diff --git a/include/lexer.h b/include/lexer.h
index fcb6529..ed8c1e2 100644
--- a/include/lexer.h
+++ b/include/lexer.h
@@ -20,15 +20,6 @@ typedef enum {
     OP_DIV
 } Operator;
 
-typedef enum {
-    ARRAY_OK = 0,
-    ARRAY_NULL,
-    ARRAY_EMPTY,
-    ARRAY_OUT_OF_BOUNDS,
-    ARRAY_NULL_ARG,
-    ARRAY_ALLOC,
-} ASTNodeArrayErr;
-
 typedef enum {
     LEXER_OK = 0,
     LEXER_INT_OVERFLOW,
@@ -76,20 +67,6 @@ typedef struct {
         int64_t number;
     };
 } I64Result;
-// I prefer ot have a dynamic array for storing the "tokens"
-typedef struct {
-    size_t len;
-    size_t cap;
-    ASTNode *data;
-} ASTNodeArray;
-
-ASTNodeArray ASTNodeArray_init(size_t size);
-void ASTNodeArray_free(ASTNodeArray *arr);
-ASTNodeArrayErr ASTNodeArray_push(ASTNodeArray *arr, ASTNode node);
-ASTNodeArrayErr ASTNodeArray_get(const ASTNodeArray *arr, size_t index, ASTNode *out);
-// Out in pop can be NULL so it doesn't return anything
-ASTNodeArrayErr ASTNodeArray_pop(ASTNodeArray *arr, size_t index, ASTNode *out);
-size_t ASTNodeArray_len(ASTNodeArray *arr);
 
 // Lexer funtions as well as few functionality
 TokenizeResult tokenize(const char* input);
diff --git a/include/parser.h b/include/parser.h
index 7c2fa4f..158b348 100644
--- a/include/parser.h
+++ b/include/parser.h
@@ -3,33 +3,39 @@
 
 #include "lexer.h"
 #include "arena.h"
+#include "arraylist.h"
 #include <stdint.h>
 
 typedef struct {
     ASTNode *head;
 } AST;
 
-typedef struct {
-    ASTNodeArray *arr;
-    size_t pos;
-} ASTNodeSlice;
+typedef enum {
+    PARSER_OK = 0,
+    PARSER_UNEXPECTED_TOKEN,
+    PARSER_MISSING_OPERAND,
+    PARSER_UNMATCHED_PAREN,
+    PARSER_OUT_OF_MEMORY,
+} ParserErr;
 
 typedef struct {
-    Arena arena;
-    ASTNode *tree;
+    bool is_valid;
+    union {
+        ParserErr err;
+        struct {
+            Arena arena;
+            ASTNode *tree;
+        };
+    };
 } ParseResult;
 
-ASTNode ASTNodeSlice_peek(ASTNodeSlice *slice);
-ASTNode ASTNodeSlice_next(ASTNodeSlice *slice);
-bool ASTNodeSlice_is_valid(ASTNodeSlice *slice);
-
-ASTNode *nud(ASTNodeSlice *slice);
-ASTNode *led(ASTNodeSlice *slice, size_t right_precedence);
+ASTNode *nud(ArraySlice *slice);
+ASTNode *led(ArraySlice *slice, size_t right_precedence);
 
 uint8_t node_lbp(ASTNode node);
 uint8_t node_rbp(ASTNode node);
 
-ParseResult parse(ASTNodeArray *arr);
-ASTNode *parse_expr(ASTNodeSlice *slice, Arena *arena, uint8_t min_bp);
+ParseResult parse(TokenizeResult tokens);
+ASTNode *parse_expr(ArraySlice *slice, Arena *arena, uint8_t min_bp);
 
 #endif // !PARSER_H
diff --git a/src/ASTNodeArray.c b/src/ASTNodeArray.c
deleted file mode 100644
index a9f2053..0000000
--- a/src/ASTNodeArray.c
+++ /dev/null
@@ -1,108 +0,0 @@
-#include "lexer.h"
-#include <stdlib.h>
-
-#define NODE_ARRAY_DEFAULT_SIZE 64
-// Helps  state machine for the lexer :)
-typedef enum {
-    WAIT_FOR_NUMBER,
-    WAIT_FOR_OPERATOR,
-} LexerState;
-
-ASTNodeArray ASTNodeArray_init(size_t size) {
-    ASTNodeArray new;
-    new.len = 0;      // if 0 then use default
-    new.cap = size == 0 ? NODE_ARRAY_DEFAULT_SIZE : size;
-    new.data = malloc(new.cap * sizeof(ASTNode));
-    return new;
-}
-
-void ASTNodeArray_free(ASTNodeArray *arr) {
-    free(arr->data);
-    arr->cap = 0;
-    arr->len = 0;
-}
-
-ASTNodeArrayErr ASTNodeArray_get(const ASTNodeArray *arr, size_t index, ASTNode *out) {
-    if (arr == NULL) {
-        return ARRAY_NULL;
-    }
-
-    if (out == NULL) {
-        return ARRAY_NULL_ARG;
-    }
-
-    if (arr->len == 0) {
-        return ARRAY_EMPTY;
-    }
-
-    if (index >= arr->len) {
-        return ARRAY_OUT_OF_BOUNDS;
-    }
-
-    *out = arr->data[index];
-
-    return ARRAY_OK;
-}
-
-ASTNodeArrayErr ASTNodeArray_push(ASTNodeArray *arr, ASTNode node) {
-    if (arr == NULL) {
-        return ARRAY_NULL;
-    }
-
-    if (arr->len >= arr->cap) {
-        size_t new_cap = arr->cap * 2;
-        ASTNode *tmp = realloc(arr->data, new_cap * sizeof(ASTNode));
-        if (tmp == NULL) {
-            return ARRAY_ALLOC;
-        }
-        arr->data = tmp;
-        arr->cap = new_cap;
-    }
-
-    arr->data[arr->len] = node;
-    arr->len = arr->len + 1;
-
-    return ARRAY_OK;
-}
-
-ASTNodeArrayErr ASTNodeArray_pop(ASTNodeArray *arr, size_t index, ASTNode *out) {
-    if (arr == NULL) {
-        return ARRAY_NULL;
-    }
-
-    if (arr->len == 0) {
-        return ARRAY_EMPTY;
-    }
-
-    if (index >= arr->len) {
-        return ARRAY_OUT_OF_BOUNDS;
-    }
-
-    if (arr->cap / 4 > arr->len) {
-        size_t new_cap = arr->cap / 2;
-        ASTNode *tmp = realloc(arr->data, new_cap * sizeof(ASTNode));
-        if (tmp == NULL) {
-            return ARRAY_ALLOC;
-        }
-        arr->data = tmp;
-        arr->cap = new_cap;
-    }
-    
-    if (out != NULL) {
-        ASTNode node_to_delete = arr->data[index];
-        *out = node_to_delete;
-    }
-
-    for (size_t i = index; i < arr->len - 1; i++) {
-        arr->data[index] = arr->data[index + 1];
-    }
-
-    return ARRAY_OK;
-}
-
-size_t ASTNodeArray_len(ASTNodeArray *arr) {
-    if (arr == NULL) {
-        return 0;
-    }
-    return arr->len;
-}
diff --git a/src/main.c b/src/main.c
index 9cc1240..89cfc64 100644
--- a/src/main.c
+++ b/src/main.c
@@ -19,10 +19,9 @@ int main(void) {
     }
     buf[pos] = '\0';
 
-    ASTNodeArray context;
-    tokenize(buf, &context);
+    TokenizeResult tokens = tokenize(buf);
 
-    ParseResult par = parse(&context);
+    ParseResult par = parse(tokens);
     int64_t result = evaluate(par);
 
 
diff --git a/src/parser.c b/src/parser.c
index 9f454ef..a3efae0 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -1,4 +1,5 @@
 #include "parser.h"
+#include "arraylist.h"
 #include "lexer.h"
 #include "arena.h"
 #include <stdalign.h>
@@ -41,38 +42,17 @@ uint8_t node_rbp(ASTNode node) {
     }
 }
 
-ASTNode ASTNodeSlice_next(ASTNodeSlice *slice) {
-    return slice->arr->data[slice->pos++];
-}
-
-ASTNode ASTNodeSlice_peek(ASTNodeSlice *slice) {
-    return slice->arr->data[slice->pos];
-}
-
-bool ASTNodeSlice_is_valid(ASTNodeSlice *slice) {
-    if (slice->arr->len < 1) {
-        return false;
-    }
-    if (slice->pos >= slice->arr->len) {
-        return false;
-    }
-
-    return true;
-}
-
-ParseResult parse(ASTNodeArray *arr) {
-    ASTNodeSlice context = {
-        .arr = arr,
-        .pos = 0,
-    };
-    Arena arena = arena_init(sizeof(ASTNode) * arr->len).arena;
+ParseResult parse(TokenizeResult tokens) {
+    ArraySlice *context = arraylist_slice(tokens.arr, 0, arraylist_size(tokens.arr));
+    Arena arena = arena_init(sizeof(ASTNode) * arraylist_size(tokens.arr)).arena;
 
     return (ParseResult) {
+        .is_valid = true,
         .arena = arena,
-        .tree = parse_expr(&context, &arena, 0)};
+        .tree = parse_expr(context, &arena, 0)};
 }
 
-ASTNode *parse_expr(ASTNodeSlice *slice, Arena *arena, uint8_t min_bp) {
+ASTNode *parse_expr(ArraySlice *slice, Arena *arena, uint8_t min_bp) {
     arena_ensure_capacity(
         arena,
         sizeof(ASTNode),
@@ -87,14 +67,15 @@ ASTNode *parse_expr(ASTNodeSlice *slice, Arena *arena, uint8_t min_bp) {
         )
     );
 
-    *left_side = ASTNodeSlice_next(slice);
+    arrayslice_next(slice, left_side);
 
     while (true) {
-        if (!ASTNodeSlice_is_valid(slice)) {
+        if (!arrayslice_is_valid(slice)) {
             break;
         }
 
-        ASTNode operator = ASTNodeSlice_peek(slice);
+        ASTNode operator;
+        arrayslice_peek(slice, &operator);
         uint8_t rbp = node_rbp(operator);
         uint8_t lbp = node_lbp(operator);
 
@@ -102,7 +83,7 @@ ASTNode *parse_expr(ASTNodeSlice *slice, Arena *arena, uint8_t min_bp) {
             break;
         }
 
-        ASTNodeSlice_next(slice);
+        arrayslice_next(slice, NULL);
         ASTNode *right_side = parse_expr(slice, arena, rbp);
 
         arena_ensure_capacity(