Save command result in other command

Question

I am getting a value by a command. Now I am temporarily changing a saved variable which changes the command output. After I finished some code I want to reset the stored value if the value before the temporare code was 1.

My example can be stripped down to:

\newcommand{\storedvalue}{1}
\newcommand{\getstoredvalue}{\storedvalue}
\newcommand{\resetstoredvalue}{Resetting}

Some text

\let\oldvalue\protect\getstoredvalue
\renewcommand{\storedvalue}{0}

Some text which needs the stored value to be changed

\ifnum\numexpr\oldvalue>0%
    \resetstoredvalue{}%
\fi%

Of course the \getstoredvalue and the \resetstoredvalue are a lot more complicated.

I tried to use \protect. This will return the correct value, not the command. But I get Missing number, treated as zero in my if-clause.

I think this is a rather easy question. But I did not find a solution by googling. Also this may be because I was looking for the wrong searching term.

I hope somebody can help me or post a website where I can find the solution myself.

Answer 1

You have to \edef the macro \oldvalue or use

\let\oldvalue\storedvalue

because \let\oldvalue\getoldvalue would make a copy of \getoldvalue, not of its expansion.

\documentclass{article}

\begin{document}

\newcommand{\storedvalue}{1}
\newcommand{\getstoredvalue}{\storedvalue}
\newcommand{\resetstoredvalue}{Resetting}

Some text

\edef\oldvalue{\getstoredvalue} % or \let\oldvalue\storedvalue
\renewcommand{\storedvalue}{0}

Some text which needs the stored value to be changed

\ifnum\oldvalue>0
    \resetstoredvalue{}%
\fi

\end{document}

Note that no % should appear after 0 in \ifnum context.