Switch to using header guards instead of pragma once

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

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>

cclox_src/interpreter.hh

@@ -1,3 +1,6 @@
-#pragma once
+#ifndef INTERPRETER_HH
+#define INTERPRETER_HH
 
 void run_interpreter(int argc, char *argv[]);
+
+#endif

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

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>
 

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

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

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

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