\input regression-test.tex
\DocumentMetadata{}
\documentclass{ltx-talk}
\NewDocumentCommand\lecture{O{}mm}{\TYPE{LECTURE KEPT}}
\usepackage[ignorenonframetext]{osglecture-modes-ltxtalk}
\ExplSyntaxOn
\cs_new_protected:Npn \test_keep_end:
  { \END \osglecture_modes_scan: }
\osglecture_modes_declare_allowed_command:nn { END } { test_keep_end: }
% Defined here, in the preamble, rather than inline inside the frame
% body below: a beamer/ltx-talk frame body is pre-tokenized before its
% own content runs, so \ExplSyntaxOn inside it does not retroactively
% fix "_"'s catcode for tokens already grabbed as part of the frame
% argument -- calling a preamble-defined helper avoids that.
\cs_new_protected:Npn \checksectionarg
  {
    \str_if_eq:eeTF { \tl_to_str:c { l__talk_section_tl } } { Organisatorisches }
      { \TYPE { section-arg:passed } }
      { \TYPE { section-arg:FAILED=\tl_to_str:c{l__talk_section_tl} } }
  }
\ExplSyntaxOff
\begin{document}
\START
\lecture{Introduction}{intro}
\mode<presentation>
\section{Organisatorisches}
\begin{frame}
  \checksectionarg
\end{frame}
\END
\end{document}