\newcommand{\isastyle}{\tt}			% to set    isa font etc.
\newcommand{\isamodify}{\it}			% to modify isa font etc.
\newcommand{\isainline}[2][]{\isastyle{}#1{}#2}
						% wrapping text for INLINE mode
\newcommand{\isaescape}[1]{\mbox{#1}}		% wrapping text for ESC mode
\newcommand{\isabegin}[1]{\isastyle{}#1\begin{tabbing}	% begin of ISA mode
xxxxxxxx\=xxxxxxxx\=xxxxxxxx\=xxxxxxxx\=xxxxxxxx\=xxxxxxxx\=
xxxxxxxx\=xxxxxxxx\=xxxxxxxx\=xxxxxxxx\=xxxxxxxx\=xxxxxxxx\=
\kill}
\newcommand{\isaend}{\end{tabbing}}		% end of ISA mode

\chardef\tttilde=`\~     % A tilde for \tt font
\chardef\ttbackslash=`\\ % A backslash for \tt font
%WRONG for \it: \chardef\ttlbrace=`\{    % A left brace for \tt font
%WRONG for \it: \chardef\ttrbrace=`\}    % A right brace for \tt font

