The memoir class - The UK TeX Archive

15.4. Files{\par\endwriteverbatim\end@nswer\@esphack}\fi % end of \ifdraftdoc ...\else ...When I was testing this code I had a surprise as I got nasty error messages from LaTeXthe first time around, but it worked fine when I processed the source a second time! Theproblem lies in the code line\addtostream{ansout}{\par\noindent\textbf{Answer \ref{#1}:}}%The first time around, LaTeX processed the \ref command and of course it was undefined.In this case \ref gets replaced by the code to print the error message, whichinvolves macros that have @ in their names, which LaTeX only understands under specialcircumstances. The second time around \ref gets replaced by the question number andall is well. I then remembered that some commands need protecting when they are writtenout, so I tried (I’ve wrapped the line to fit)\addtostream{ansout}{\par\noindent\protect\makeatletter\textbf{Answer\protect\ref{#1}:}\protect\makeatother}%which did work but seemed very clumsy.I then took another line of attack, and looked at the definition of \ref to see if I couldcome up with something that didn’t expand into @ names. The result of this was\addtostream{ansout}{\par\noindent\textbf{Answer\quietref{#1}:}}%In the kernel file ltxref.dtx I found the definition of \ref and it used a macro \@setref(shown below) to do its work. My \quietref locally changes the definition of \@setrefand then calls \ref, which will then use the modified \@setref.\def\@setref#1#2#3{% %% kernel definition\ifx#1\relax\protect\G@refundefinedtrue\nfss@text{\reset@font\bfseries ??}%\@latex@warning{Reference ‘#3’ on page \thepage \spaceundefined}%\else\expandafter#2#1\null\fi}\DeclareRobustCommand{\quietref}[1]{\begingroup\def\@setref##1##2##3{%\ifx##1\relax ??\else\expandafter##2##1\null\fi\ref{#1}\endgroup}Having gone all round the houses, the simplest solution was actually one that I hadskipped over\addtostream{ansout}{\par\noindent\textbf{Answer\protect\ref{#1}:}}%293