taple.tex

\documentclass{jarticle}

\makeatletter

% 第一引数：識別子
% 第二引数：コンマ区切りのやつ
\def\taple#1#2{%
	\expandafter\newcount\csname #1@xx@i\endcsname
	\expandafter\newcount\csname #1@xx@ii\endcsname
	\@nameuse{#1@xx@i} = -1
	\@nameuse{#1@xx@ii} = 0
	\@for\mem:=#2\do{ \advance\@nameuse{#1@xx@i} by 1 }
	\left(%
	\@for\mem:=#2\do{%
		\ifnum \@nameuse{#1@xx@ii}<\@nameuse{#1@xx@i}\relax%
			\mem,%
			\advance\@nameuse{#1@xx@ii} by 1%
		\else%
			\mem%
		\fi%
	}
	\right)%
}
\makeatother

\begin{document}

$\taple{a}{ \taple{A}{0, 9}, \taple{b}{1, 2}, \taple{c}{3, 4} }$

\end{document}