommand{\OneEquation}{}
 {
  \InitVariables
  \int_case:nn { \Structure }
   {
    {0}{
        \wcla_make_exercise:xxx {\FactorA}{\FactorB}{\AnswerSpace}
        \wcla_make_answer:xxx {\FactorA}{\FactorB}{\ASF{\Product}}
       }
    {1}{
        \wcla_make_exercise:xxx {\FactorA}{\AnswerSpace}{\Product}
        \wcla_make_answer:xxx {\FactorA}{\ASF{\FactorB}}{\Product}
       }
    {2}{
        \wcla_make_exercise:xxx {\AnswerSpace}{\FactorB}{\Product}
        \wcla_make_answer:xxx {\ASF{\FactorA}}{\FactorB}{\Product}
       }
   }
}

\seq_new:N \l_wcla_exercise_list_seq
\seq_new:N \l_wcla_answer_list_seq

\cs_new_protected:Nn \wcla_make_exercise:nnn
 {
  \seq_put_right:Nn \l_wcla_exercise_list_seq { \( #1 \times #2 = #3 \) }
 }
\cs_generate_variant:Nn \wcla_make_exercise:nnn { xxx }

\cs_new_protected:Nn \wcla_make_answer:nnn
 {
  \seq_put_right:Nn \l_wcla_answer_list_seq { \( #1 \times #2 = #3 \) }
 }
\cs_generate_variant:Nn \wcla_make_answer:nnn { xxx }

\NewDocumentCommand{\ExerciseList}{m}
 {
  \prg_replicate:nn { #1 } { \OneEquation }
  \seq_use:Nn \l_wcla_exercise_list_seq { \par \vspace{0.5cm} }
 }

\NewDocumentCommand{\PrintAnswers}{}
 {
  \seq_use:Nn \l_wcla_answer_list_seq { \par \vspace{0.5cm} }
 }
\ExplSyntaxOff

\begin{document}

\section{Exercises}
\ExerciseList{10}

\newpage

\section{Answers}
\PrintAnswers

\end{document}

我twocolumn只是为了把所有东西都放在同一张图片中，以便更好地检查。

最值得注意的是如何\wcla_make_exercise:xxx定义。首先我定义\wcla_make_exercise:nnn将公式添加到包含练习列表的序列中\(#1\times#2=#3\)。然后定义完全展开其三个参数的变体，这被称为，因此的值\FactorA和\FactorB是\Product当前的值。在这里完全展开没有问题\ASF，因为\NewDocumentCommand这使得它很健壮。

在此处输入图片描述

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