roza/lib/VM.hpp

#ifndef roza_VM_HPP
#define roza_VM_HPP

#include "commons.hpp"
#include "Program.hpp"
#include "StatusLog.hpp"

namespace roza
{
  using unop_t = std::function<std::shared_ptr<Value>
                               (std::shared_ptr<Value>)>;

  using binop_t = std::function<std::shared_ptr<Value>
                                (std::shared_ptr<Value>,
                                 std::shared_ptr<Value>)>;

  using var_map = std::unordered_map<int, std::shared_ptr<Value>>;

  struct Frame {
    var_map locals;
    size_t pc;
    size_t sp;
    size_t bp;
  };

  class VM
  {
  public:
    explicit VM(StatusLog& log);
    virtual ~VM();

    void exec(std::shared_ptr<Program> program);
    std::string string() const;

  private:
    StatusLog& m_log;
    std::array<param_t, 4096> m_stack;
    std::shared_ptr<Program> m_last_program;
    var_map m_globals;
    std::vector<Frame> m_frames;
    size_t m_sp = 0;
    size_t m_bp = 0;
    size_t m_pc = 0;

    void push(param_t param);
    param_t pop();

    void apply_binop(std::shared_ptr<Program> program, binop_t op);
    void apply_unop(std::shared_ptr<Program> program, unop_t op);
  };
}

#endif