我定义了以下两个新命令：
\usepackage{tcolorbox}
\newcommand{\mycommand}[1]{
\begin{tcolorbox}[
center, colback=black!20!white,
width=.75\textwidth, boxrule=0pt, frame empty]
#1
\end{tcolorbox}
}
\newcommand{\othercommand}[1]{
\begin{tcolorbox}[
width=.75\textwidth, boxrule=0pt, frame empty]
#1
\end{tcolorbox}
}
如您所见，除了第一个命令传递了参数center之外，这两个命令几乎完全相同colback。有没有办法将这两个命令概括为一个可以接受额外参数的命令，并且根据调用时是否存在该参数来呈现任一结果？
答案1
您可以利用适用于同一组级别的\tcbset所有es 的事实。tcolorbox
\documentclass{article}
\usepackage{tcolorbox}
\NewDocumentCommand{\mycommand}{sm}{%
\begingroup
\IfBooleanT{#1}{\tcbset{center,colback=black!20!white}}%
\begin{tcolorbox}[
width=.75\textwidth,
boxrule=0pt,
frame empty
]
#2
\end{tcolorbox}%
\endgroup
}
\begin{document}
\noindent X\dotfill X
\mycommand{
something something something something
something something something something
something something something something
}
\mycommand*{
something something something something
something something something something
something something something something
}
\mycommand{
something something something something
something something something something
something something something something
}
\end{document}
*-变体应用center和colback。
答案2
egreg 答案的一个变体，它考虑到可选参数的方括号在未限定的参数中出现时不需要匹配：
\documentclass{article}
\usepackage{tcolorbox}
\NewDocumentCommand{\mycommand}{sm}{%
\IfBooleanTF{#1}{\begin{tcolorbox}[center, colback=black!20!white, }%
{\begin{tcolorbox}[}%
width=.75\textwidth, boxrule=0pt, frame empty]%
#2%
\end{tcolorbox}%
}%
\begin{document}
\noindent X\dotfill X
\mycommand{
something something something something
something something something something
something something something something
}
\mycommand*{
something something something something
something something something something
something something something something
}
\mycommand{
something something something something
something something something something
something something something something
}
\end{document}
