<<< native
[ EDelimited
    "("
    ")"
    [ Right
        (EGrouped [ EIdentifier "a" , ESymbol Bin "+" , EIdentifier "b" ])
    ]
, ESymbol Rel "="
, EDelimited
    "("
    ")"
    [ Right
        (EFraction NormalFrac (EIdentifier "\945") (EIdentifier "\946"))
    ]
, ESymbol Rel "="
, EDelimited
    "["
    ")"
    [ Right
        (EGrouped [ EIdentifier "a" , ESymbol Bin "+" , EIdentifier "b" ])
    ]
]
>>> tex
\left( {a + b} \right) = \left( \frac{\alpha}{\beta} \right) = \left\lbrack {a + b} \right)