Make env a class.

code/compiler/13/env.hpp

@@ -2,7 +2,8 @@
 #include <memory>
 #include <string>
 
-struct env {
+class env {
+    public:
         virtual ~env() = default;
 
         virtual int get_offset(const std::string& name) const = 0;
@@ -11,10 +12,12 @@ struct env {
 
 using env_ptr = std::shared_ptr<env>;
 
-struct env_var : public 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)) {}
 
@@ -22,10 +25,12 @@ struct env_var : public env {
         bool has_variable(const std::string& name) const;
 };
 
-struct env_offset : public env {
+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)) {}