%% 
%%  Ein DANTE-Edition Beispiel
%% 
%%  Beispiel 04-20-1 auf Seite 117.
%% 
%%  Copyright (C) 2010 Voss
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 

% Show page(s) 1

\PassOptionsToClass{}{beamer}
\documentclass{beamer}
\AtBeginDocument{\Huge}% nur fuer Demo


\defbeamertemplate{list item}{rarrow}{$\rightarrow$}
\defbeamertemplate{list item}{Rarrow}{$\Rightarrow$}\setbeamertemplate{list item}[rarrow]{}
\newcounter{bcnt}
\newenvironment{bList}{\list{\usebeamertemplate{list item}}{\usecounter{bcnt}}}{\endlist}


\begin{document}
\begin{frame}{foo}{bar}
\begin{columns}[t]\begin{column}{0.3\textwidth}
\begin{bList} \item foo \item bar \end{bList}
\end{column} \setbeamertemplate{list item}[Rarrow]{}
\begin{column}{0.3\textwidth}
\begin{bList} \item foo \item bar \end{bList}
\end{column}
\addtobeamertemplate{list item}{\thebcnt: }{}
\begin{column}{0.3\textwidth}
\begin{bList} \item foo \item bar \end{bList}
\end{column}\end{columns}
\end{frame}
\end{document}
