General ⇒ Redefining the \label macro doesn't work

[littlegolem]

Hi! For making it easier to find specific equations in the code, I have created a flag PRINTLABELS that enables the equation labels to be written above the equations and put this code in the preamble:

Code: Select all

\robustify{\label}
\iftoggle{PRINTLABELS}{
    \let\oldLabel\label
    \renewrobustcmd{\label}[1]{\oldLabel{#1}\text{Equation #1}\\}
}{}

where robustify and renewrobustcmd are macros defined in the etoolbox package, and PRINTLABELS is either false or true. I'm creating PRINTLABELS before this code is processed, and even though I set PRINTLABELS to true, the code has no effect. I also tried to put

Code: Select all

\renewcommand{\label}[1]{}

in the preamble, but even this simple code doesn't have any effect. Why isn't anything happening?

[localghost]

Before you try to reinvent the wheel you should take a look at the showlabels package. Furthermore there are editors which support keeping track of used labels (at least Kile and TeXnicCenter if I remember right).


Thorsten

[littlegolem]

Thanks, the showlabels package was just right for me. However, I still wonder why my small invention did not work. Isn't it possible to use \renewcommand on the \label macro?

[localghost]

[…] Isn't it possible to use \renewcommand on the \label macro?

The package does nothing else. Just take a look at its (very short) source code.

[cgnieder]

... However, I still wonder why my small invention did not work...

It does. You probably haven't set the toggle to true. Or maybe you've set it only to true after the possible definition? This works:

Code: Select all

\documentclass{article}
\usepackage{mathtools}
\usepackage{etoolbox}

\newtoggle{PRINTLABELS}
\toggletrue{PRINTLABELS}% <= this enables the new definition
\robustify{\label}

\iftoggle{PRINTLABELS}{% <= you should set the % here if you want to avoid spurious spaces.
    \let\oldLabel\label
    \renewrobustcmd{\label}[1]{\oldLabel{#1}\text{~Equation #1}}%
}{}
\begin{document}
Text\label{bla}
\end{document}

A more flexible definition would ask for the toggle inside the new definition (besides there being the handy showlabels package):

Code: Select all

\documentclass{article}
\usepackage{mathtools}
\usepackage{etoolbox}

\newtoggle{PRINTLABELS}
\let\oldLabel\label

\renewrobustcmd\label[1]{%
  \iftoggle{PRINTLABELS}{~Equation~#1}{}\oldLabel{#1}}

\begin{document}
Text\label{bla}

\toggletrue{PRINTLABELS}
Text\label{blub}
\end{document}

Regards