Function: poldegree
Section: polynomials
C-Name: gppoldegree
Prototype: GDn
Help: poldegree(x,{v}): degree of the polynomial or rational function x with
respect to main variable if v is omitted, with respect to v otherwise.
For scalar x, return 0 if x is non-zero and -oo otherwise.
Doc: degree of the polynomial $x$ in the main variable if $v$ is omitted, in
the variable $v$ otherwise.
The degree of $0$ is \kbd{-oo}. The degree of a non-zero scalar is $0$.
Finally, when $x$ is a non-zero polynomial or rational function, returns the
ordinary degree of $x$. Raise an error otherwise.
Variant: Also available is
\fun{long}{poldegree}{GEN x, long v}, which returns \tet{-LONG_MAX} if $x = 0$
and the degree as a \kbd{long} integer.