uline wraps failure and use Chinese characters produce Too many }'s

Question

encountered a very strange problem, using Chinese characters would produce Too many} 's errors.

\documentclass{article}
\usepackage{ctex}
\usepackage{ulem}

\newif\ifanswer
\newlength{\keylength}
\newcommand{\answer}[1]{%
    \ifanswer
    \uline{#1}%
    \else
    \settowidth{\keylength}{#1}
    \uline{\hspace{\keylength}}
    \fi}


\begin{document}

What do you think ? I think \uline{You are Good,You are Good,You are Good,You are Good,You are Good,You are Good}.  We are Good.
\\

\answertrue
What do you think ? I think \answer{You are Good,You are Good,You are Good,You are Good,You are Good,You are Good}. We are Good.
\\

\answerfalse
What do you think ? I think \answer{You are Good,You are Good,You are Good,You are Good,You are Good,You are Good}. We are Good.
\\

\answertrue
What do you think ? I think \answer{天地人}. We are Good.
\\

\answerfalse
What do you think ? I think \answer{天地人}. We are Good.
\\

\answertrue
What do you think ? I think \answer{$ 2+2=2^{2} $}. We are Good.
\\

\answerfalse
What do you think ? I think \answer{$ 2+2=2^{2} $}. We are Good.
\\



What do you think ? I think \uline{天地人 $ 2+2=2^{2} $}. We are Good.
\\

\answerfalse
What do you think ? I think \answer{天地人$ 2+2=2^{2} $}. We are Good.
\\

\answertrue
What do you think ? I think \answer{天地人$ 2+2=2^{2} $}. We are Good.


\end{document}

and，uline wraps failure.

Why not use \if ... \else environment ？

thanks！

You have to use answer inside math mode. Otherwise, uline stops working — , Jan 12 '20 at 09:18
I find problem， The error is due to the lack of space between the Chinese character and the $ character, but why does the lack of a space produce an error? — user140272, Jan 14 '20 at 12:53
\uline{\hspace{\keylength}} wraps the same way that \hspace{\keylength} does. — Donald Arseneau, Jun 13 '20 at 00:05
See the question: https://tex.stackexchange.com/questions/509209/uline-from-ulem-package-wont-break-lines-automatically-when-containing-boo — Donald Arseneau, Jun 13 '20 at 00:06

Davislor · Answer 1 · 2020-06-13T00:45:56.913

I cannot reproduce your bug on TeX Live 2020, but here is a new version of \answer that correctly wraps lines when you select \answerfalse. Because it uses linegoal, it requires XeLaTeX and might need to be compiled twice to resolve all references. See this question for several alternatives. Or @egreg’s answer here (which I hadn’t seen when I wrote this).

%% This MWE requires XeLaTeX.
\documentclass{article}
\usepackage{ctex}
\usepackage{ulem}
\usepackage{parskip} % You seemed to be trying to get this style with \.
\usepackage{ifthen, linegoal}
\newif\ifanswer
\newlength{\keylength}
\newlength{\chunklength}
\newcommand{\answer}[1]{%
    \ifanswer%
      \uline{#1}%
    \else%
      \settowidth{\keylength}{#1}%
      \setlength{\chunklength}{\linegoal}%
      \ifthenelse{\lengthtest{\chunklength<\keylength}}
        {\underline{\hspace{\chunklength}}\newline%
         \addtolength{\keylength}{-\chunklength}%
         \whiledo{\lengthtest{\keylength>\linewidth}}%
                 {\underline{\hspace{\linewidth}}\newline%
                  \addtolength{\keylength}{-\linewidth}}%
         \ifdim\keylength>0pt%
           \underline{\hspace{\keylength}}%
         \fi%
        }
        {\underline{\hspace{\keylength}}}%
    \fi}
\begin{document}
What do you think ? I think \uline{You are Good,You are Good,You are Good,You are Good,You are Good,You are Good}.  We are Good.
\answertrue
What do you think ? I think \answer{You are Good,You are Good,You are Good,You are Good,You are Good,You are Good}. We are Good.
\answerfalse
What do you think ? I think \answer{You are Good,You are Good,You are Good,You are Good,You are Good,You are Good}. We are Good.
\answertrue
What do you think ? I think \answer{天地人}. We are Good.
\answerfalse
What do you think ? I think \answer{天地人}. We are Good.
\answertrue
What do you think ? I think \answer{$ 2+2=2^{2} $}. We are Good.
\answerfalse
What do you think ? I think \answer{$ 2+2=2^{2} $}. We are Good.
What do you think ? I think \uline{天地人 $ 2+2=2^{2} $}. We are Good.
\answerfalse
What do you think ? I think \answer{天地人$ 2+2=2^{2} $}. We are Good.
\answertrue
What do you think ? I think \answer{天地人$ 2+2=2^{2} $}. We are Good.
\clearpage
\answerfalse
Lorem ipsum dolor sit amet, \answer{consectetur adipiscing elit. Nulla
tincidunt nec velit non convallis. Aliquam lectus erat, consectetur vel quam
eget, aliquam vehicula mauris. Nam aliquet, erat nec placerat pulvinar, tellus
est accumsan augue, eget aliquam ligula ligula id nunc. Integer in imperdiet
arcu. Pellentesque venenatis commodo blandit. Aenean scelerisque, erat quis
auctor dapibus, elit sapien tincidunt purus, id varius felis ipsum sed nulla.
Nullam semper est ut fringilla blandit. Aliquam viverra, libero sodales porta
dictum, felis urna egestas eros, ac posuere dui tellus et arcu. Nullam
vulputate, ligula non placerat mattis, erat tellus tempus ligula, eu commodo
risus lectus ut enim. Donec vitae ante sit amet purus rhoncus vestibulum non at
turpis. Suspendisse aliquam tellus vitae erat condimentum, sit amet maximus
tellus ullamcorper. Cras tincidunt, eros vel pharetra eleifend, neque orci
pharetra dui, sit amet dictum risus leo eget neque. Duis varius ligula in dui
posuere, in sollicitudin metus pellentesque. Nulla tellus sapien, lacinia nec
nisl sed, luctus volutpat felis}. Class aptent taciti sociosqu ad litora
torquent per conubia nostra, per inceptos himenaeos.
\answertrue
Lorem ipsum dolor sit amet, \answer{consectetur adipiscing elit. Nulla
tincidunt nec velit non convallis. Aliquam lectus erat, consectetur vel quam
eget, aliquam vehicula mauris. Nam aliquet, erat nec placerat pulvinar, tellus
est accumsan augue, eget aliquam ligula ligula id nunc. Integer in imperdiet
arcu. Pellentesque venenatis commodo blandit. Aenean scelerisque, erat quis
auctor dapibus, elit sapien tincidunt purus, id varius felis ipsum sed nulla.
Nullam semper est ut fringilla blandit. Aliquam viverra, libero sodales porta
dictum, felis urna egestas eros, ac posuere dui tellus et arcu. Nullam
vulputate, ligula non placerat mattis, erat tellus tempus ligula, eu commodo
risus lectus ut enim. Donec vitae ante sit amet purus rhoncus vestibulum non at
turpis. Suspendisse aliquam tellus vitae erat condimentum, sit amet maximus
tellus ullamcorper. Cras tincidunt, eros vel pharetra eleifend, neque orci
pharetra dui, sit amet dictum risus leo eget neque. Duis varius ligula in dui
posuere, in sollicitudin metus pellentesque. Nulla tellus sapien, lacinia nec
nisl sed, luctus volutpat felis}. Class aptent taciti sociosqu ad litora
torquent per conubia nostra, per inceptos himenaeos.
\end{document}

uline wraps failure and use Chinese characters produce Too many }'s

1 Answers1