<<< 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" ])
    ]
]
>>> eqn
left ( {a + b} right ) = left ( alpha over beta right ) = left [ {a + b} right )