You can use compiler_interface hpp outside

core_compiler_interface.hpp

@@ -11,8 +11,8 @@ struct Ast_Lambda;
 struct Ast_Type;
 struct Ast_Expr;
 
-#ifndef CORE_STRINGS
-#define CORE_STRINGS
+#ifndef CORE_BASE
+#define CORE_BASE
 struct String{
   uint8_t *str;
   int64_t len;
@@ -25,6 +25,33 @@ union Intern_String{  // Basically just String
     int64_t len; 
   };
 };
+
+template<class T>
+struct Array {
+  void *allocator;
+  T  *data;
+  int64_t cap;
+  int64_t len;
+};
+
+template<class T>
+struct List_Node{
+  List_Node<T> *next;
+  List_Node<T> *prev;
+  int cap;
+  int len;
+  T data[];
+};
+
+template<class T>
+struct List{
+  int block_size            = 0;
+  int allocation_multiplier = 0;
+  List_Node<T> *first       = 0;
+  List_Node<T> *last        = 0;
+  List_Node<T> *first_free  = 0;
+};
+
 #endif
 
 enum Token_Kind{