Shaka Scheme - Build a Scheme Interpreter | Jared Shimabukuro

Shaka Scheme is a Scheme interpreter constructed in C++ that implements the Scheme programming language standard that is defined in the Revised7 Report on the Algorithmic Language Scheme (R7RS).

// (+ z1 ...)
Args add_numbers(Args args) {

  if (args[0]->get_type() != Data::Type::NUMBER) {
    throw TypeException(117,
                        "STDPROC: Incorrect argument type to Native "
                            "Procedure: "
                            "+");
  }

  shaka::Number result = shaka::Number(0);
  for (std::size_t i = 0; i < args.size(); i++) {
    result = result + args[i]->get<shaka::Number>();
  }

  Args result_vector;
  NodePtr result_value = create_node(result);
  result_vector.push_back(result_value);

  return result_vector;
}