<<< native
[ EDelimited
    "("
    ")"
    [ Right (EFraction NormalFrac (EIdentifier "y") (EIdentifier "z"))
    ]
, ESymbol Bin "+"
, EDelimited
    "("
    ")"
    [ Right (EFraction NormalFrac (EIdentifier "y") (EIdentifier "z"))
    ]
]
>>> eqn
left ( y over z right ) + left ( y over z right )