<<< native
[ EDelimited
    "("
    ")"
    [ Right
        (EArray
           [ AlignCenter , AlignCenter , AlignCenter ]
           [ [ [ ENumber "1" ] , [ ENumber "0" ] , [ ENumber "0" ] ]
           , [ [ ENumber "0" ] , [ ENumber "1" ] , [ ENumber "0" ] ]
           , [ [ ENumber "0" ] , [ ENumber "0" ] , [ ENumber "1" ] ]
           ])
    ]
]
>>> tex
\begin{pmatrix}
1 & 0 & 0 \\
0 & 1 & 0 \\
0 & 0 & 1
\end{pmatrix}