<<< tex
\newcommand{\abc}{5}
\newcommand{\xyz}[2][x]{%
#1 + #2%
}
\renewcommand{%
\phi%
}{%
\theta%
}
% comment
\newcommand{\aaa}{\b{2}}
\renewcommand{\phi}{\aaa}
\newcommand{\b}[1]{#1}

\newenvironment{ary}
{\begin{array}{cc}
\hline}
{\hline
\end{array}}

\phi
\abc
\xyz[y] {3}
\xyz 3
\xyz \alpha

\begin{ary}
2 & 3\\
4 & 5
\end{ary}

>>> native
[ ENumber "2"
, ENumber "5"
, EGrouped [ EIdentifier "y" , ESymbol Bin "+" , ENumber "3" ]
, EGrouped [ EIdentifier "x" , ESymbol Bin "+" , ENumber "3" ]
, EGrouped
    [ EIdentifier "x" , ESymbol Bin "+" , EIdentifier "\945" ]
, EArray
    [ AlignCenter , AlignCenter ]
    [ [ [ ENumber "2" ] , [ ENumber "3" ] ]
    , [ [ ENumber "4" ] , [ ENumber "5" ] ]
    ]
]