在另一个宏中使用时有不同的宏行为

Question

请考虑以下 MWE：

\documentclass{article}

\newcommand{\mymargin}{\hspace*{3em}}
\newcommand{\innerbox}[1]{\mymargin\fbox{#1}\mymargin}
\newcommand{\outerbox}[1]{\fbox{#1}}

\begin{document}

test \innerbox{Hello} test% OK

test \outerbox{\innerbox{Hello} test \innerbox{Hello} test \innerbox{Hello}}%   I don't want space at beginning and end of box

test \outerbox{\fbox{Hello}\mymargin{} test \innerbox{Hello} test \mymargin\fbox{Hello}}%   what i'd like

\end{document}

（实际上，盒子的定义更加复杂，但我认为这不会改变任何逻辑）

我希望使用\innerboxinside\outerbox不会在框的开始和结束处产生空格。

我想我应该扩展参数#1（一旦去掉了不必要的空格）\outerbox并检测第一个和最后一个标记是否相等\mymargin，然后进行必要的更改，但我真的不知道该怎么做。有什么想法吗？

Answer 1

您可以检查（忽略空格）的参数中的第一个标记是否\outerbox是\innerbox，在这种情况下，插入一个负空格进行补偿。

最后，您可以递归地删除所有粘合节点。

\documentclass{article}

\newcommand{\mymarginwidth}{3em}
\newcommand{\mymargin}{\hspace*{\mymarginwidth}}
\newcommand{\negmymargin}{\hspace*{-\mymarginwidth}}

\newcommand{\innerbox}[1]{\mymargin\fbox{#1}\mymargin}
\makeatletter
\newcommand{\outerbox}[1]{%
  \fbox{%
    \@ifnextchar\innerbox{\negmymargin}{}#1%
    \forever@unskip
  }%
}
\newcommand{\forever@unskip}{%
  \ifnum\lastnodetype=11
    \expandafter\unskip\expandafter\forever@unskip
  \fi
}
\makeatother

\begin{document}

test \innerbox{Hello} test

test \outerbox{\innerbox{Hello} test \innerbox{Hello} test \innerbox{Hello}}

test \outerbox{\fbox{Hello}\mymargin{} test \innerbox{Hello} test \mymargin\fbox{Hello}}

test \outerbox{test \innerbox{Hello} test \innerbox{Hello}}

test \outerbox{\innerbox{Hello} test \innerbox{Hello} test}

test \outerbox{ test \innerbox{Hello} test \innerbox{Hello} }

test \outerbox{ \innerbox{Hello} test \innerbox{Hello} test }

\end{document}

Answer 2

此版本省略了位于任何水平盒子中的空格\innerbox，而不仅仅是\outerbox

\documentclass{article}

\newcommand{\mymargin}{\hspace*{3em}}
\newcommand{\innerbox}[1]{\ifhmode\ifinner\else\mymargin\fi\fi\fbox{#1}\ifhmode\ifinner\else\mymargin\fi\fi}
\newcommand{\outerbox}[1]{\fbox{#1}}

\begin{document}

test \innerbox{Hello} test% OK

test \outerbox{\innerbox{Hello} test \innerbox{Hello} test \innerbox{Hello}}%   I don't want space at beginning and end of box

test \outerbox{\fbox{Hello}\mymargin{} test \innerbox{Hello} test \mymargin\fbox{Hello}}%   what i'd like

\end{document}

egreg 指出，你可能不是你想要的样子，所以......

\documentclass{article}

\newcommand{\mymargin}{\hspace*{3em}}
\newcommand{\innerbox}[1]{\ifhmode\ifnum\lastpenalty=-1\else\mymargin\fi\fi\fbox{#1}\mymargin}
\newcommand{\outerbox}[1]{\fbox{\penalty-1#1\unskip\unskip}}

\begin{document}

test \innerbox{Hello} test% OK

test \outerbox{\innerbox{Hello} test \innerbox{Hello} test \innerbox{Hello}}%   I don't want space at beginning and end of box

test \outerbox{\fbox{Hello}\mymargin{} test \innerbox{Hello} test \mymargin\fbox{Hello}}%   what i'd like

\end{document}