diff --git a/src/lexer.c b/src/lexer.c
index f43df3d..9fd644e 100644
--- a/src/lexer.c
+++ b/src/lexer.c
@@ -6,6 +6,7 @@
 
 #include <assert.h>
 #include <stdlib.h>
+#include <string.h>
 
 static char buffer[1024];
 static size_t buffer_index = 0;
@@ -15,6 +16,22 @@ static void buffer_add(char chr);
 static void buffer_clean();
 static void token_add(Tokens tokens, enum State state, char *val);
 
+Lexer Lexer_new(const Tokens tokens)
+{
+    assert(tokens);
+    const Lexer self = malloc(sizeof(struct Lexer));
+    assert(self);
+    memset(self, 0, sizeof(struct Lexer));
+    self->tokens = tokens;
+    return self;
+}
+
+void Lexer_delete(const Lexer self)
+{
+    assert(self);
+    free(self);
+}
+
 void buffer_add(char chr)
 {
     assert(buffer_index < 1000);
@@ -37,7 +54,7 @@ void token_add(Tokens tokens, enum State state, char *val)
     Tokens_append(tokens, token_type, val);
 }
 
-void lex(Tokens tokens, const char chr)
+void Lexer_lex(const Lexer self, const char chr)
 {
     switch (state) {
     case STATE_INIT:
@@ -77,49 +94,49 @@ void lex(Tokens tokens, const char chr)
         break;
     case STATE_WHITESPACE:
         if (chr == '(') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_ROUND_OPEN;
             buffer_add(chr);
         } else if (chr == ')') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_ROUND_CLOSE;
             buffer_add(chr);
         } else if (chr == '[') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_SQUARE_OPEN;
             buffer_add(chr);
         } else if (chr == ']') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_SQUARE_CLOSE;
             buffer_add(chr);
         } else if (chr == '{') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_CURLY_OPEN;
             buffer_add(chr);
         } else if (chr == '}') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_CURLY_CLOSE;
             buffer_add(chr);
         } else if (chr == '\'') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_QUOTE;
             buffer_add(chr);
         } else if (is_space(chr)) {
             buffer_add(chr);
         } else if (is_ident_head(chr)) {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_IDENT;
             buffer[buffer_index++] = chr;
         } else if (is_number(chr)) {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_NUM;
             buffer[buffer_index++] = chr;
@@ -135,52 +152,52 @@ void lex(Tokens tokens, const char chr)
     case STATE_CURLY_CLOSE:
     case STATE_QUOTE:
         if (chr == '(') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_ROUND_OPEN;
             buffer_add(chr);
         } else if (chr == ')') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_ROUND_CLOSE;
             buffer_add(chr);
         } else if (chr == '[') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_SQUARE_OPEN;
             buffer_add(chr);
         } else if (chr == ']') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_SQUARE_CLOSE;
             buffer_add(chr);
         } else if (chr == '{') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_CURLY_OPEN;
             buffer_add(chr);
         } else if (chr == '}') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_CURLY_CLOSE;
             buffer_add(chr);
         } else if (chr == '\'') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_QUOTE;
             buffer_add(chr);
         } else if (is_space(chr)) {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_WHITESPACE;
             buffer_add(chr);
         } else if (is_ident_head(chr)) {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_IDENT;
             buffer_add(chr);
         } else if (is_number(chr)) {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_NUM;
             buffer_add(chr);
@@ -190,37 +207,37 @@ void lex(Tokens tokens, const char chr)
         break;
     case STATE_IDENT:
         if (chr == '(') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_ROUND_OPEN;
             buffer_add(chr);
         } else if (chr == ')') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_ROUND_CLOSE;
             buffer_add(chr);
         } else if (chr == '[') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_SQUARE_OPEN;
             buffer_add(chr);
         } else if (chr == ']') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_SQUARE_CLOSE;
             buffer_add(chr);
         } else if (chr == '{') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_CURLY_OPEN;
             buffer_add(chr);
         } else if (chr == '}') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_CURLY_CLOSE;
             buffer_add(chr);
         } else if (is_space(chr)) {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_WHITESPACE;
             buffer_add(chr);
@@ -232,37 +249,37 @@ void lex(Tokens tokens, const char chr)
         break;
     case STATE_NUM:
         if (chr == '(') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_ROUND_OPEN;
             buffer_add(chr);
         } else if (chr == ')') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_ROUND_CLOSE;
             buffer_add(chr);
         } else if (chr == '[') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_SQUARE_OPEN;
             buffer_add(chr);
         } else if (chr == ']') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_SQUARE_CLOSE;
             buffer_add(chr);
         } else if (chr == '{') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_CURLY_OPEN;
             buffer_add(chr);
         } else if (chr == '}') {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_CURLY_CLOSE;
             buffer_add(chr);
         } else if (is_space(chr)) {
-            token_add(tokens, state, buffer);
+            token_add(self->tokens, state, buffer);
             buffer_clean();
             state = STATE_WHITESPACE;
             buffer_add(chr);
diff --git a/src/lexer.h b/src/lexer.h
index 92848b7..b5cb879 100644
--- a/src/lexer.h
+++ b/src/lexer.h
@@ -3,6 +3,20 @@
 
 #include "tokens.h"
 
-void lex(Tokens tokens, char chr);
+#include <stddef.h>
+
+#define LEXER_DELETE(lexer) do { \
+    Lexer_delete(lexer);         \
+    lexer = NULL;                \
+} while (0)
+
+typedef struct Lexer {
+    Tokens tokens;
+} *Lexer;
+
+Lexer Lexer_new(Tokens tokens);
+void Lexer_delete(Lexer lexer);
+
+void Lexer_lex(Lexer self, char chr);
 
 #endif
diff --git a/src/main.c b/src/main.c
index b255db4..8d187f9 100644
--- a/src/main.c
+++ b/src/main.c
@@ -116,11 +116,13 @@ struct Object *eval_list(struct Object *const object)
 void run()
 {
     Tokens tokens = Tokens_new();
+    Lexer lexer = Lexer_new(tokens);
     assert(tokens);
     char chr;
     while ((chr = getchar()) != EOF) {
-        lex(tokens, chr);
+        Lexer_lex(lexer, chr);
     }
+    LEXER_DELETE(lexer);
 
     printf("\n=== TOKENS =======\n");
     for (