aocpp/lib/include/intcode/Interpreter.hpp

#ifndef INTCODE_INTERPRETER_HPP_
#define INTCODE_INTERPRETER_HPP_

#include <variant>

#include <intcode/Machine.hpp>
#include <Overload.hpp>
namespace intcode {

struct Input {
ValueType &pos;
};

struct Output {
ValueType val;
};

struct Halt {};

auto StepInput(Machine & m, ValueType input) -> void;

auto StepOutput(Machine & m) -> ValueType;

auto Step(Machine & m) -> std::variant<Input, Output, Halt>;

struct BadInstruction : public std::runtime_error {
  explicit BadInstruction(char const* what);
};

template <class Fin, class Fout>
auto Run(Machine & machine, Fin input, Fout output) -> void {
  while (std::visit(overloaded{
    [](Halt) { return false; },
    [&](Input arg) {
      arg.pos = input();
      return true;
    },
    [&](Output arg) {
      output(arg.val);
      return true;
    }},
    Step(machine)));
}

} // namespace

#endif