diff --git a/src/built_ins.cpp b/src/built_ins.cpp
index f90534f..28b39f6 100644
--- a/src/built_ins.cpp
+++ b/src/built_ins.cpp
@@ -537,7 +537,7 @@ proc load_built_ins_into_environment() -> void {
         Environment* target_env;
         in_caller_env {
             val = eval_expr(val);
-            target_env = find_binding_environment(sym->value.symbol.identifier, get_current_environment());
+            target_env = find_binding_environment(sym, get_current_environment());
             try assert(target_env);
         }
 
diff --git a/src/env.cpp b/src/env.cpp
index 622a861..180a03a 100644
--- a/src/env.cpp
+++ b/src/env.cpp
@@ -1,21 +1,21 @@
 proc define_symbol(Lisp_Object* symbol, Lisp_Object* value) -> void {
     Environment* env = get_current_environment();
-    hm_set(env->hm, Memory::get_c_str(symbol->value.symbol.identifier), value);
+    hm_set(env->hm, symbol, value);
 }
 
-inline proc lookup_symbol_in_this_envt(String* identifier, Environment* env) -> Lisp_Object* {
-    return (Lisp_Object*)hm_get_object(env->hm, Memory::get_c_str(identifier));
+inline proc lookup_symbol_in_this_envt(Lisp_Object* sym, Environment* env) -> Lisp_Object* {
+    return (Lisp_Object*)hm_get_object(env->hm, sym);
 }
 
-proc environment_binds_symbol(String* identifier, Environment* env) -> bool {
-    return lookup_symbol_in_this_envt(identifier, env) != nullptr;
+proc environment_binds_symbol(Lisp_Object* sym, Environment* env) -> bool {
+    return lookup_symbol_in_this_envt(sym, env) != nullptr;
 }
 
-proc find_binding_environment(String* identifier, Environment* env) -> Environment* {
-    if (environment_binds_symbol(identifier, env))
+proc find_binding_environment(Lisp_Object* sym, Environment* env) -> Environment* {
+    if (environment_binds_symbol(sym, env))
         return env;
     for (int i = 0; i < env->parents.next_index; ++i) {
-        if (environment_binds_symbol(identifier, env->parents.data[i]))
+        if (environment_binds_symbol(sym, env->parents.data[i]))
             return env->parents.data[i];
     }
     return get_root_environment();
@@ -25,9 +25,8 @@ proc try_lookup_symbol(Lisp_Object* node, Environment* env) -> Lisp_Object* {
     static auto nil_sym = Memory::get_or_create_lisp_object_symbol("nil");
     static auto t_sym   = Memory::get_or_create_lisp_object_symbol("t");
     // first check current environment
-    String* identifier = node->value.symbol.identifier;
     Lisp_Object* result;
-    result = lookup_symbol_in_this_envt(identifier, env);
+    result = lookup_symbol_in_this_envt(node, env);
     if (result)
         return result;
 
@@ -98,9 +97,9 @@ proc print_environment_indent(Environment* env, int indent) -> void {
         // return;
     // }
 
-    for_str_hash_map (env->hm) {
+    for_ptr_hash_map (env->hm) {
         print_indent(indent);
-        printf("-> %s :: ", key);
+        printf("-> %s :: ", &(((Lisp_Object*)key)->value.symbol.identifier->data));
         print((Lisp_Object*)value);
         printf(" (%lld)", (unsigned long long)value);
         puts("");
diff --git a/src/memory.cpp b/src/memory.cpp
index afa88f2..56fdcbe 100644
--- a/src/memory.cpp
+++ b/src/memory.cpp
@@ -412,7 +412,7 @@ namespace Memory {
         if (parent)
             append_to_array_list(&env->parents, parent);
 
-        env->hm = create_String_hashmap();
+        env->hm = create_Void_Ptr_hashmap();
 
         return env;
     }
diff --git a/src/structs.cpp b/src/structs.cpp
index 797831e..6f367e3 100644
--- a/src/structs.cpp
+++ b/src/structs.cpp
@@ -140,13 +140,7 @@ struct Arguments {
 
 struct Environment {
     Environment_Array_List parents;
-    String_Hash_Map* hm;
-    // int       capacity;
-    // int       next_index;
-
-    // // TODO(Felix): Use a hashmap here.
-    // char**        keys;
-    // Lisp_Object** values;
+    Void_Ptr_Hash_Map* hm;
 };
 
 struct Function {