我如何定义一个 beamer overlay 规范，beamer:0比如beamerframe key：
\documentclass{beamer}
\makeatletter
\define@key{beamerframe}{hide}[true]{%
%<--- definition of the beamer:0 switch??
}
\makeatother
\begin{document}
\begin{frame}[hide] %<-- has now overlay specification beamer:0
example text
\end{frame}
\end{document}
提前谢谢！
答案1
\documentclass{beamer}
\usepackage{xpatch}
\makeatletter
\newif\ifbeamer@hide
\define@key{beamerframe}{hide}[true]{\beamer@hidetrue}
\BeforeBeginEnvironment{frame}{\beamer@hidefalse}
\xpatchcmd{\beamer@@@@frame}{%
\gdef\beamer@whichframes{#1}%
}{
\ifbeamer@hide
\gdef\beamer@whichframes{beamer:0}%
\else
\gdef\beamer@whichframes{#1}%
\fi
}{}{}
\makeatother
\begin{document}
\begin{frame}
content...
\end{frame}
\begin{frame}[hide] %<-- has now overlay specification beamer:0
example text
\end{frame}
\begin{frame}
content...s
\end{frame}
\end{document}