\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