diff --git a/12/definition.hpp b/12/definition.hpp
index c14ec0f..d70d539 100644
--- a/12/definition.hpp
+++ b/12/definition.hpp
@@ -1,6 +1,7 @@
 #pragma once
 #include <memory>
 #include <vector>
+#include <map>
 #include <set>
 #include "instruction.hpp"
 #include "llvm_context.hpp"
@@ -70,3 +71,8 @@ struct definition_data {
 };
 
 using definition_data_ptr = std::unique_ptr<definition_data>;
+
+struct definition_group {
+    std::map<std::string, definition_data_ptr> defs_data;
+    std::map<std::string, definition_defn_ptr> defs_defn;
+};
diff --git a/12/main.cpp b/12/main.cpp
index 45a3e8b..6495d92 100644
--- a/12/main.cpp
+++ b/12/main.cpp
@@ -21,8 +21,7 @@ void yy::parser::error(const std::string& msg) {
     std::cout << "An error occured: " << msg << std::endl;
 }
 
-extern std::map<std::string, definition_data_ptr> defs_data;
-extern std::map<std::string, definition_defn_ptr> defs_defn;
+extern definition_group global_defs;
 
 void typecheck_program(
         const std::map<std::string, definition_data_ptr>& defs_data,
@@ -180,7 +179,7 @@ int main() {
     type_env_ptr env(new type_env);
 
     parser.parse();
-    for(auto& def_defn : defs_defn) {
+    for(auto& def_defn : global_defs.defs_defn) {
         std::cout << def_defn.second->name;
         for(auto& param : def_defn.second->params) std::cout << " " << param;
         std::cout << ":" << std::endl;
@@ -188,9 +187,9 @@ int main() {
         def_defn.second->body->print(1, std::cout);
     }
     try {
-        typecheck_program(defs_data, defs_defn, mgr, env);
-        compile_program(defs_defn);
-        gen_llvm(defs_data, defs_defn);
+        typecheck_program(global_defs.defs_data, global_defs.defs_defn, mgr, env);
+        compile_program(global_defs.defs_defn);
+        gen_llvm(global_defs.defs_data, global_defs.defs_defn);
     } catch(unification_error& err) {
         std::cout << "failed to unify types: " << std::endl;
         std::cout << "  (1) \033[34m";
diff --git a/12/parser.y b/12/parser.y
index 686e79e..5256fae 100644
--- a/12/parser.y
+++ b/12/parser.y
@@ -7,8 +7,7 @@
 #include "parser.hpp"
 #include "parsed_type.hpp"
 
-std::map<std::string, definition_data_ptr> defs_data;
-std::map<std::string, definition_defn_ptr> defs_defn;
+definition_group global_defs;
 
 extern yy::parser::symbol_type yylex();
 
@@ -63,8 +62,8 @@ definitions
     ;
 
 definition
-    : defn { auto name = $1->name; defs_defn[name] = std::move($1); }
-    | data { auto name = $1->name; defs_data[name] = std::move($1); }
+    : defn { auto name = $1->name; global_defs.defs_defn[name] = std::move($1); }
+    | data { auto name = $1->name; global_defs.defs_data[name] = std::move($1); }
     ;
 
 defn