RPSWL(A,V)
[Rational polynomial special write,linear. A is a rational polynomial.
V is a variable list for A. A is written in the output stream in a
linearized form which can be read by rpsr. No terminating $]
     safe r.
(1)  r=LENGTH(V);  A'=SDIPFP(r,A);  DIPSWL(A',V,1);
     return..