texmath-0.12.5: test/roundtrip/boxed.native

[ EBoxed
    (EGrouped
       [ ESuper (EIdentifier "x") (ENumber "2")
       , ESymbol Bin "+"
       , ESuper (EIdentifier "y") (ENumber "2")
       , ESymbol Bin "+"
       , ESuper (EIdentifier "z") (ENumber "2")
       ])
]