diff --git a/include/evaluator.h b/include/evaluator.h
index 0e63307..7ee78ce 100644
--- a/include/evaluator.h
+++ b/include/evaluator.h
@@ -7,6 +7,7 @@
 typedef enum {
     EVALUATOR_OK,
     EVALUATOR_MATH_ERR,
+    EVALUATOR_DIVISION_BY_ZERO,
     EVALUATOR_INVALID_PARSING,
     EVALUATOR_INVALID_TREE, // just to shut up the compiler with the swithces
 } EvaluatorErr;
diff --git a/include/parser.h b/include/parser.h
index 3a6b197..f4b4219 100644
--- a/include/parser.h
+++ b/include/parser.h
@@ -45,7 +45,7 @@ typedef struct {
     union {
         ParserErr err;
         struct {
-            Arena arena;
+            Arena *arena;
             Node *tree;
         };
     };
diff --git a/src/lexer.c b/src/lexer.c
index 23803c3..367c4c2 100644
--- a/src/lexer.c
+++ b/src/lexer.c
@@ -15,7 +15,8 @@ typedef enum {
 
 
 TokenizeResult tokenize(const char *input) {
-    ArrayList *arr = arraylist_init(64, sizeof(Token));
+    ArrayList *arr;
+    arraylist_init(&arr, 64, sizeof(Token));
     size_t offset = 0;
 
     while (input[offset] != '\0') {
diff --git a/src/parser.c b/src/parser.c
index 82d04a9..5722a10 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -296,10 +296,12 @@ ParserResult parse(TokenizeResult tokens) {
         };
     }
 
-    ArraySlice *context = arraylist_slice(tokens.arr, 0, arraylist_size(tokens.arr));
-    Arena arena = arena_init(sizeof(Node) * arraylist_size(tokens.arr)).arena;
+    ArraySlice *context;
+    arraylist_slice(&context, tokens.arr, 0, arraylist_size(tokens.arr));
+    Arena *arena;
+    arena_init(&arena, sizeof(Node) * arraylist_size(tokens.arr));
 
-    TreeResult result = parse_expr(context, &arena, 0);
+    TreeResult result = parse_expr(context, arena, 0);
     if (!result.is_valid) {
         arena_destroy(&arena);
         arraylist_destroy(&tokens.arr);