<<< 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") ] >>> eqn x sup 1 + x sup a + H sup a + H sup 1