\input regression-test.tex
\documentclass{article}
\usepackage[mode=script]{osglecture-modes}
\usepackage{osgstyler}

\ExplSyntaxOn
\DeclareInstance{osgstyler-block}{ftblock}{standard}{}
\ExplSyntaxOff

\NewOsgStyledEnvironment{block}{ftblock}{none}[1]{#1}
\NewOsgStyledEnvironment{twoarg}{ftblock}{none}[2]{#1~--~#2}
\NewOsgStyledEnvironment{threearg}{ftblock}{none}[3]{#1/#2/#3}

\begin{document}
\START
\begin{block}{My Title}
  \TYPE{block-body=shown}
\end{block}
\begin{twoarg}{Left}{Right}
  \TYPE{twoarg-body=shown}
\end{twoarg}
\begin{threearg}{A}{B}{C}
  \TYPE{threearg-body=shown}
\end{threearg}
\begin{block}<script>{Active}
  \TYPE{active-shown}
\end{block}
\begin{block}<slides>{Inactive}
  \TYPE{inactive-shown}
\end{block}
\TYPE{done}
\END
\end{document}