todonotes and verbatim

Question

I want to put some comments about actual code into my document, and for that I thought I'd use \verb or \begin{verbatim}, but it turns out that the todonotes package does not like that:

\documentclass{minimal}

\usepackage{todonotes}

\begin{document}

\todo{\verb|Hello!|}

\end{document}

Which in turn gives the beautiful error:

! Argument of \reserved@a has an extra }.
<inserted text> 
                \par 
l.7 \todo{\verb|Hello!|}

A similar problem applies to \begin{verbatim}.

So... how do I get verbatim text/code into my todo notes?

Answer 1

Here's a way:

\documentclass{article}
\usepackage{todonotes}
\usepackage{xparse}
\newcounter{verbtodo}
\renewcommand{\theverbtodo}{\roman{verbtodo}}
\makeatletter
\NewDocumentCommand{\verbtodo}{v}{%
  \stepcounter{verbtodo}%
  \global\@namedef{verbtodo@\theverbtodo}{#1}%
  \todo{\texttt{\expandafter\protect\csname verbtodo@\theverbtodo\endcsname}}%
}
\makeatother

\begin{document}
\verbtodo|Hello${okp}^&|

\listoftodos

\end{document}

Limitation: the \listoftodos command must go at the end of the document. It shouldn't be a big deal.

---

The following more complicated version allows for having \listoftodos also at the start.

\documentclass{article}
\usepackage{todonotes}
\usepackage{xparse}
\newcounter{verbtodo}
\renewcommand{\theverbtodo}{\roman{verbtodo}}
\makeatletter
\NewDocumentCommand{\verbtodo}{v}{%
  \refstepcounter{verbtodo}\label{verbtodo@\theverbtodo}%
  \global\@namedef{verbtodo@\theverbtodo}{#1}%
  \addtocontents{tdo}{\defineverbtodo{\theverbtodo}|#1|}%
  \todo{\texttt{\expandafter\protect\csname verbtodo@\theverbtodo\endcsname}}%
}
\NewDocumentCommand{\defineverbtodo}{mv}{%
  \@namedef{verbtodo@#1}{#2}}
\makeatother

\begin{document}
\listoftodos
\verbtodo|Hello${okp}^&|


\end{document}

---

Limitations Braces must be balanced and % is not allowed.