A = "a" <b1> B <c1> C [D] "enda".
B : E | F.
C = .
D = "d" .
E = "e".
F = <g1> G <h1> H <a1> A.
G =.
H = "h".

Main = .
PrintingVisitor = .
TreeStructureVisitor = <indent> Integer.
SummingVisitor = <total> Integer.