Are there any currently working examples with this code?

[andersjohansson]

This seems like a promising project, but as far as I can tell none of the current code is production status, right now, right? Or rather, there doesn't seem to be any example I can get to work at all, and the tex-files in the repository don't match the dtx-file.

It's a pity, because it seems like a a good and general way for breadcrumbs.

Maybe you could add a note about the status? Because I downloaded it in the hope of having something that I could kind of use (even if it's beta).
Cheers,
Anders

[vermiculus]

I'm working on completing the package, but there are some funky issues to sort out – I'll keep you posted 😄

It's worth noting that vermiculus/lt3stack contains the implementation of the breadcrumb datastructure, so you may have some luck with implementing. Recently, I've been trying to hook onto \@sect (arguments 2 and 7 are of interest) with xpatch to manage the stack.

[vermiculus]

Here's a sortof-working example:

% arara: pdflatex
\documentclass{article}
\usepackage{filecontents}
\begin{filecontents*}{brdcrmbs.sty}
% wget https://raw.githubusercontent.com/vermiculus/lt3wstack/master/lt3wstack.{tex,sty}
\RequirePackage{expl3,xpatch,xparse,lt3wstack}

\ExplSyntaxOn

\wstack_new:N \l__breadcrumbs_nav_wstack

\xapptocmd \@sect {
  \breadcrumbs_push:nn {#2} {#7}
%  \mark { \breadcrumbs_display: }
} {}{}

\cs_new:Npn \breadcrumbs_push:nn #1 #2 {
  \wstack_push:Nnn
    \l__breadcrumbs_nav_wstack
    { 0 - #1 } {#2}
}

\cs_new:Npn \breadcrumbs_display: {
  \wstack_use:Nn \l__breadcrumbs_nav_wstack {~$\to$~}
}

\NewDocumentCommand \ShowBreadcrumbs {} { \topmark }
\NewDocumentCommand \DispBreadcrumbs {} { \breadcrumbs_display: }
\ExplSyntaxOff
\endinput
\end{filecontents*}

\usepackage{brdcrmbs,fancyhdr}

\pagestyle{fancy}
\fancyhf{}
\renewcommand\headrulewidth{0pt}
\renewcommand\footrulewidth{0pt}
\chead{\DispBreadcrumbs}
\cfoot{\thepage}

\begin{document}
\section{section}
\subsection{subsection}
\DispBreadcrumbs
\clearpage
\subsection{subsection}
\subsubsection{subsubsection}
\DispBreadcrumbs
\end{document}

\usepackage{mwe}
\begin{document}
\Blinddocument
\end{document}

I'd like to be using \mark for this, but the stack structure is \protected (by expl3) preventing it from expanding in the header. At the moment, this implementation is subject to strange bugs when sections begin pages.