<<< native [ ESuper (EIdentifier "x") (ENumber "1") , ESymbol Bin "+" , ESuper (EIdentifier "x") (EIdentifier "a") , ESymbol Bin "+" , ESuper (EIdentifier "H") (EIdentifier "a") , ESymbol Bin "+" , ESuper (EIdentifier "H") (ENumber "1") ] >>> tex x^{1} + x^{a} + H^{a} + H^{1}