problem with cleveref

Question

I would like to colorize my theorems and questions. I use the following code:

\documentclass{amsart}
\usepackage[dvipsnames]{xcolor}
\usepackage[breaklinks,colorlinks,pagebackref]{hyperref} 
\hypersetup{linkcolor=Red , citecolor=Green}
\usepackage[capitalise,nameinlink]{cleveref}
\newtheorem{theorem}{\color{Blue} Theorem}[section]
\theoremstyle{definition}
\newtheorem{question}[theorem]{\color{Blue} Question }
\begin{document}
\begin{question}\label{qu1}  Question 1
\end{question}

\begin{theorem}\label{thm1} Theorem 1
\end{theorem}
Now we reference to ~\cref{thm1} and ~\cref{qu1}.

\end{document}

By running this, I get the following Error massage:

Argument of \@declaredcolor has an extra }."

I don't know what the problem is. Can you see the problem?

Thanks

Please advise whether the color Blue should apply to just the environment's "label" ("Theorem", "Question", etc) or to the associated numbers ("0.1", "0.2", etc) as well. — Mico, Apr 18 '18 at 01:06

egreg · Answer 1 · 2018-04-18T06:55:02.650

You have to remove the color specification for \cref:

\documentclass{amsart}
\usepackage[dvipsnames]{xcolor}
\usepackage[colorlinks,pagebackref]{hyperref} 
\usepackage[capitalise,nameinlink]{cleveref}

\hypersetup{linkcolor=Red , citecolor=Green}

\newtheorem{theorem}{\textcolor{Blue}{Theorem}}[section]
\theoremstyle{definition}
\newtheorem{question}[theorem]{\textcolor{Blue}{Question}}

\crefname{theorem}{Theorem}{Theorems}
\crefname{question}{Question}{Questions}

\begin{document}

\begin{question}\label{qu1}
Question 1
\end{question}

\begin{theorem}\label{thm1}
Theorem 1
\end{theorem}

Now we reference to~\cref{thm1} and~\cref{qu1}.

\end{document}

OK, this doesn't color the number. Since Mico stole my code, here's a better one.

\documentclass{amsart}
\usepackage[dvipsnames]{xcolor}
\usepackage[colorlinks,pagebackref]{hyperref} 
\usepackage[capitalise,nameinlink]{cleveref}

\hypersetup{linkcolor=Red , citecolor=Green}

% see https://tex.stackexchange.com/a/17555/4427
\newtheoremstyle{colorplain}
  {\topsep}   % ABOVESPACE
  {\topsep}   % BELOWSPACE
  {\itshape}  % BODYFONT
  {0pt}       % INDENT (empty value is the same as 0pt)
  {\color{Blue}\bfseries} % HEADFONT
  {.}         % HEADPUNCT
  {5pt plus 1pt minus 1pt} % HEADSPACE
  {}          % CUSTOM-HEAD-SPEC
\newtheoremstyle{colordefinition}
  {\topsep}   % ABOVESPACE
  {\topsep}   % BELOWSPACE
  {\normalfont}  % BODYFONT
  {0pt}       % INDENT (empty value is the same as 0pt)
  {\color{Blue}\bfseries} % HEADFONT
  {.}         % HEADPUNCT
  {5pt plus 1pt minus 1pt} % HEADSPACE
  {}          % CUSTOM-HEAD-SPEC

\theoremstyle{colorplain}
\newtheorem{theorem}{Theorem}[section]
\theoremstyle{colordefinition}
\newtheorem{question}[theorem]{Question}

\begin{document}

\begin{question}\label{qu1}
Question 1
\end{question}

\begin{theorem}\label{thm1}
Theorem 1
\end{theorem}

Now we reference to~\cref{thm1} and~\cref{qu1}.

\end{document}

Now I am very fast to upvote also for you :-). – Sebastiano Apr 17 '18 at 22:44 — Sebastiano, Apr 17 '18 at 22:44

Mico · Accepted Answer · 2018-04-18T05:41:29.220

3

\color is a "fragile" (in the LaTeX-specific sense of the word) command. You need to change

\newtheorem{theorem}{\color{Blue} Theorem}[section]
\theoremstyle{definition}
\newtheorem{question}[theorem]{\color{Blue} Question }

to

\newtheorem{theorem}{\protect\color{Blue} Theorem}[section]
\theoremstyle{definition}
\newtheorem{question}[theorem]{\protect\color{Blue} Question }

Even better though, as shown in egreg's answer, is to (re)run \crefname on the theorem and question counters. Here's an MWE (minimum working example):

\documentclass{amsart} % loads 'amsthm' package automatically

\usepackage[dvipsnames]{xcolor}
\usepackage[colorlinks,linkcolor=Red]{hyperref} 
\usepackage[capitalise,nameinlink]{cleveref}

\newtheorem{theorem}{\color{Blue}Theorem}[section]
\theoremstyle{definition}
\newtheorem{question}[theorem]{\color{Blue}Question}
\crefname{theorem}{Theorem}{Theorems} % thanks, @egreg!
\crefname{question}{Question}{Questions}

\begin{document}
\setcounter{section}{2} % just for this example

\begin{question}\label{qu1}Question 1\end{question}
\begin{theorem}\label{thm1}Theorem 1\end{theorem}
\noindent
Now we cross-reference~\cref{thm1,qu1}.
\end{document}

edited Apr 18 '18 at 05:41

answered Apr 17 '18 at 22:03

Mico

506,678

1

@MOB Mico is very excellent user. He will surely solve your problem. – Sebastiano Apr 17 '18 at 22:20
Dear @Mico: Thanks for you answer. I have added \protect. But when I run it the Question will be in Blue and the link to it is also in Blue. But the linkcolor=Red is not Blue. Can you see the problem? – MO B Apr 17 '18 at 22:23
Yes, it compiles fine, but doesn't do what's expected. Besides, \textcolor is the right command instead of \color. – egreg Apr 17 '18 at 22:45
@egreg - with \textcolor, only the "label" ("Theorem", "Question", etc) gets colorized, but not the associated number. That's why I kept the OP's \color directive (while adding \protect). However, your solution (run \crefname) does away with the need for \protection. – Mico Apr 18 '18 at 05:35
@MOB - I've updated my answer. – Mico Apr 18 '18 at 05:42
Dear @Mico: Thank you very much. It works now. – MO B Apr 18 '18 at 08:31

problem with cleveref

2 Answers2