1 files changed, 1 insertions, 0 deletions
diff --git a/dat.h b/dat.h
index e085acd..e01276d 100644
--- a/dat.h
+++ b/dat.h
@@ -59,6 +59,7 @@ struct Predicate
 	Rune *name;
 	int arity;
 	int public;
+	int builtin; /* All the predicates from the system module are builtin */
 	Clause *clauses;
 	Predicate *next;
 };