Remove last character from decription label in cross reference label

Question

I read how to make a reference that has as a label the label of a description label (Reference name of description list item in LaTeX):

\makeatletter
\let\orgdescriptionlabel\descriptionlabel
\renewcommand*{\descriptionlabel}[1]{%
  \let\orglabel\label
  \let\label\@gobble
  \phantomsection
  \edef\@currentlabel{#1}%
  %\edef\@currentlabelname{#1}%
  \let\label\orglabel
  \orgdescriptionlabel{#1}%
}
\makeatother

This works. However, often description labels end with a special character, like : or ,, which should not be part of the reference label. How can I remove this character from the reference label?

Edit:

Tried:

\usepackage{xstring}
...
  \edef\@currentlabel{\StrGobbleRight{#1}{1}}%
...

But that seems not to work for some reason.

Edit

Here is a full document (from the link above):

\documentclass{article}
\usepackage{hyperref}
\usepackage{nameref}

\makeatletter
\let\orgdescriptionlabel\descriptionlabel
\renewcommand*{\descriptionlabel}[1]{%
  \let\orglabel\label
  \let\label\@gobble
  \phantomsection
  \edef\@currentlabel{#1}%
  %\edef\@currentlabelname{#1}%
  \let\label\orglabel
  \orgdescriptionlabel{#1}%
}
\makeatother

\begin{document}

\section{Definitions}
\begin{description}
    \item [Vehicle\label{itm:vehicle}] Something
    \item [Bus\label{itm:bus}] A type of \ref{itm:vehicle}
    \item [Car\label{itm:car}] A type of \ref{itm:vehicle} smaller than a    \ref{itm:bus}
\end{description} 

The item `\ref{itm:bus}' is listed on page~\pageref{itm:bus} in section~\nameref{itm:bus}.

\end{document}

Answer 1

You can select to remove a final punctuation based on \spacefactor:

\documentclass{article}
\usepackage{xstring}
\usepackage{hyperref}
\usepackage{nameref}

\makeatletter
\let\orgdescriptionlabel\descriptionlabel
\renewcommand*{\descriptionlabel}[1]{%
  \begingroup
  \let\label\@gobble
  \phantomsection
  \protected@edef\daniel@currentlabel{#1}%
  \sbox\z@{\daniel@currentlabel\xdef\daniel@sf{\the\spacefactor}}%
  \ifnum\daniel@sf>1000
    \noexpandarg
    \expandafter\StrGobbleRight\expandafter{\daniel@currentlabel}{1}[\daniel@currentlabel]%
  \fi
  \def\x{%
    \expandafter\endgroup
    \expandafter\def\expandafter\@currentlabelname
    \expandafter{\daniel@currentlabel}}%
  \x
  \orgdescriptionlabel{#1}%
}
\makeatother

\begin{document}

\section{Definitions}
\begin{description}
    \item [Vehicle\label{itm:vehicle}] Something
    \item [Bus,\label{itm:bus}] A type of \nameref{itm:vehicle}
    \item [Car\label{itm:car}] A type of \nameref{itm:vehicle} smaller than a \nameref{itm:bus}
\end{description}

References: `\nameref{itm:bus}' and `\nameref{itm:car}'.
\end{document}

After a punctuation sign, the space factor is greater than 1000 (with standard \nonfrenchspacing setup; if you use \frenchspacing, also load amsthm that adjusts things so the space factor can still be used).

In order to use \ref instead of \nameref, just a small change is needed; I would recommend being consistent in using \ref for numbers and \nameref for text, but I can understand the need of not changing existing documents.

\documentclass{article}
\usepackage{xstring}
\usepackage{hyperref}

\makeatletter
\let\orgdescriptionlabel\descriptionlabel
\renewcommand*{\descriptionlabel}[1]{%
  \begingroup
  \let\label\@gobble
  \phantomsection
  \protected@edef\daniel@currentlabel{#1}%
  \sbox\z@{\daniel@currentlabel\xdef\daniel@sf{\the\spacefactor}}%
  \ifnum\daniel@sf>1000
    \noexpandarg
    \expandafter\StrGobbleRight\expandafter{\daniel@currentlabel}{1}[\daniel@currentlabel]%
  \fi
  \def\x{%
    \expandafter\endgroup
    \expandafter\def\expandafter\@currentlabel
    \expandafter{\daniel@currentlabel}}%
  \x
  \orgdescriptionlabel{#1}%
}
\makeatother

\begin{document}

\section{Definitions}
\begin{description}
    \item [Vehicle\label{itm:vehicle}] Something
    \item [Bus,\label{itm:bus}] A type of \ref{itm:vehicle}
    \item [Car\label{itm:car}] A type of \ref{itm:vehicle} smaller than a \ref{itm:bus}
\end{description}

References: `\ref{itm:bus}' and `\ref{itm:car}'.
\end{document}