\input regression-test.tex
\DocumentMetadata{}
\documentclass{ltx-talk}
\usepackage{ltxtalk-theme-hawk}
\useltxtalktheme{hawk}

\title{Insert-Element-Test}
\author{A. Beispiel}
\date{\today}

\begin{document}
\START

\ExplSyntaxOn
% Sanity check: all six built-in instances got registered, and defining a
% custom one plus editing a built-in one does not error.
\clist_map_inline:nn
  {
    pagenumber, totalframes, pagenumber-of-total,
    section-pagenumber, sectionheading, subsectionheading
  }
  {
    \IfInstanceExistsTF { ltxtalk-element } { #1 }
      { \TYPE { instance-#1:passed } }
      { \TYPE { instance-#1:FAILED } }
  }
\DeclareInstance { ltxtalk-element } { my-counter } { counter } { source = XY }
\IfInstanceExistsTF { ltxtalk-element } { my-counter }
  { \TYPE { instance-my-counter:passed } }
  { \TYPE { instance-my-counter:FAILED } }
\ExplSyntaxOff

% \InsertLTXTalkElement wraps the protected \UseInstance (like
% \LTXTalkNavigation) and so cannot be checked via expansion; the rendered
% values below were verified once with pdftotext:
%   frame A: [pagenumber]=1  [totalframes]=3  [pagenumber-of-total]=1/3
%   frame B: [pagenumber-of-total]=2/3  [sectionheading]=1 Erster Abschnitt
%            [subsectionheading]=1.1 Erster Unterabschnitt
%            [section-pagenumber]=Erster Abschnitt -- 2 (en-dash ligature)
%   frame C (after the EditInstance calls below):
%            [pagenumber-of-total]=3 of 3  [sectionheading]=Erster Abschnitt

\begin{frame}
  \frametitle{A}
  [pagenumber]=\InsertLTXTalkElement{pagenumber}

  [totalframes]=\InsertLTXTalkElement{totalframes}

  [pagenumber-of-total]=\InsertLTXTalkElement{pagenumber-of-total}

  [my-counter]=\InsertLTXTalkElement{my-counter}
\end{frame}

\section{Erster Abschnitt}
\subsection{Erster Unterabschnitt}

\begin{frame}
  \frametitle{B}
  [pagenumber-of-total]=\InsertLTXTalkElement{pagenumber-of-total}

  [sectionheading]=\InsertLTXTalkElement{sectionheading}

  [subsectionheading]=\InsertLTXTalkElement{subsectionheading}

  [section-pagenumber]=\InsertLTXTalkElement{section-pagenumber}
\end{frame}

\ExplSyntaxOn
\EditInstance { ltxtalk-element } { pagenumber-of-total } { separator = { ~of~ } }
\EditInstance { ltxtalk-element } { sectionheading } { numbered = false }
\ExplSyntaxOff

\begin{frame}
  \frametitle{C}
  [pagenumber-of-total, edited separator]=%
  \InsertLTXTalkElement{pagenumber-of-total}

  [sectionheading, unnumbered]=\InsertLTXTalkElement{sectionheading}
\end{frame}

\end{document}