RPLSW(L,V)
[Rational polynomial list special write.  L is a list of rational
polynomials in r variables, r>=1.  V is a variable list of length r.
The polynomials in L are special written in the output stream.]
     safe L',L1.
(1)  L'=L;  while L'~=() do { ADV(L';L1,L');  RPSW(L1,V) };
     return..