I feel building your own is probably not the best way to benefit from a CAS, unless you are doing it for fun! But I had this question too in the past and found

I feel building your own is probably not the best way to benefit from a CAS, unless you are doing it for fun! But I had this question too in the past and found some resources, including the fact that SymPy is a good project to learn from. —- https://www.sympy.org/en/index.html https://www.sympy.org/en/index.html https://www.google.com/books/edition/Computer_Algebra/rOU3EAAAQBAJ?hl=en https://www.google.com/books/edition/Computer_Algebra/rOU3EA... http://sarabander.github.io/sicp/html/2_002e3.xhtml#g_t2_002e3_002e2 http://sarabander.github.io/sicp/html/2_002e3.xhtml#g_t2_002...