diff --git a/src/parser.h b/src/parser.h
index 8088efa..5c3a461 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -1,2 +1,5 @@
+#ifndef __PARSERCONSTS__
+#define __PARSERCONSTS__
 #define OPERAND_DELIMITER ", "
-#define HALT_ASM_CMD "and x0, x0, x0"
\ No newline at end of file
+#define HALT_ASM_CMD "and x0, x0, x0"
+#endif
\ No newline at end of file