Existing CAS commands --> Prime discussion

[parisse]

Some comments:
as_function_of is more an internal function than something else, it is used by locus to build a function from a construction. For example in an Xcas session enter
a:=1;
b:=a*x+1;
as_function_of(b,a)

is_prime is the same as is_pseudoprime on the Prime, it links to PARI in Xcas.

c1oc2 and c1op2 are there in Xcas, it's a 1 not a l, read this as compose permutation as a cycle 1 with permutation as a cycle 2 or as a permutation 2.
Same for p1oc2 and p1op2

conique_reduite and quadrique_reduite have been translated to reduced_conic and reduced_quadric, the French keywords work only if you have selected French.

realroot is not the same functionnality as zeros or proot. zeros is an exact algorithm to find exact roots, proot is an approx algorithm to find approx roots, while realroot is an exact algorithm to find isolation interval for roots, it means you have a proof that there is 1 and exactly 1 root in the returned intervals.

makevector is not really useful, just put bracket on the sequence.

Z/pZ is available on the Prime, but you must enter %% instead of % in Xcas.

I don't want to make change to the parser that could have side effects, therefore I don't want to enable user_operator .

combine: it was added for maple compat.
SortA and SortD: added for TI compat.

count_eq, count_inf and count_sup were added at the request of teachers using Xcas, because they don't want to explain how to use count : count is indeed more elaborate since you must pass a function to a command