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将参数添加到现有命令会产生错误

tag-icon • tag-icon macros environments optional-arguments
将参数添加到现有命令会产生错误

我的教授给我的模板中有这个命令

\newcommand{\homeworkProblemName}{}%
\newcounter{homeworkProblemCounter}%
\newenvironment{homeworkProblem}[1][Problem \arabic{homeworkProblemCounter} - Homework]%
  {\stepcounter{homeworkProblemCounter}%
   \renewcommand{\homeworkProblemName}{#1}%
   \section{\homeworkProblemName}%
   \enterProblemHeader{\homeworkProblemName}}%
  {\exitProblemHeader{\homeworkProblemName}}%

我想在第三行添加第二个参数，以便能够有类似的内容，Problem 1 - Homework 1但家庭作业的数量可以改变，例如，我可以有Problem 1 - HW 1然后Problem 4 - HW 2等等Problem 2 - HW 3。

我试过这个

\newcommand{\homeworkProblemName}{}%
\newcounter{homeworkProblemCounter}%
\newenvironment{homeworkProblem}[2][Problem \arabic{homeworkProblemCounter} - Homework #2]%
  {\stepcounter{homeworkProblemCounter}%
   \renewcommand{\homeworkProblemName}{#1}%
   \section{\homeworkProblemName}%
   \enterProblemHeader{\homeworkProblemName}}%
  {\exitProblemHeader{\homeworkProblemName}}%

但我收到编译错误

`Illegal parameter number in definition of \homeworkProblem. <to be read again> 2`
`{\exitProblemHeader{\homeworkProblemName}}`

我没有创建命令和所有这些东西的经验，我只是一个基本的 LaTeX 用户。

有人能告诉我怎样做这个吗？

更新

这里有用的是 exitProblemHeader 和 enterProblemHeader 的定义

\newcommand{\enterProblemHeader}[1]{\nobreak\extramarks{#1}{#1 continued on next page\ldots}\nobreak%
                                    \nobreak\extramarks{#1 (continued)}{#1 continued on next page\ldots}\nobreak}%
\newcommand{\exitProblemHeader}[1]{\nobreak\extramarks{#1 (continued)}{#1 continued on next page\ldots}\nobreak%
                                   \nobreak\extramarks{#1}{}\nobreak}%

答案1

环境定义中的第二个方括号指定第一个参数的默认值（从而使其成为可选的）。不可能在其中引用其他参数（您试图引用第二个参数）。

我建议定义命令\homeworkNumber（无论如何它对于所有问题都是相同的）并在定义中使用它：

\newcommand{\homeworkName}{42}%
\newenvironment{homeworkProblem}[1][Problem \arabic{homeworkProblemCounter} - Homework \homeworkName]
{...}{...}

答案2

我的印象是，最初的定义是有缺陷的，homeworkProblem环境绝不使用可选参数调用。

\newcommand{\homeworkProblemName}{}
\newcounter{homeworkProblemCounter}
\newenvironment{homeworkProblem}[1][Problem \arabic{homeworkProblemCounter} - Homework]
  {\stepcounter{homeworkProblemCounter}
   \renewcommand{\homeworkProblemName}{#1}%
   \section{\homeworkProblemName}%
   \enterProblemHeader{\homeworkProblemName}}
  {\exitProblemHeader{\homeworkProblemName}}

呼唤

\begin{homeworkProblem}[Problem \arabic{homeworkProblemCounter} - Foo]

仅仅改变最后一个词似乎很笨拙；调用

\begin{homeworkProblem}[Problem]

不会产生任何数字，但计数器仍会增加。

如果文档中从未使用环境和可选参数，则只需将其更改为接受对您有意义的参数：

\newcommand{\homeworkProblemName}{}
\newcounter{homeworkProblemCounter}
\newenvironment{homeworkProblem}[1][]
  {\stepcounter{homeworkProblemCounter}
   \renewcommand{\homeworkProblemName}{%
     Problem \arabic{homeworkProblemCounter} - Homework\addNumber{#1}}%
   \section{\homeworkProblemName}%
   \enterProblemHeader{\homeworkProblemName}}
  {\exitProblemHeader{\homeworkProblemName}}

\newcommand{\addNumber}[1]{\if\relax\detokenize{#1}\relax\else\space#1\fi}

因此

\begin{homeworkProblem}

将给出原始行为，而

\begin{homeworkProblem}[4]

将执行“问题 3 - 家庭作业 4”（如果 3 是当前问题编号）。

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