bloglang/13/env.hpp

#pragma once
#include <memory>
#include <string>

class env {
    public:
        virtual ~env() = default;

        virtual int get_offset(const std::string& name) const = 0;
        virtual bool has_variable(const std::string& name) const = 0;
};

using env_ptr = std::shared_ptr<env>;

class env_var : public env {
    private:
        std::string name;
        env_ptr parent;

    public:
        env_var(std::string n, env_ptr p)
            : name(std::move(n)), parent(std::move(p)) {}

        int get_offset(const std::string& name) const;
        bool has_variable(const std::string& name) const;
};

class env_offset : public env {
    private:
        int offset;
        env_ptr parent;

    public:
        env_offset(int o, env_ptr p)
            : offset(o), parent(std::move(p)) {}

        int get_offset(const std::string& name) const;
        bool has_variable(const std::string& name) const;
};