A = "x" <x> X <i> Integer.
A1 = <a1> A <a2> A.
X = .
B = <l> Long.
C = <i1> Integer <i2> Integer.
T : R | S.
S = <v> Vector <a> A.
U = Integer Long.
V = <b> B *extends* Vector .
V1 = *extends* Vector .