The Perl, C++, and Python code here was written by me. The calculator-language code examples were contributed by students.
As silly as it is to have to do this, in these times I guess it has to be done: all this stuff is copyrighted under the GNU public license . No warranty is expressed or implied for any of it.
By the way, I can't vouch for the correctness of the syntax of the calculator-language, since I don't know those languages.