diff --git a/syntax/sust.vim b/syntax/sust.vim
index acf1493..1cbad81 100644
--- a/syntax/sust.vim
+++ b/syntax/sust.vim
@@ -5,7 +5,7 @@ endif
 " syntax keyword Label args
 syn match Number /[ \r\n\t\v\-]*\d*[ \r\n\t\v$]*/
 syn keyword Special FUNC RETURN FUNC_END
-syn keyword Statement INIT_VAR SET_VAR TEMP_VAR MOVE_VAR COPY_VAR DROP_VAR HAS_VAR LIST_SIZE TO_STRING ADD_INT ADD_FLOAT ADD_STR SUB_STR SUB_LIST FOR FOR_MAP FOR_LIST WHILE WRITE READ READ_ALL READ_STR READ_STR_ALL OPEN_FILE_IN OPEN_FILE_OUT OPEN_TCP_CONNECTION OPEN_TCP_LISTENER EQUALS MORE LESS AND OR IF HAS_STR HAS_ITEM HAS_ENTRY HAS_KEY HAS_VALUE HAS_OPTIONAL USE_FUNC SLEEP NEW_THREAD
+syn keyword Statement INIT_VAR SET_VAR TEMP_VAR MOVE_VAR COPY_VAR DROP_VAR HAS_VAR LIST_SIZE TO_STRING ADD_INT ADD_FLOAT ADD_STR SUB_STR SUB_LIST FOR FOR_MAP FOR_LIST WHILE WRITE READ READ_ALL READ_STR READ_STR_ALL OPEN_FILE_IN OPEN_FILE_OUT OPEN_TCP_CONNECTION OPEN_TCP_LISTENER EQUALS MORE LESS AND OR IF HAS_STR HAS_ITEM HAS_ENTRY HAS_KEY HAS_VALUE HAS_OPTIONAL USE_FUNC SLEEP NEW_THREAD TO_BYTES TO_INTEGER TO_CHAR TO_BOOL TO_FLOAT GET_SYMBOL NOT
 syn keyword Type bool string integer float char list map optinal in_stream out_stream
 
 syntax match Comment /#.*$/