diff --git a/cclox_src/error_handler.hh b/cclox_src/error_handler.hh
index 503ac03..5d22a85 100644
--- a/cclox_src/error_handler.hh
+++ b/cclox_src/error_handler.hh
@@ -1,4 +1,5 @@
-#pragma once
+#ifndef ERROR_HANDLER_HH
+#define ERROR_HANDLER_HH
 
 #include <string>
 
@@ -9,3 +10,5 @@ struct ErrorHandler {
 
   bool had_error;
 };
+
+#endif
diff --git a/cclox_src/interpreter.cc b/cclox_src/interpreter.cc
index bb6b9f0..a495c02 100644
--- a/cclox_src/interpreter.cc
+++ b/cclox_src/interpreter.cc
@@ -1,6 +1,6 @@
 #include "interpreter.hh"
 #include "error_handler.hh"
-#include "scanner.hh"
+#include "tokenizer.hh"
 #include <cstdint>
 #include <fstream>
 #include <iostream>
diff --git a/cclox_src/interpreter.hh b/cclox_src/interpreter.hh
index 8917050..43bf306 100644
--- a/cclox_src/interpreter.hh
+++ b/cclox_src/interpreter.hh
@@ -1,3 +1,6 @@
-#pragma once
+#ifndef INTERPRETER_HH
+#define INTERPRETER_HH
 
 void run_interpreter(int argc, char *argv[]);
+
+#endif
diff --git a/cclox_src/object.cc b/cclox_src/scanner/object.cc
similarity index 100%
rename from cclox_src/object.cc
rename to cclox_src/scanner/object.cc
diff --git a/cclox_src/object.hh b/cclox_src/scanner/object.hh
similarity index 94%
rename from cclox_src/object.hh
rename to cclox_src/scanner/object.hh
index 00dfa55..605cc6a 100644
--- a/cclox_src/object.hh
+++ b/cclox_src/scanner/object.hh
@@ -1,4 +1,5 @@
-#pragma once
+#ifndef OBJECT_HH
+#define OBJECT_HH
 
 #include <cstdint>
 #include <iostream>
@@ -33,3 +34,5 @@ struct Object {
 
 std::ostream &operator<<(std::ostream &os, const ObjectType &type);
 std::ostream &operator<<(std::ostream &os, const Object &obj);
+
+#endif
diff --git a/cclox_src/scanner.cc b/cclox_src/scanner/scanner.cc
similarity index 99%
rename from cclox_src/scanner.cc
rename to cclox_src/scanner/scanner.cc
index 2bd0668..57f0bf4 100644
--- a/cclox_src/scanner.cc
+++ b/cclox_src/scanner/scanner.cc
@@ -1,7 +1,7 @@
 #include "scanner.hh"
 #include "token.hh"
-#include "error_handler.hh"
 #include "object.hh"
+#include "../error_handler.hh"
 #include <string>
 #include <vector>
 
diff --git a/cclox_src/scanner.hh b/cclox_src/scanner/scanner.hh
similarity index 93%
rename from cclox_src/scanner.hh
rename to cclox_src/scanner/scanner.hh
index e819094..00febb6 100644
--- a/cclox_src/scanner.hh
+++ b/cclox_src/scanner/scanner.hh
@@ -1,4 +1,5 @@
-#pragma once
+#ifndef SCANNER_HH
+#define SCANNER_HH
 
 #include "token.hh"
 #include <cstddef>
@@ -29,3 +30,5 @@ struct Scanner {
   std::size_t start, current, line;
   std::unordered_map<std::string, TokenType> keywords;
 };
+
+#endif
diff --git a/cclox_src/token.cc b/cclox_src/scanner/token.cc
similarity index 100%
rename from cclox_src/token.cc
rename to cclox_src/scanner/token.cc
diff --git a/cclox_src/token.hh b/cclox_src/scanner/token.hh
similarity index 95%
rename from cclox_src/token.hh
rename to cclox_src/scanner/token.hh
index ed88260..032e13e 100644
--- a/cclox_src/token.hh
+++ b/cclox_src/scanner/token.hh
@@ -1,4 +1,5 @@
-#pragma once
+#ifndef TOKEN_HH
+#define TOKEN_HH
 
 #include "object.hh"
 #include <cstdint>
@@ -39,3 +40,5 @@ struct Token {
 
 std::ostream &operator<<(std::ostream &os, const TokenType &type);
 std::ostream &operator<<(std::ostream &os, const Token &token);
+
+#endif
diff --git a/cclox_src/tokenizer.cc b/cclox_src/tokenizer.cc
new file mode 100644
index 0000000..5d142a9
--- /dev/null
+++ b/cclox_src/tokenizer.cc
@@ -0,0 +1,8 @@
+#ifndef TOKENIZER_CC
+#define TOKENIZER_CC
+
+#include "scanner/object.cc"
+#include "scanner/token.cc"
+#include "scanner/scanner.cc"
+
+#endif
diff --git a/cclox_src/tokenizer.hh b/cclox_src/tokenizer.hh
new file mode 100644
index 0000000..546936e
--- /dev/null
+++ b/cclox_src/tokenizer.hh
@@ -0,0 +1,8 @@
+#ifndef TOKENIZER_HH
+#define TOKENIZER_HH
+
+#include "scanner/object.hh"
+#include "scanner/token.hh"
+#include "scanner/scanner.hh"
+
+#endif