First \autoref to table or figure bold, subsequent ones normal

Question

I am forced would like to typeset the first \autoref to any table or figure in boldface and all subsequent references in normalfont. How can I achieve this, without having to manually insert \textbf at the first occurrence as shown below?

\documentclass{article}

\usepackage{hyperref}

\begin{document}

The first reference to~\textbf{\autoref{tab:a}} should be bold.

\begin{table}
\caption{A table}\label{tab:a}
\end{table}

Further references to~\autoref{tab:a} should be normal.

\end{document}

I found a solution for a very similar problem here, but it works for \ref rather than \autoref.

Answer 1

The usual procedure is to add a check for an already defined macro storing in its name the current label; if it's still undefined, make the \autoref bold and define the macro.

Since we need to overload \autoref, we need some care.

\documentclass{article}
\usepackage{letltxmacro}
\usepackage[colorlinks]{hyperref}

\AtBeginDocument{%
  \LetLtxMacro\hyperrefautoref\autoref
  \LetLtxMacro\autoref\firstboldautoref
}
\makeatletter
\DeclareRobustCommand\firstboldautoref{\@firstboldautoref}
\def\@firstboldautoref#1#{%
  \def\fb@autoref@star{#1}%
  \fb@autoref
}
\def\fb@autoref#1{%
  \ifcsname boldautoref@#1\endcsname
    \expandafter\hyperrefautoref\fb@autoref@star{#1}%
  \else
    \global\expandafter\let\csname boldautoref@#1\endcsname\@empty
    \textbf{\expandafter\hyperrefautoref\fb@autoref@star{#1}}%
  \fi
}
\makeatother


\begin{document}

\section{Test}\label{sec:a}

The first reference to~\autoref*{sec:a} should be bold.

The first reference to~\autoref{tab:a} should be bold.

\begin{table}
\caption{A table}\label{tab:a}
\end{table}

Further references to~\autoref*{sec:a} should be normal.

Further references to~\autoref{tab:a} should be normal.

\end{document}

Answer 2

A small 'overload' of \autoref (not fully finished), adding the label to an expl3 \seq list and checking whether it was added already.

\documentclass{article}

\usepackage{hyperref}
\usepackage{letltxmacro}
\usepackage{xparse}

\newcommand{\autorefformat}[1]{%
  {\bfseries#1}%
}

\ExplSyntaxOn
\seq_new:N \g_ref_alreadyused_seq% Define a sequence list

\makeatletter
\AtBeginDocument{
  \LetLtxMacro\autoref@@orig\autoref% Get the old definition of \autoref
  \RenewDocumentCommand{\autoref}{sm}{%
    \seq_if_in:NnTF \g_ref_alreadyused_seq {#2} {
      \IfBooleanTF{#1}{% Yes, starred version
        \autoref@@orig*{#2}
      }{
        \autoref@@orig{#2}
      }
    }{% No, it's not yet used, apply \autorefformat
      \seq_gput_right:Nn \g_ref_alreadyused_seq {#2}
      \autorefformat{%
      \IfBooleanTF{#1}{% Starred version
        \autoref@@orig*{#2}
      }{
        \autoref@@orig{#2}
      }
      }
    }% End of \seq_if_in:F 
  }
}
\makeatother
\ExplSyntaxOff

\begin{document}

The first reference to~\textbf{\autoref{tab:a}} should be bold.

\begin{table}
\caption{A table}\label{tab:a}
\end{table}

Further references to~\autoref{tab:a} should be normal.

\end{document}

Alternate version: Using a wrapper macro named,say, \autorefext, that checks similarly for the label being used already. The third, optional argument defaults to \bfseries.

\documentclass{article}

\usepackage{hyperref}
\usepackage{xparse}

\newcommand{\autorefformat}[1]{%
  {\bfseries#1}%
}

\ExplSyntaxOn
\seq_new:N \g_ref_alreadyused_seq

\NewDocumentCommand{\autorefext}{smO{\bfseries}}{%
  \seq_if_in:NnTF \g_ref_alreadyused_seq {#2} {
    \IfBooleanTF{#1}{
      \autoref*{#2}
    }{
      \autoref{#2}
    }
  }{%
    \seq_gput_right:Nn \g_ref_alreadyused_seq {#2}
    {#3%
      \IfBooleanTF{#1}{
        \autoref*{#2}
      }{
        \autoref{#2}
      }
    }
  }
}

\ExplSyntaxOff

\begin{document}

The first reference to~\autorefext{tab:a} should be bold.

\begin{table}
\caption{A table}\label{tab:a}
\end{table}

Further references to~\autorefext{tab:a} should be normal.

\end{document}