<<< native
[ EArray
    [ AlignCenter , AlignCenter , AlignCenter ]
    [ [ [ EFraction
            NormalFrac
            (EGrouped [ EIdentifier "a" , ESymbol Bin "+" , ENumber "1" ])
            (ENumber "2")
        ]
      , [ EIdentifier "b" ]
      , [ EIdentifier "c" ]
      ]
    , [ [ EIdentifier "x" ]
      , [ EGrouped
            [ EFraction NormalFrac (ENumber "2") (ENumber "3")
            , EIdentifier "y"
            , ESymbol Bin "+"
            , ENumber "5"
            ]
        ]
      , [ EIdentifier "z" ]
      ]
    , [ [ ENumber "1" ]
      , [ ENumber "2" ]
      , [ EFraction
            NormalFrac
            (EGrouped [ EIdentifier "a" , ESymbol Bin "+" , ENumber "5" ])
            (ENumber "3")
        ]
      ]
    ]
]
>>> tex
\begin{matrix}
\frac{a + 1}{2} & b & c \\
x & {\frac{2}{3}y + 5} & z \\
1 & 2 & \frac{a + 5}{3} \\
\end{matrix}